Connecting a New Foundation to an Old One

Posted on by Tim Carter
connect new foundation to existing

Connect new foundation to existing: Those two pieces of vertical rebar help lock two different pours of concrete together. You start the foundation with a footer or footing. This footing will soon have a foundation wall on it directly over the keyway groove in the concrete. The clay soil beneath it is extremely stable. © 2017 Tim Carter

"You have numerous options with respect to making a physical connection between the two foundations. I've successfully installed steel pins that are epoxied into the old foundation."

Connect New Foundation to Existing Checklist

DEAR TIM: I'm building an addition on my home and realize I must connect the new foundation with the existing one. What's the best way to do this? Is there a way to waterproof the connection?

Will this connection become a hinge point in the future causing cracks in the walls? I am very concerned about how to make a connection between the structures that will stand the test of time. Paul M., Orono, MN

DEAR PAUL: I can remember many years ago having these same thoughts when I was building my first room addition. I couldn't figure out how the shallow crawlspace foundation would stay connected to the full basement foundation since they were at different elevations.

My geology professors would have frowned at me had they been at the job site. I was not thinking through how to connect the new foundation to the existing one.

Is a Foundation Wall a Beam?

Many people fail to realize that a typical foundation wall is, among other things, a beam. You begin to see this if you look at the vertical web in a steel I beam or even a simple wooden floor joist.

connect new foundation to existing

Note how the tall poured walls look just like the center web of an I-beam.  Copyright 2018 Tim Carter

Understanding this is essential. Steel I beams derive much of their strength by the thickness and height of the vertical web section of the I beam. It's important to realize steel I-beams gain a great amount of strength from the top and bottom flanges. The top flange is the flat part that ironworkers walk on as they erect the steel.

Can Taller Beams Span Farther?

Generally speaking the taller the vertical web, the farther the beam can span between supports. You can see this clearly if you pay attention to bridges that cross many of the interstate highways you might travel here in the USA.

Some of the bridges span 100, or more, feet between the poured concrete supports at each end of the bridge. The steel I-beams are often 3, 4 or 5 feet tall whereas the typical I-beam in a house basement might only be 8 inches tall.

A foundation wall is no different other than the fact its vertical height is ten or fifteen times greater than a typical residential I beam.

How Important is Soil Strength?

The soil strength is the most important thing of all. Strong soil will not allow the new foundation to drop below the existing one you're connecting to.

If you accept this principal, then it stands to reason the foundation will not flex up or down if the soil beneath this beam is solid.

This is perhaps the most important aspect of connecting the two foundations. The soil under a foundation of the existing house and the foundation must be strong.

If it is, then there's no reason the room addition foundation will sink or pivot next to the existing house.

CLICK HERE to get FREE & FAST BIDS from local SOIL engineers to ensure your foundation is fine.

What are Foundation Steps?

Foundation steps are parts of a continuous wall that are different heights. When you face the wall the top of the foundation appears to be a giant staircase. The photo above shows a side wall with two steps to the right of the highest part of the foundation.

Foundation steps are used when a house is built on a steep or shallow hillside.

When new homes are built, it's often a common practice to pour different parts of the foundation at different times and at different heights within the soil profile. The fact that you are installing the foundations years apart instead of days will make no difference.

I was able to tape three videos of a new foundation going in for a detached garage being constructed here in central New Hampshire just two houses away from my own home. This was NOT my job. I was just a spectator.

Can Footings Be Stepped?

Yes, a footing can be stepped. These are necessary to keep the footing below the frost level when a house is built on a hillside.

But the garage had a stepped footer. Meaning the footer was at different levels just like your addition will be with respect to your home.

WATCH THESE THREE VIDEOS TO SEE FOUNDATION / FOOTING STEPS:


Should the Foundation Contain Reinforcing Steel?

The masonry foundation or the slab should also contain structural steel. Dual horizontal steel bars 12 to 16 inches from the top and bottom of poured concrete foundations help to create a stiff concrete beam.

Concrete block foundations can incorporate steel truss fabric that is installed in every other row of the concrete block units. Filling the hollow cores of concrete block foundations with a pea-gravel concrete slurry also adds strength.

Concrete slabs can contain 1/2-inch diameter steel bars on two-foot centers in both directions to stiffen the slab substantially. A residential structural engineer can easily specify the best solution for your particular situation.

foundation footer

This is the footer under the laundry room portion of my home. Note the distinct soil profiles. My house is built on glacial till. In fact, both visible soil profiles may represent two separate glacial episodes! © 2017 Tim Carter

How Do You Connect a New Footing to an Existing One?

Use steel rods to connect a new footing to an existing one. Drill a hole into the existing footing the same diameter as the steel bar. The depth should be at least 4 inches. Hammer a 10-inch length of steel bar into the hole leaving at least 6 inches to extend into the new footing.

You have numerous options with respect to making a physical connection between the two foundations. I've successfully installed steel pins that are epoxied into the old foundation.

On other jobs, I've bolted a steel angle iron to the existing foundation. The concrete of the footing is poured on the flat part of the angle iron. You can see how it would help hold the footing to the existing foundation just as a shelf cleat hold a shelf in a closet or pantry

Is it Okay to Encapsulate the Steel in the Concrete?

These building components then become encapsulated by the masonry materials that are used to create the new room addition foundation. It's always best to hire a structural engineer to create a design for this connection.

This is especially true if you live in an area with expansive clay soils or an area that is subject to seismic movement.

CLICK HERE to get FREE & FAST BIDS from local STRUCTURAL engineers who'll help you.

Can the New Connection be Waterproof?

There are special waterproof connection materials that work well when connecting a poured concrete foundation to an existing one. These flexible waterproofing materials look like weatherstripping on steroids as they have small fins that project from the center of the main strip.

The base is epoxied and sealed to the existing foundation and the strip projects into the center of the foundation form. When the wet concrete surrounds the strip, you have a waterproof joint so long as the foundations do not pull apart from one another.

How do You Waterproof the New Foundation Connection?

I feel the best way to waterproof new foundations is to apply special waterproofing compounds to the exterior of the finished foundation. There are many different products and systems but all rely on excellent drainage around the foundation.

You need to make sure your drainage system can collect the subsurface water and transport it to a low spot on your property or into a sump pit where it can be pumped to a stormwater collection system.

Do Deep Piers Help in Weak Soil?

Yes, piers help hold up a foundation in weak soil.

Soil stability is everything when it comes to foundations. If the soil quality is suspect, you can ensure a stable foundation by installing piers under the foundation footer.

Piers can be made from concrete, steel or wood, but a common one is a simple vertical hole that extends into the soil until it finds bedrock or stable soil. This hole is then filled with concrete

Piers can be spaced at eight or ten-foot intervals and resemble table legs. The foundation, which is a beam, simply transfers its load down and through the individual piers instead of the unstable soil in between the piers.

CLICK HERE to get FREE & FAST BIDS from local STRUCTURAL engineers who'll help you.

Column 500

Washing Machine Venting Diagram

Posted on by Tim Carter

Washing Machine Drain Vent TIPS

Kevin's Shortcut Vent

Kevin Garretty emailed me about a vexing problem at his Beaufort, SC home. He included a proposed drawing of what he wanted to do.

Believe it or not, he was darn close to doing it the right way.

He's scratching his head about the correct way to vent a washing machine and needs a venting diagram.

Tim's a Master Plumber

For the record, I'm a master plumber among other things. I was a master plumber at age 28 in Hamilton County, Ohio. Ten years later I sat and passed the master test for the City of Cincinnati and got my masters license.

I loved doing the plumbing on all my jobs. I think it was the challenge of the 3-D aspect of creating the network of drain and vent pipes that attracted me to the trade.

Think about it. You have one pipe leave a house to the sewer or septic system and often only one vent pipe up on the roof.

But in between, those pipes bifurcate like crazy. A master plumber needs to know how to make it all work so no sewer gas ever enters the house.

Kevin's Drawing

Here's what Kevin cooked up in his head.

"Is it OK to vent washer drain line, before the hard trap in the wall?"

washing machine drain pipe

This is Kevin's drawing. NEVER install a washing machine drain pipe and vent like this. Look at MY drawing below.

Kevin, the answer is NO. 

Suction

In your scenario, if a fixture that's farther upstream discharges lots of water that rushes by the wye fitting where your washing machine drain pipe connects, the vacuum created by the water rushing past the washing machine branch Wye will siphon water from your trap.

Correct Venting Prevents Suction

If you put the vent line at the connection point of the washing machine branch arm like you see in my drawing, the vacuum pulls the needed air from the vent pipe before it tries to get it on the other side of the trap. It's looking for the path of LEAST RESISTANCE to get the needed air.

Toilets - BIG Problems!

In my diagram, I've shown a half-bathroom upstream from the washing machine. Imagine what happens when that toilet is flushed! 

The rushing water fills the pipe completely and pushes the air in the pipe ahead of it towards the sewer. That air MUST BE REPLACED and as the water goes past wye fittings, it creates a vacuum at that point.

Tim's Drawing

I've included the proper pipe sizes for the system. The dashed lines are vent lines and note the one vent line for the half bath is a full-sized 3-inch vent that goes up and through the roof.

The pipe that drains the lavatory sink is 3-inch in diameter because that drain line also acts as a vent for the toilet. The 3-inch pipe would never completely fill with water even if you filled the lavatory sink and pulled the stopper. This wet venting is permitted by most codes.

I've done it for years on many systems, even at my own home, and never had a suction issue if you flush the toilet and let a full sink of lavatory water drain at the same time.

Remember that vent lines MUST be sloped so they drain water towards the sewer. You never want standing water in a vent line.

Washing Machine Venting Diagram

Note the pipe sizes. It's very important that a washing machine has a 2-inch drain line up to where it connects to the main stack. Look at the interesting wet venting of the toilet! READ the column above to understand how it works. (C) Copyright 2017 Tim Carter - Master Plumber

 

 

 

Excess Grout Removal

Posted on by Tim Carter

Grout Removal TIPS

DEAR TIM: I was grouting ceramic tile when I had to leave the house for an emergency. When I could finally get back to work the next day, the grout was hard as a rock. I have extra tile, should I just remove the mess I have now and start over? Is there a way to remove the hardened grout without harming the tile? Dan A., Orlando, FL

DEAR DAN: First, I hope all of those associated with the emergency situation are okay and doing well. As for your ceramic tile, I would not just yet pronounce it DOA (dead on arrival).

Depending upon certain factors, including but not limited to, amount of excess grout, the amount of time the grout has been left to harden, the surface texture of the tile, and the amount of patience you have, you may be able to salvage the tile job. It most definitely is worth a try.

CLICK HERE to get FREE & FAST BIDS from local tile repair contractors.

excess grout removal

These tools will get up most of the grout paste left behind. The wood stick with sharp edges will prevent scratches as you try to pop off large pieces of grout. Vacuum up the dust as you work, so the grout grit does not scratch the glazed tile.

Use Right Tools

The best tool to use is an oak wood stick with sharp edges will prevent scratches as you try to pop off large pieces of grout.

The easiest place to get oak is a pallet slat. Visit an business that uses pallets for incoming and outgoing freight and they'll have a crap pallet around.

You just have to peel off one of the top boards and then saw it so it's the shape of a paint stirring stick.

Paint Sticks Work Too

If getting oak is too much work, and it can be, then just use a paint stirring stick.

Slowly scrape the excess grout with the stick edge. Cut into the grout with the corner of the stick.

Do NOT attack the grout like a bulldozer cuts into a hill of dirt. The stick will ride up over the grout.

IMPORTANT TIP: Brush away or vacuum up the grout grit and dust as you work. If you don't, the grout grit will scratch the glazed tile.

Floor grout contains fine pieces of silica sand and it's extremely abrasive. The sand will scratch tile fast and it's just about impossible to repair the tiny scratches.

48 Hours

The primary ingredient in many ceramic tile grouts is Portland cement. It takes days and often weeks for ceramic tile grout to reach full strength.

At this point in time, you're working against the clock. Every hour after the grout was installed, it gets much harder to remove it.

I've found that if you start to remove excess grout within 48 hours after it was installed, it's not too hard.

The longer you hesitate to remove the grout, the harder it becomes to remove. If, by chance, the grout was an epoxy grout, you're toast. It's virtually impossible to remove excess epoxy grout from tile surfaces without damaging the tile.

Step-By-Step Tips

The grout removal process requires just a few simple tools. You need some small pieces of wood that have very square-cut edges and several brand new nylon scouring pads.

scotch brite dobie pad

This is the BEST grout removal tool I've ever used in conjunction with a wood stick. These nylon pads do a fantastic job. CLICK THE IMAGE ABOVE NOW TO ORDER THEM.

The first thing to do is to work in a small area to see how successful the grout removal techniques will be. If you have rapid success and can get a few tiles clean within a few minutes, that's a very good sign.

No Metal Tools

Use the wood sticks to remove large clumps and layers of grout. Do NOT use metal scraping tools, putty knives, etc. The metal will permanently damage the glazed surface of the tile.

Don't allow contractors to use metal tools.

CLICK HERE to get FREE & FAST BIDS from local tile repair contractors.

Oak is Best - Soft Woods Dull

I prefer to use pieces of oak that are 1/4 to 3/8 of an inch thick, one-inch wide and perhaps six inches long. The oak hardwood holds its square-cut edge longer than a softwood like most paint stirring sticks.

Use a power saw to make sure all of the edges are square cut instead of slightly rounded. The crisp square edge aggressively cuts through the grout down to the surface of the ceramic tile.

Add Water

Before you begin to attack the grout-covered tile with the stick, pour a little water on it. The water acts as a lubricant and helps to prevent micro-scratches on the glazed tile surface. It should not require excessive pressure to get immediate results.

The trick to removing large grout deposits is to just cut into the grout with a corner of the grout stick. Don't try to push the entire square face of the oak stick into a large clump of grout.

Once the heavy deposits of grout are removed using the oak stick, rinse off all of the grout particles and grit from the surface of the tile.

New MicroFiber Sponge

New tools and products hit the market all the time. Farther down below you'll see traditional grout sponges that work really well for this job.

But right here is a newer sponge that combines a microfiber surface on one side that really helps you get rid of the DRIED grout haze on ceramic tile. CLICK HERE NOW to order one of these sponges.

grout sponge

Here's a fantastic newer sponge that will do a great job of cleaning dried grout haze. CLICK THE IMAGE NOW TO BUY ONE.

Scrub Away

Add more fresh water to the surface of the tile. Get the nylon scouring pad wet as well. Begin to scour the tile surface with the pad adding plenty of fresh water as you scrub. You should see dramatic results within seconds.

Check for Scratches!

You can test to see if all of the grout paste has been removed by doing a final rinse on the tile(s) you just worked on. Use a soft cotton cloth to dry the tile. You can also dry it quickly with a regular fan or a hair dryer.

Remove Haze

Wet tile can trick you. It often looks perfect but frequently after it dries you will see a slight grout haze upon it. Hold a piece of spare tile next to the clean and dry tile to see if it has been restored to its original condition.

Add New Grout

The biggest challenge of the job will be restoring the grout lines between the tiles. When tile grout is wet, it is very easy to make the grout lines uniform using a special grout sponge that has rounded edges.

grout sponges with rounded edges

These are wonderful grout sponges with rounded edges. I've used these for decades with amazing results. CLICK THE PHOTO IMAGE NOW TO ORDER THESE SPONGES.

Carving Hard Grout

The sponge tools the grout line smooth. But now, the grout in between the tiles is anything but uniform. Use coarse sandpaper to slightly round off a corner of one of the oak sticks so that it resembles a woodworker's chisel.

As you push and pull the stick back and forth along the grout lines, the rounded corner will cut a profile similar to what the sponge would have created. Once again, introduce some water to the grout to act as a lubricant.

Do not give up if you do not see immediate results. Try to be patient with the wood stick as it may be far easier to dress the grout this way than to remove the grout and start over. If you do decide to re-grout, try to make sure you do when you will not be called away from the house!

Secret Sugar Trick

I know this is going to sound crazy, but try it. Take one gallon of warm water and dissolve a cup of sugar into it. Take this sweet solution and pour it onto excess grout on a floor. If you have wall tile with too much grout, then soak paper towels in the solution and place them on the tile.

Keep the tile wet with the sugar water for at least two hours. After this dwell time is complete, use a new Dobie nylon scrub pad and scrub a small area. You should see instant results. It may take more than one application of sugar water to completely remove the grout film.

CLICK HERE to get FREE & FAST BIDS from local tile repair contractors.

Column 433

Crawl Space Encapsulation or Not

Posted on by Tim Carter
crawl space vent

This is a typical crawl space vent that’s supposed to allow air into and out of a crawl space. They just don't work. It's like trying to breath through a small cocktail straw. © 2017 Tim Carter

Crawlspace Encapsulation TIPS

DEAR TIM: My head is spinning from all of the conflicting information I'm seeing online about crawl space encapsulation. Should it be done or should I just rely on the traditional vents I have in my foundation? I have a 1,100 square-foot crawl space and the slate floor above is ice cold because there's no insulation. What would you do if this were your home and why? - Richard J., Toledo, OH

DEAR RICHARD: I can understand your frustration. While the Internet is an amazing resource, the barrier to entry with respect to publishing is lower than the bottom of Death Valley. If you can fog a mirror and type on a keyboard, you're capable of posting your opinion about how you think things should be done on the Internet.

Bad JuJu Info

Back before the Internet, traditional book publishers would do a fairly good job of vetting an author before they agreed to publish his work. This filtering process kept much of the erroneous information out of the mainstream.

It was possible to self-publish, but those that chose to do this had a tough time distributing their work. The Internet has removed these barriers and filters.

To stop your head from spinning, let's dive into the science of crawl spaces. I prefer to base my opinions and beliefs on science, not speculation.

Bare Soil

A traditional crawl space under a home consists of soil or sand that was the ground before construction started. Sometimes the topsoil is removed, but what you see is bare soil. I've been in crawlspaces that have had concrete poured on top of the soil or some washed gravel.

Water Vapor Pump

Unless you live in the Atacama Desert, the ground under and around your home contains moisture. This liquid water wants to evaporate and get back up to the atmosphere. If you could see water vapor, you'd see a constant flow of this gas floating up into the air. When it's warm, the flow rate is faster.

Water = Mold

This water vapor, when mixed with wood, is not a good thing. If enough water vapor collects in a crawl space before getting back to the outside atmosphere, it can condense and turn to liquid water again. This water fuels mold growth and fungi growth you might call wood rot.

Old builders knew about this. The best they could do was to provide an escape path of the water vapor to the outside.

Crawl Space Vents

That's what the crawl space vents are for in your foundation. The trouble is, they don't work too well. I've been in crawl spaces when the wind is howling outdoors and barely have felt a puff of air come into an open foundation vent.

Plastic The Answer

Once plastics were gaining traction in the 1960's, thin sheets of vapor barrier were available. While not perfect, they did a magnificent job of blocking the movement of water vapor. Cross laminated vapor barriers that meet or exceed the ASTM E 1745 are some of the best products out there to block water vapor.

Tu-Tuf is an excellent cross-laminated vapor barrier that passes the ASTM E 1745 standard. This is what you want to use to cover the soil in your crawlspace.

CLICK HERE TO ORDER Tu-Tuf NOW.

An entire industry has evolved in the past fifteen years that specializes in encapsulating crawl spaces so the water vapor stays is the soil. When done correctly, encapsulation is an excellent way to arrest the movement of water vapor from the soil up into your home.

Puffed Barriers

Realize that other gases can escape from the soil under your crawl space and cause any plastic or membrane to puff up like a balloon. Be sure to discuss this possibility with any contractor you're getting bids from.

These same high-performance vapor barriers should be placed under poured concrete basement floors to stop water vapor movement. The same is true for any house that uses a slab-on-grade foundation. Water vapor can and does pass through poured concrete.

IMPORTANT TIP: I'd do all this mold remediation before I'd install any encapsulation product or system in the crawl space.

Stop Liquid Water

Some crawl spaces are plagued with standing water or running water in periods of heavy rain. You can stop this water from entering a crawl space by installing one of my linear french drains around the outside of your home.

Linear French Drain Streaming Video

Do your own DIY install of a Linear French Drain with Tim Carter's time-tested methods and materials! CLICK IMAGE TO ORDER NOW!

My college course in hydro-geology taught me how to capture and divert water in the soil. A linear french drain is just a gutter in the ground.

As water passes through the soil sideways through the top soil where there's air, the gravel in the trench captures the water and gravity pulls it down to the perforated drain pipe.

Many homeowners like you have used my technique to dry out their wet basements and crawlspaces. CLICK HERE to get a professional Streaming Video showing you how to STOP water problems in your crawlspace.

Column 1068

Poured Concrete vs. Block Walls

Posted on by Tim Carter
poured concrete foundation

The entire hollow spot created by the foundation addition needs to be filled with something so the concrete slab to be poured on it will not settle. Photo credit: Dave Lich

Poured Concrete vs. Block Walls TIPS

DEAR TIM: What's the difference between concrete block and poured concrete foundation walls? Which one is better? The lot I'm going to build upon has a seasonably high water table. Which of the wall systems would ensure a dry basement? Diane J., Redwood Falls, MN

DEAR DIANE: I think it might have been easier to answer a question such as: Is a glorious sunrise more beautiful than a magnificent sunset? The truth of the matter is that both building materials - concrete block and poured concrete - can yield superior foundation walls so long as they are installed correctly.

All too often builders and sub-contractors fail to realize the limitations of certain masonry materials. When this happens, foundation failures are a common occurrence.

Related Content

Precast Concrete Foundations Deserve Your Attention

Waterproof ALL Foundations - No Matter Which One You Do

Free & Fast Bids

CLICK HERE to get FREE & FAST BIDS from local foundation contractors.

Concrete Block Is Concrete!

The first thing to realize is that concrete block is made from poured concrete. The primary ingredients in concrete block happen to be: Portland cement, gravel aggregate, and sand. These are the same ingredients you'd find in a poured, or cast, concrete foundation.

The only difference between the two finished products s the size of the gravel. Typically you'll see gravel stones as large as big juicy grapes in a poured concrete foundation. A concrete block may have gravel no larger than the size of a standard green pea or a dried raisin.

CLICK HERE to get FREE & FAST BIDS on a concrete BLOCK foundation.

concrete block - foundation corner

Poured or Cast Concrete

Poured concrete foundations are solid through and through. This happens by default as the plastic concrete flows from the ready-mix trucks into the foundation forms. Poor workmanship can yield hollow spots in poured foundations. The contractors use special vibrating tools to prevent this.

The typical concrete block foundation is not solid. The concrete blocks that are used to build block foundations, by their very nature, are hollow.


CLICK HERE to get FREE & FAST BIDS on a POURED concrete foundation.

Make Block Walls Solid

When concrete blocks are stacked on top of one another, you can look down through the center of the foundation. After the concrete blocks are laid, the voids can be filled with a cement-based mortar or poured concrete that contains small pea gravel.

The concrete used to fill the block voids must have small gravel so it can flow readily into all the narrow voids. To maximize strength, the voids need to have 1/2-inch steel rods centered in the voids from the bottom of the block walls to the top. Put this steel every 2-feet on center.

If the builder does this, then the filled concrete block walls are nearly identical to poured concrete walls.

CLICK HERE to get FREE & FAST BIDS from local foundation contractors.

Both Weak If Bent

But simply doing this is not enough to satisfy me, code officials and structural engineers. Concrete and things made of concrete or cement tend to have fantastic compressive strength.

This means when you squeeze concrete it's very strong. Often it is measured in the thousands of pounds-per-square-inch range.

But the same material typically has only one-tenth the strength when you apply a tension to it. Tension is a bending or stretching force.

You can easily picture this. Imagine pouring a 4-inch thick slab that's 10 feet wide and 40 feet long that's up three feet in the air and just supported on each end.

It would bend in the center under its own weight and crack long before it would if you tried to drive across it!

Massive Soil Pressure

Backfilled soil against a wall produces tension as the soil pushes against the wall. Poor quality soil creates tension on a foundation as more and more weight is added to the foundation as the house is built.

Poor drainage around a house creates pressure as tons of water collects in the soil.

This is why roof water should NEVER be allowed to run on the ground near a foundation.

The use of splash blocks at the base of a full basement is comical. Roof water needs to be piped far away from the house to the lowest spot on the lot or into an approved storm sewer.



Steel = Strength

You can strengthen poured concrete and concrete block walls by including reinforcing steel. Often you will see horizontal steel bars placed in the lower and upper sections of poured foundation walls.

This steel is usually found about one foot up from the bottom of the foundation wall and a foot down from the top.

There are usually two rows of the steel and it's continuous around the entire foundation. When the steel bars overlap, it should be no less than 16 inches.

This steel often has a tensile strength of 40,000 pounds per square inch. This horizontal steel helps prevent vertical cracks should the foundation drop or heave.

Horizontal wire fabric can also be placed in the mortar joints between layers of concrete block to achieve the same result in a concrete block wall.

Vertical Steel

Vertical reinforcing steel is also very important. This steel can be put in both a poured concrete foundation and a concrete block wall that will have the hollow voids filled with cement grout or pea gravel concrete.

The reinforcing steel should be one-half inch in diameter and these rods should be connected to the poured concrete footer that the foundation rests upon. This steel should be placed every two feet on center.

Not Waterproof

Neither wall system will be waterproof. If you want a dry basement or crawlspace you must apply a foundation waterproofing system to the exterior of the foundation walls after they are built.

There are many different systems, but my favorite when I was building was a rubberized asphalt called Tuff-n-Dry. Once the material was sprayed on the walls it was about 1/8-inch thick. If the foundation did crack, this material could stretch and bridge a crack up to 1/4-inch I believe. The specifications may be different today.

Liquid asphalt is often sprayed on a new foundation wall. It's like a coat of paint and very thin. This is NOT waterproofing. It's just a vapor barrier.

Drain Tile

In addition, a drain piping system needs to be at the base of the wall adjacent to the footer.

This pipe is covered with two or three feet of washed gravel. The gravel is then covered with six inches of straw or a sheet of tar paper before dirt is placed over it. The straw and tar paper prevent silt from the fluffed up backfill dirt from clogging the gravel. The water that flows through the soil and makes it to the pipe is then drained to daylight if the house is built on a sloping lot. If the house is built on a level lot, the drain pipe often empties into a sump pit.

CLICK HERE to get FREE & FAST BIDS from local foundation contractors.

Column 439

Thickness of Poured Concrete Foundation Walls

Posted on by Tim Carter
Poured Concrete Foundation

The thickness of the foundation walls you are looking at are not the same. The wall below and the one to the left of the hose bib faucet are only 8 inches thick. The other walls are 10 inches thick even though there is less soil pressing against them. Why? The 8 inch thick walls are very short and they form part of half an octagon that creates a vast amount of strength. The thicker wall is straight and runs nearly 40 feet from the corner where you see the downspout. © 2017 Tim Carter

Thickness of Poured Concrete Foundation Walls TIPS

DEAR TIM: How thick should a poured concrete foundation wall be? Is it a function of the size of the house? Bob McKnight, Hagerstown, MD

DEAR BOB: The answer, although fairly intuitive, is not as crystal clear as you might think. As a poured concrete wall gets taller, it needs to be thicker. But there are many other variables that control the thickness of the wall.

A structural engineer would consider lateral loads as well as loads from the structure above. Even concentrated loads from columns and beam pockets within a wall must be considered.

CLICK HERE to get FREE & FAST BIDS from local structural engineers who'll properly size your foundation walls.

Really A Retaining Wall

To help visualize what is really happening with foundation walls, especially those that are buried in the ground, think about simple retaining walls.

Perhaps you have seen a retaining wall that has tipped over, was leaning or has cracked. The soil on the other side of a basement wall exerts a powerful force and this needs to be taken into consideration when designing and building a foundation wall.

Add Steel

To add further confusion, you also have to factor in reinforcing steel. Steel bars that are incorporated into poured concrete add enormous strength to the wall system. The placement of the steel is critical depending upon how you are trying to strengthen the wall.

Huge Soil Pressure

For example, if soil loads are significant and a house is built into a hillside, vertical reinforcing steel is a must. The pressure of the soil creeping down the hill can cause a foundation wall to develop a horizontal crack much like when you snap a saltine cracker in half with your fingers.

Vertical steel bars of a given thickness spaced a distinct distance apart and placed at a precise place within the wall can help ensure the wall will not fail. Structural engineers know exactly where the steel needs to be and how much to include.

CLICK HERE to get FREE & FAST BIDS from local structural engineers who'll properly size your foundation walls.

Recommendations

There are some basic rules of thumb for foundation wall thickness and these are outlined in many modern building codes. Poured concrete foundation walls that are less than 8 feet tall and have soil outside that is 6 or 7 feet deep against the wall can often be 8 inches thick and function quite well.

As soon as you go higher or have greater depths of soil pushing against the wall, you need to increase the thickness to 10 inches.

Pilasters / Buttresses

You may even have to put in pilasters or buttresses to strengthen long, tall walls. A pilaster is a thickened part of a wall in a short distance.

For example, a 10-inch thick wall may all of a sudden thicken to 16 inches for just a foot or so. That's a pilaster.

A buttress is a short stub wall that extends inside the perimeter of the foundation. It might be 3 or 4-feet long. It does the same job as a beam would do under a floor joist.

High-Strength Concrete

Don't forget that the concrete comes in different strengths depending upon how much cement is added at the ready-mix plant. I would use a minimum mix of 3,500 pounds per square inch(psi) mix. You can upgrade to 4,000 psi concrete if you desire, but I would only do this if it was specified by the structural engineer.

One last point: Remember that the specifications in the building code are minimum standards. You can always improve upon the guidelines you see in the code.

CLICK HERE to get FREE & FAST BIDS from local structural engineers who'll properly size your foundation walls.

Column N4

Foundation Grade Level – Don’t Go Too Low!

Posted on by Tim Carter
foundation wall

Foundation Grade Level | You can see that more than 6 inches of the foundation wall are exposed above the orange extension cord. On the right side of the photo, the foundation height is about 36 inches high. This allowed for traditional basement windows to be installed to allow air and light into my basement. I built this home in 1986. © 2017 Tim Carter

Foundation Soil Grade Checklist

  • Most foundations too deep in the ground
  • Top of foundation 18 inches above grade
  • Use excavated dirt to create an illusion of a low slope
  • 6 inches of exposed foundation minimum
  • CLICK HERE to Get Tim's FREE & FUNNY Newsletter!

Your home may be one that was buried too deep into the ground.

The builder dug the hole too deep. Based on my forty years of looking at, and building, house foundations, I'd say it happens nine times out of ten. This mistake causes all sorts of drainage problems around a house.

I've traveled all across the USA looking at foundations on houses built after WW II. Just about everyone I see is too low. There's not enough slope around most homes to provide excellent drainage.

Builders from 140 years ago in many parts of the nation, knew how high to make foundations. More on that below.

New Construction

New homes and room additions are frequently the victims of poor planning with regard to grading. I can't tell you how many houses I have seen that were put too deeply into the ground.

This condition causes marshy ground, wet basements or flooded slabs. In virtually every case, a simple drawing or calculation would have solved the problem.

CLICK HERE to get FREE & FAST BIDS from local landscapers that can grade the soil around your home.

Make a Drawing

Many modern building codes have responded to this problem. They require that the top of foundations or slabs be at least 6 inches above the highest point of soil at any location around the house.

IMPORTANT TIP: This code requirement, as are ALL THINGS IN THE BUILDING CODE, is a MINIMUM requirement. This means you can increase the distance and give your home more protection.

Visit older neighborhoods in large cities east of the Mississippi River, and you'll frequently see the top of the stone foundations was about 36 inches above the grade or soil around the home!

Builders centuries ago knew that water would cause the wood frames and siding to rot, so they wanted the house up away from splashing rain.

Sloping Away

Furthermore, the ground must fall away from the foundation at least 6 inches within the first 10 feet around the perimeter of the house. Note that this is a minimum requirement. The more slope the better.

foundation grade level

The top of your foundation should be 18 inches higher than nearby ground. Copyright 2018 Tim Carter

Using these calculations, this means that when laying out a new house, you need to pay attention to the existing grade before you dig.

positive slope away from house

Note how the ground slopes away from the house on all sides.

In fact, you need to site the house and see just what the highest elevation of the ground is at any point within 10 feet of where the foundation will be. Knowing this, you can now begin to dig the foundation.

I always made a point to put the top of my foundations 18 inches above this highest point. You would be surprised how quickly the dirt from the hole disappears when spread out around the house. Although the foundation would look high prior to backfilling, the ground had a very gentle slope once all grading was completed.

In my opinion, you can never have too much slope away from your house. My guess is that anyone who has a wet basement or ground that slopes back towards their foundation will agree.

Existing Homes

Those of us with existing houses that have grade problems face different challenges. Landscaping, sidewalks and other improvements must be dealt with in trying to correct grade problems.

If you are lucky enough to have a sloped lot, your task of establishing grade can be accomplished. It may take a small piece of earth moving equipment like a Bobcat or skid-steer loader, but it will be worth it.

If you have a situation where ground is slopping towards your house (houses built on hillsides), the trick is to slope the ground gently by creating a swale. This swale, or ditch, allows you to do two things. It gets water away from the house and at the same time collects the water which runs downhill towards your house. You direct this swale around a corner of the house and continue until the natural slope of the ground is falling away from your structure.

CLICK HERE to get FREE & FAST BIDS from local landscapers that can grade the soil around your home.

Flat Lots

Those of you who live in houses on flat ground face a more serious challenge. Sometimes the ground is so flat that there is no way to easily create a swale or sloping condition.

See the above drawing I made to see a swale.

A swale is just a small valley in otherwise flat land.

Roof Water

In these cases, you need to pipe roof water as far away as possible. Downspouts that dump water onto the ground near the house can cause serious problems. You would be surprised at the volume of water a 1 inch rainfall can produce.

You can also consider surrounding your house with a hidden moat, something like the old castles used to have. This moat is simply a ditch that is dug around the problem areas of your house. I call it a linear French drain.

Do your own DIY install of a Linear French Drain with Tim Carter's time-tested methods and materials! CLICK IMAGE TO ORDER NOW!

This trench can be as narrow as 6 inches and work. 

The depth of the trench depends on how much sub-surface water you want to collect and your local soil conditions.

In areas with heavy clay, the trench usually only needs to be 2-feet deep.

Once this trench is excavated, fill it to within 1 inch of the top with large 1 inch washed gravel. This trench acts as a collection area for surface water. As long as your soil can absorb water (even at a slow rate), you will have improved drainage conditions around your house.

Only in very wet seasons, when the water table rises around your house, will you experience problems.

CLICK HERE to get FREE & FAST BIDS from local landscapers that can grade the soil around your home.

Column B67

Replace Cast Iron With PVC

Posted on by Tim Carter

Replace Cast Iron with PVC TIPS

Tim the Master Plumber

Before we go any further, you need to know I'm a master plumber as well as a builder.

I got my master's certification back when I was about 29 years old. I've always loved to install plumbing as well as threaded black iron pipe. I cut my teeth doing many a remodeling job where I had to crack into a cast-iron drain stack and plumb in a new branch line for a bathroom or kitchen remodel job.

CLICK HERE to get FREE & FAST BIDS from local plumbers who can replace your cast iron pipes.

I discovered in no time that cast iron drain piping was durable, it was soundproof and it lasted for decades.

What's more, modern cast iron pipe is made differently than the old cast pipe. A hundred years ago they actually had molds they poured the molten iron into to make the pipe. These molds could have places where the side walls of the pipe were thinner than other spots. These thin sections could rust away.

Modern cast-iron pipe is made by spinning the metal and the pipe wall thickness is uniform.

Cast Iron vs PVC

If I were building a new home today, all of my drain lines would be modern cast iron. All my vent lines would be PVC. Watch my plumbing vent line video below to see this complex system of pipes that exists in the walls and ceilings of your home!

Plumbing Vent Video

PVC pipe is noisy. If a person flushes a toilet and the drain stack is not wrapped with sound insulation, you'll hear the water crashing against the sides of the pipe as it goes down the wall.

You'd think there's a waterfall inside your home it's so loud. You never hear this if you use cast iron.

CLICK HERE to get FREE & FAST BIDS from local plumbers who can replace your cast iron pipes.

Lanny's Question

Lanny, who lives in Campbellsville, KY, asked me a great question about old cast iron drain pipe.

"I'm going to renovate my bathroom and my main drain line for the water and sewer is the old black cast iron pipe. Is it against the code to keep the cast iron pipe or do I have to replace it with the PVC pipe?"

My Answer - You Already Know What I'll Say

Well Lanny, since it's impossible for me to memorize all the different plumbing codes across the USA, I can't tell you what the inspectors in your city would require. While there's a model plumbing code baked into the building code, cities and towns can and do modify it to their own local practices.

But here's the bottom line. Cast iron is a wonderful material. If I was building a new home today, and I plan on doing one in the next few years, it will have cast iron drain lines.

Cast iron is quiet. The issue with PVC is that when water cascades down a vertical stack it sloshes around and it's very noisy. Some who hear it think there's an actual leak inside a wall it's so loud.

It can last for hundreds of years. It's the most durable interior drain pipe you can install.

Newer cast iron pipe is made so the wall thickness is uniform. Old true cast iron pipe could suffer from thin-wall syndrome, but that's no longer an issue.

It's also easy to work with if you're creating a new branch line. You can use stainless-steel no-hub clamps to make leak-proof connections in case you want to run PVC into the cast iron.

I vote that you keep the cast iron and add new branches as needed. You can add new cast iron to old as well as blend PVC into the system if you want.

I want to add that my vent system in my new house will be PVC. But any drain line that handles water and waste flow will be cast iron.

How to Glue PVC Pipe Video

PVC Fittings Video

CLICK HERE to get FREE & FAST BIDS from local plumbers who can replace your cast iron pipes.

How to Drill Into Steel Like a Pro

Posted on by Tim Carter

How to Drill Into Steel TIPS

My guess is this summer you’ll be faced with some DIY project where you need to drill into metal. Steel is the most common metal you’ll find around your home and it’s not as hard to drill through as you might think.

Rookie DIYers will usually make a few mistakes that can cause damage to the metal, tools or surrounding finishes, cause frustration, and create a string of bad language that might cause a sailor to blush. You can avoid all of this by just following a few simple steps!

The key is to use the correct bit, drill slow and keep the drill bit COOL. You keep it cool by drilling in a puddle of clean motor oil if you're drilling a horizontal piece of steel. If the steel is vertical, you'll need a helper and an oil can to squirt oil at the base of the drill bit as you operate the drill.

CLICK HERE to get FREE & FAST BIDS from local handymen in your town to drill your piece of steel.

WATCH THIS VIDEO FIRST:

 

Degree of Difficulty: hammer-2-5

Step One: Gather a power drill that has adjustable speeds. A scrap piece of wood to place under the piece of metal being drilled will be very handy. You’ll also need sharp cobalt drill bits (CLICK HERE to ORDER some now) made to drill into metal. These bits are clearly marked for that purpose on the label and frequently contain cobalt in the steel used to make the bit.

DeWALT Cobalt Drills in case

Look at the label of any bits you buy. I've used these COBALT bits and they're fantastic. CLICK THE IMAGE to ORDER THEM NOW.

You’ll need a sharp nail or center punch tool. Metal cutting oil or standard motor oil will also be required. A clamp or two to hold the metal in place while drilling may be necessary. If drilling thin metal, heavy work gloves could prevent a nasty slice or cut. Wear safety glasses and heavy gloves when drilling steel. If a sharp shard of metal gets in your eye, the trip to the ER will cost you huge money. Take the time to WEAR SAFETY GLASSES.

Step Two: If the piece of metal you intend to drill is thin and lightweight, you may want to clamp it securely to the piece of wood. The drilling action can cause the metal to spin rapidly as the drill penetrates the metal. This can happen without warning and cause a nasty cut if you’re not careful.

Step Three: If you’re drilling a large diameter hole, say 3/8-inch or larger, you’ll want to drill smaller pilot holes first in the metal. Start with a 1/8-inch hole and then next use a 1/4-inch bit to enlarge the hole. Finish the hole with a 3/8-inch bit.

CLICK HERE to get FREE & FAST BIDS from local handymen in your town to drill your piece of steel.

Step Four: Drilling into metal, especially metal over 1/4-inch thick, can create lots of heat and friction. Heat can and will damage drill bits. Professionals use oil when drilling steel. The oil lubricates the metal and drill bit as it spins. The oil also acts as a heat sink absorbing much of the heat. Simply squirt oil on the metal before you start to drill and add more oil as you drill.

Use clean motor oil. 10w30 is just fine. It doesn't have to be expensive synthetic oil. The viscosity of the oil helps it to suck up lots of the heat from the steel and drill bit. When drilling vertical steel, you'll probably need a helper using an oil can to squirt the oil on the steel at the base of the bit. Collect the dripping oil with a container or paper towels.

Step Five: When you’ve determined where you want your hole, try to create a small depression in the metal with your nail or a center punch tool. This tiny depression helps center the drill bit so it doesn’t wander as you turn on the drill.

Step Six: When you start to drill, use a low speed and moderate downward pressure on the drill. High speeds cause too much friction and high heat levels. Slow and steady drilling speed is best when drilling metal.

Step Seven: If you notice any smoke, you’re drilling too fast or not using enough oil to lubricate the drilling process. STOP and allow the drill bit to cool. You can squirt some oil on the bit to cool it faster. Then begin to add more oil at the point where the bit is cutting into the steel.

Step Eight: When the drill bit is about to break through the other side of the metal, it can grab onto the metal causing the drill to twist in your hand or cause the metal to spin. Be very aware of this as you are about to break through the metal with the bit. Grasp the drill tightly and pay attention.

Summary: It’s not hard at all to drill through metal. Aluminum is very soft and will drill easily. One-quarter-inch steel plate is a challenge, but you can do it. Try to practice first on smaller pieces of metal. It’s vital you have a variable-speed drill and very sharp drill bits. Let me know how you do! P.S. Here's a FANTASTIC DRILL I own that I use to drill steel.

Bosch drill kit

Here's an 18-volt cordless drill I own that does a fantastic job at drilling steel. CLICK THE IMAGE TO BUY IT NOW.

 

CLICK HERE to get FREE & FAST BIDS from local handymen in your town to drill your piece of steel.

Column: HT018

Getting a New Hardwood Floor Level

Posted on by Tim Carter
hardwood floor

This is the hardwood floor, with decorative inlay, that was in my own home I built. The installer I hired used a straightedge and shingles to make the hardwood perfect. © 2017 Tim Carter

Getting a New Hardwood Floor Level Tips

DEAR TIM: I'm getting ready to install 3/4-inch-thick tongue and groove golden-oak hardwood flooring. I'm ready to start the job but my wood subfloor seems to have all sorts of high and low spots. I don't know where to start the job. Should I use a leveling compound to smooth the floor? Are there other tricks I can employ to make sure the finished floor is smooth as glass once finished? Gary W., Calgary, Alberta, Canada

DEAR GARY: This task is not as challenging as it might seem. You are very lucky that you discovered the flaw in the subflooring before you started the installation of the finished wood. All too often, I have seen professionally installed hardwood floors that have dips, humps and other inconsistencies in them. When I see these imperfections on the finished high-gloss surface, I know a rookie must have installed the actual flooring.

AsktheBuilder Podcast

CLICK this image and listen to the first call on the podcast. I talked to Jill about how to repair wood kitchen flooring, and possibly installing an inlay border as an option. Copyright 2018 Tim Carter

CLICK HERE to get FREE & FAST BIDS from local hardwood installers.

Flat Floors Are a Must

There are wood subfloors that are very hardwood-friendly. This means the subfloors themselves are flat and smooth.

Flat and smooth doesn't mean that the floor is level. A floor doesn't have to be perfectly level to look superb covered with hardwood strips.

Wood floor systems framed with engineered wood I joists, or those made from floor trusses, often are extremely flat or in the same plane. I've worked with both types of joists and they're a dream because they produce such a flat floor.

Crowns Equal Royal Pain

Those wood floors framed with traditional solid-wood joists are the ones that can cause problems. Each joist may be slightly different in height and, to compound problems, each joist can have a different degree of crown.

The crown in a wood floor joist refers to the amount of upward curvature that exists in the framing member as you look down the length of the top edge. If the rough carpenters and lumber suppliers are very selective about the floor joists they use, a traditional wood joist system can be as perfect as a wood I-joist or floor truss system.

But this is a RARITY. What's more, modern framing lumber has been hybridized so it grows faster. To me it seems modern lumber has more crown to it than lumber I used forty years ago.

The best joists are ones with vertical grain. A vertical-grain joist is one cut from the center of the tree. It would have the small dark round center of the tree in it and the growth bands radiate out on each side until you get each end of the joist. A flat-grained joist is one that's cut from, or near the edge of the tree. 

If you’re interested in learning more about cost estimates for hardwood flooring I have an article here.

Get Floor Ready

To get your wood subfloor ready, the first thing to do is to make sure the wood sheathing that is on top of the joists is securely fastened. I highly recommend installing coarse-threaded screws in addition to the nails that might already be in place. Be sure to do this in high foot-traffic areas of the room. The use of screws will prevent floor squeaks that are caused by nails that are not driven completely or that work themselves loose because of lumber shrinkage. Use screws that penetrate at least one and one quarter inch into the wood joist.

After the subflooring is screwed tightly to the joists, vacuum the floor to remove all dust and debris. Use a six-foot long straight edge and a level to find the highest spot on the floor. Although you might want the floor to end up in the same plane, it may not be a realistic goal. Your existing floor may be severely crowned. If this is the case, the hardwood floor may need a giant wedge of shims or leveling compound that extends to one or more walls in the room. This degree of correction may not be needed to get the visual goal you desire.

CLICK HERE to get FREE & FAST BIDS from local hardwood installers.

Filling Low Spots

I always use regular roofing shingles to fill in any dips or depressions in wood or concrete subfloors. The overall floor may not end up in the same plane, but if you have just one gentle hump that extends over 10 or 12 feet, the naked eye can rarely detect this imperfection. Dips or depressions in a subfloor are immediately identified using the six-foot long straightedge. Place it at the highest spot in the floor and slowly swing it around in a 360 degree circle. The low spots will be readily visible under the straightedge.

You can see all imperfections best in a darkened room. Use a flashlight held parallel with the floor and aim the beam at the straightedge. Believe me, you'll see gaps beneath the straightedge.

Use a marking crayon to outline the hollow spots and mark how deep they are.

Use as many asphalt shingles as necessary to fill the low spots. They do not have to be nailed down as the many nails used to hold the flooring in place will pass through the shingles as they are driven into the wood subfloor. You can tack the shingles in place if you desire so they do not move around as you work on the floor.

Floor Leveling Compound

The use of a floor leveling compound can achieve the same goal, however it requires a bit of skill to apply the compound evenly. Also, if you mix some leveling compounds wrong by adding too much water, there is a possibility they can break down over time and turn to powder. These compounds work great if you follow the instructions. 

Always mix a TEST batch and see how it works. This is a cheap insurance policy. You want to make sure it flows and looks superb.

You want to know how THIN you can get the self-leveling compound. Some are not recommended for thin hollow spots. READ the label to find out the limitations of the compound you decide to use.

This will not happen with shingles, which is exactly why they are my weapon of choice when confronted with this task. But shingles can be hard to work with and they don't fill the entire hollow spot. There's pros and cons with each method.

This is a great name-brand self-leveling floor compound. You just mix it with water and pour. CLICK THE IMAGE NOW TO ORDER IT.

Tongue Depression

If you fail to fill the depressions under a hardwood floor, the hardwood can flex when you walk over it. Over time, this can cause squeaks as the hardwood slides up and down the nail shafts of the nails used to install the hardwood. The subfloor doesn't have to be absolutely in the same plane to prevent squeaks, but voids of 1/8 inch or more can cause problems.

In thinner hardwood, the actual interlocking tongues can crack off if the hollow spot is too big. This is a massive problem and is why you must have the floor FLAT.

Installing hardwood flooring perpendicular to the direction of the floor joists is also critical. Finished flooring that runs parallel to the joist direction will often telegraph the slightest defects in the subflooring.

Be sure to install tar paper over both wood and concrete subfloors to minimize moisture infiltration to the underside of hardwood flooring. Tar paper is an excellent vapor retarder.

CLICK HERE to get FREE & FAST BIDS from local hardwood installers.

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