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Foundation Drain Tile Installation

Drain Tile

The builder is doing just about everything right installing this drain tile. The drain tile is the white pipe next to the footer. He should have 2 or 3 inches of gravel under the pipe. If the pipe has two rows of holes, they should point down in the 4 and 8-o'clock position. Finally, he should cover the drain tile with about 2 or 3 feet of gravel, not 3 inches like you see. He did put the pipe alongside the footer instead of on top and he's covered the gravel with tar paper so it doesn't get clogged with silt from the backfill soil. Copyright 2017 Tim Carter

"The basement, before the house is built on top of it, looks just like the typical in-ground swimming pool. Once the house is built, this swimming pool gets covered."

Foundation Drain Tile Installation TIPS

Foundation drain tile systems are one of the most important aspects of residential construction if your home has a full basement or crawlspace.

Drain tile systems are also one of the most misunderstood parts of the average home - both by most uninformed builders and homeowners.

Related Links

Foundation Waterproofing Systems and Tips

Water Sitting Around Shallow Foundations

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Where Is Drain Tile Placed?

Drain tile is placed deep in the ground alongside the foundation footing.

Because these systems are usually deeply buried and cannot be easily modified or corrected, it's vitally important that they are installed correctly. Foundation drainage systems which are installed properly can serve a dual role.

Drain Tile Pipe Video

Watch this video to see the correct white PVC pipe to use and the orientation of the drain holes.

He doesn't show this pipe along a foundation but what you see are the first three steps of doing the job right.

Foundations Are Covered Swimming Pools

Many homes around the nation have full or partial basements. These basements are really reverse swimming pools.

The basement, before the house is built on top of it, looks just like the typical in-ground swimming pool. Once the house is built, this swimming pool gets covered.

But most people don't want water in their basements. Foundation drain tile systems are the means by which groundwater can be transported away from your basement. If you want a dry basement, you must have fantastic drain tile and waterproofing on the outside of the foundation.

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

Is There Water in Soil?

There is water in the soil. Thousands of gallons of water can be in the soil on your lot.

The water content in the soil surrounding your house can fluctuate seasonally. There's always a point at which you can dig and hit water. Geologists often refer to this as the water table.

This water table rises and falls in response to the amount of precipitation in any given time period. The water table in many parts of the country can rise to within a few feet of the surface during wet spells.

How Does Water Move Through Soil?

The water in the soil is moving all the time. In almost all cases, it moves down a few inches then it begins to move sideways. Gravity is pulling it to the oceans around the world.

drain tile

Here's a side view of a typical house. The black clouds release rain. It falls into the soil and starts to go down, but then sideways. The bedrock under the soil generally, but not always, follows the shape of the soil above it. Soil depths can vary from several feet to tens-of-feet thick. ©2017 Tim Carter

Most people think that the water in soil moves straight down but in reality, it moves sideways through the topsoil and upper layers of the B horizon of soil.

Almost all homes are built on some sort of slope, so if you have acres of land above your home, the water in the soil is all marching and flowing towards your house.

Does Water Take The Path Of Least Resistance?

Water will take the path of least resistance. It can choose to go sideways through a crack in your foundation, or it can go down alongside your foundation through clean, washed gravel into a pipe.

I'm sure that you will agree that it is a better idea for the water to go down the pipe.

How Many Parts are There to Drain Tile?

A foundation drain tile system has four main components:

  • Drain tile pipe
  • Gravel
  • Gravel Protection
  • Water outlet

All of these elements must be installed for the system to function properly.

drain tile

Here are three of the four parts of the system. The missing part is what happens with the round drain pipe. It will either extend sideways to daylight if the slope is steep around the house, or it will go under the footing to a sump pit in the basement or crawlspace. (c) 2017 Tim Carter

How Big is Drain Tile Pipe?

The drain tile or pipe is usually 4" in diameter and is perforated or has pre-drilled holes along its length. Depending upon the type, it can be purchased in rolls up to 250' or in 10-foot sections. Fittings are available to allow you to go around corners or interconnect the pipe.

I've never been a fan of the rolls of black corrugated drain tile with the slits in the cracks. I prefer the more rigid white plastic pipe with two rows of drainage holes drilled into the pipe.

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

How Much Gravel is Needed?

Install at least at least 2 or 3-foot thick layer of gravel over the drain tile. More is better.

The filter media or gravel is used to cover the drain tile. Water can flow readily through this gravel and find its way to the pipe.

One customer wanted me to ensure his room addition basement never had water in it. He was willing to pay to have the high-side foundation wall that pointed upslope filled completely with the nice rounded gravel.

There was no way water was going to ever try to force its way into his basement when it had the chance to go straight down to the drain-tile pipe.

Remember, water takes the path of least resistance. Some soils, heavy clays, resist water movement.

What Type and Size Gravel?

The gravel that is used most often is large 1 - 1 1/2" diameter washed rounded gravel. This gravel is about the size of a walnut or large grapes.

Some parts of the USA have crushed gravel this size. It's not rounded, but that really doesn't matter. All that matters is that you just put in this rock and no sandy gravel. Sand slows down the movement of the moving water.

If your soil is like this, the water would rather go sideways into your basement than down through the clay soil to the drain tile.

How Do You Protect the Gravel?

You must protect the gravel with a barrier. It prevents silt and mud from the soil from clogging the gravel or the drain tile pipe.

During excavation, dirt removed from the hole is fluffed. This means that it is disturbed and broken up.

It's volume usually increases about ten percent. It's loosened and disturbed more during backfilling procedures.

Does Gravity Compact the Backfill Dirt?

As the soil gets disturbed, small dirt particles, or silt, are created and separated. These are carried through the gravel by the rainwater or snowmelt which enters this soil.

Very few builders take the time to compact the soil around the outside of a house so Mother Nature does it using water and gravity.

Without a barrier of some type covering the clean gravel, these silt particles immediately clog the gravel and drain tile and render it useless.

IMPORTANT TIP: Most builders often do not install this barrier. It's a HUGE MISTAKE to eliminate it. Do NOT ALLOW them to tell you it's not needed. They're either ill-informed or lying to you.

What Material Covers the Gravel?

The materials commonly used to stop the silt from getting to the gravel are straw or tar paper.

If you use straw, just scatter a 16-inch layer on top of the gravel before you put in any soil on top of the gravel.

Tar paper is easy as you just cut the correct width and lay it on top of the gravel.

Where Does the Drain Tile Pipe End?

The water outlet is simply the place where the collected water flows to. It can be one of two places:

  • Daylight - downslope from your home
  • Sump Pit - inside a basement or crawlspace

If you build on a hillside, your drain tile will simply 'daylight' or come to the surface. This happens naturally because the drain tile pipe is installed nearly level and as the ground falls away from the house at some point the pipe will be visible.

This is the best situation because your system depends entirely on gravity to work.

Are Sump Pumps a Good Idea?

No, sump pumps are a bad idea.

If you build on level ground, you have to install a sump pit. A sump pit is usually installed inside the basement of your home.

The pit is nothing more than a buried plastic container that resembles a garbage can. It's large enough for a sump pump to rest at the bottom.

The drain tile pipe runs beneath the footer to this sump. The collected water is then mechanically pumped from the sump.

Do Sump Pumps Fail?

Yes, sump pumps stop working and the basement or crawlspace floods. They typically fail in big storms when there are extended power outages.

Sump pumps also fail because the float mechanism gets jammed or the pump burns up.

Dry Wells Don't Stay Dry

Some people say to extend the drain tile pipe to an underground dry well. A dry well is a large subterranean pit filled with gravel.

The drain tile pipe runs to this pit and the water fills this pit.

These pits work well only in places that have very open gravel soils. Not many places have this soil. In most places, the soil is dense clay and the dry well fills with water and the water then backs up against your foundation. 

Should Drain Tile Be Next To the Footing?

Drain tile pipes work best when placed alongside a foundation footing, instead of on top of the footing.

By placing the pipe alongside the footing, you lower the water table below your basement floor another 6-8 inches.

When Should Drain Tile Be Installed?

In new construction, install the drain tile immediately after the footing forms are removed. Cover the pipe with gravel to a level flush with the top of the footer.

If you choose to wait until the foundation is poured, there will be less room to work in, the side walls of the excavation could cave in, or extra concrete from the foundation pour could fall into the hole and have to be removed. Believe me, it's faster and easier to install the drain tile pipe and the first layer of gravel without the foundation walls in the way.

Install Piping After Waterproofing

After the foundation walls have been waterproofed you begin step two. Backfill over the pipe with at least a three-foot-thick layer of gravel.

If you can afford it, backfill with gravel to within 18" of the finish grade. You must think long term. Remember, it will be virtually impossible to dig up and add gravel in the future when your basement is leaking. The extra money spent now is well worth it.

Once the gravel is in place, cover it with a 16-inch thick layer of straw or a single layer of 15# roofing felt paper. This barrier will prevent the silt from the backfill dirt from clogging the gravel and drain tile.

Extra Protection

To really ensure your basement or crawlspace stays dry, install a Linear French Drain around your home once it's built. I created a fantastic step-by-step DVD showing you how to do this.

Linear French Drain DVD

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

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

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Foundation Drain Tile Often Installed WRONG
Foundation drain tile is installed wrong by most builders. They don't understand how water moves through the soil.
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39 Responses to Foundation Drain Tile Installation

  1. I am wondering if a French Drain would help solve the water problem in my crawl space. My house was built late 70's. For whatever reason, the crawl space floor is lower than the yard on the exterior of the house. The back yard does slope towards the house, which helps bring extra water into the crawl space. Basically, they did dig a trench around the interior foundation of the crawl space, to direct water to the front yard corner of the crawl space. At this time, we siphon the water out as it accumulates. I am sure a crawl spacea sump would help as well, but I may not need that at all if a French Drain would work. Please let me know your thoughts. Thanks so much.

    • Damon, your question requires lots of typing, plus I have some questions for you so I can give you the correct answer(s). I only do pithy answers here in the comment section. If you want to protect the investment you have in your house and not waste time or money *hoping* you make the right decision, you should talk to me on the phone for just 15 minutes. It'll be the best investment you've ever made in your home!

  2. The drain tile entering my 24 inch deep pit are 1 inch from the bottom. My pump doesn't engage unroll the water level is 2 inches above the tiles. Then it takes up to 3 minutes to pump out the back logged water. Should this be changed?

  3. I need to redo/install new drain tile for my mother. I know and have found all the basics and done extensive research on what are the best ways to do it, what the best tools are, what pipe and gravel and gravel cover to use etc....however...I absolutely cannot find ANYTHING about the drain tile for a split level home. I need to know what to do where the sub basement drops to the lower basement. Do I just run a pipe straight down to the next level or does it need to be on a small angle??? Or is it different all together when it comes to a split level home???

  4. Tim,
    My home was built in the late 40's early 50's using a concrete foundation. the problem is water leaks in thru the corner walls some springs. last spring it was 5 bucket fulls, this spring it was just a bucket full & some springs none at all. i notice i have two sump pits with one pit having a pump. i looked into the pit the other day wondering why this thing isn't draining and i noticed there is not any drain tile or pipes running into either pit but both have water in them. i don't understand were the water is coming from in the pits or why i am leaking.

  5. I want to install drain tile in an old limestone basement. The rule is 6 inches away from the wall along the footer. I have an old lime stone foundation that has no footings. Could I start breaking concrete 6 inches away or do I break concrete next to to the walls and lay the drain tile along the walls. My fear is would the foundation give if I break concrete alond the walls. I never have installed on a limestone foundation and this is for inside the basment. Thank You

  6. We are in a building that is suppose to have a drain tile around the outside of the entire footing and then go to a sump pump for expulsion of water. We have found out that only a small part of the tile was put in at the time it was built. We have a finished basement, and would like to have someone dig it up and properly install a drain tile around the outside of the footing, as our city code calls for. Who would I be trying to hire for a job like this? Any info you can supply would be greatly appreciated!

  7. Is it best to place interior drain tile around the entire perimeter of the house? Someone suggested we only do it on what would be considered the "upstream" side.

  8. I am going to build a house in Morelia mexico and on sloping (18"/10ft). The rain is very heavy july and August and dry the other months. bedrock is 6 ft deep on the high side and 8 ft on the low side. 6" deep cracks at end of dry season. I am going to use fill with crushed volcanic local rock (local) to 3 ft above the high side for the slab and the stepped footing 38" into the clay soil with block to slab level. Question: do I drain tile the outside footings or set piers at the intersections of the bearing walls to bed rock? which is less effective? or is there another way?

  9. I have a 1960's brick rambler on a septic system, with a sump pump. During a recent week of heavy rains, the drain outside the basement door had water coming up through it. None of the drains inside the basement were flooding. Any thoughts as to what the problem could be?

  10. I have a room in my basement that is finished and it does not have drain tile is it possible to put drain tile about 8 inches away from the footing and then I could hook it to my old drain tile that is in the rest of the house. would this work

    thanks tim

  11. I have two problems during the wet season, leakage at the wall/floor interface, and small amt of water from cracks in the foundation walls. I also have window wells that fill up during heavy rain(not from the top, they continue to fill over the next few days). My sump pump is working. My question is, I have a 1948 home with poured concrete walls. Is there anything specific about this era of home that needs to be addressed, or does this sound like typical basement leakage?

  12. I have a 150 year old home in Chicago. The foundation was dry-poured. The walls were seal coated about 20 years ago and faced with foundation insulation. It is still subject to seepage during heavy rains.
    Can i install the perforated drain tile outside and connect it directly to my main drain to the city sewer system to carry the water away?

    • Check the codes there, I would imagine it is the same- in Minnesota you can not connect drain tile to the sanitary sewer system. Cities do not want to deal with all of the water you would be adding to the system.

  13. I have a working drain tile system in my basement. The two sump pumps kicks on constantly during heavy rain, but for some reason my basement floor still gets wet considerably. I have lots of cracks in my basement floor and water comes through what can i do? Thanks

  14. I have a waterproofed basement. It was done 15 years ago with a local company and is an interior French Drain System. I had my first problem a year ago. The company came out and we found out we do not have a footer. Water came in from under the wall and carried mud and silt which slowly traveled thru the gravel and clogged up the slits in the drainage pipe. They cleaned out the gravel, put in new pipe and sealed with concrete. Here we are a year later with same problem. I have diverted all the water on the outside away from the house. The back corner is where the problem is. Any suggestions?

  15. I bought a home a few months ago and just noticed that the drainage pipe from the tiles leading into the pit is sloped upward at a 30 degree angle - half of it on one side of the opening and the other half into the sump pit. This inspector did not pick it out. Is this a flaw in design?
    By the way, some water does make it into the pit and it does get pumped out when a good amount has accumulated.

    • Forever..... Go up to the top of the comments and BOTTOM of my column above. See my DVD about Linear French Drains??? BUY it to discover how to have one MUD-FREE for life.

  16. Water takes the path of least resistance, which means if you don't line the dirt wall with barrier until you get to the top, it's still going to fill with silt even if you cover the top... just like a retaining wall. You must put barrier all the way from bottom to top, or the path of least resistance, as you said, is horizontally into your gravel, with the silt in tow.

  17. we have a drain pipe that goes through the foundation into the crawl space, this is supposed to be connected to the tile drain around the house, which my understanding, is that it has an overflow to our sump pump. No we are not in a flood plain, no hills around us, highway close by and it would have to flood up to the bridge plus before we would flood! But we have this pipe, just in case??? It creates moisture in an area that should be moisture free. We have standing water in the middle on top of the plastic. The builders superintendent has put a dehumidifier under there and as the bucket fills up my husband has to dump it! But he travels and I'm not crawling under there to do it. The problem I see is the water has not gone down! Why this superintendent has not used a shop vac or other suction to get the water out is beyond me!!! I'm trying to be PC here, but being stretched to my last string! Any ideas!

  18. We excavated for an indoor sport court. The room is 21' below grade. We are still in construction phase, but past framing and mechanicals. Our court continues to take water in from the outside, and more concerning is the amount of mud/silt accompanying the water. The sump pit has been cleaned out multiple times. Debris and gravel have caused multiple pump failures (and replacements). The problem has been occurring for months. We are concerned about the process followed during construction. Any ideas what could be causing our problem, and, how to confirm issue and correct? Thank you,

  19. I live in Chicago in a 1920's bungalow . For 16 yrs the basement stayed dry. We do not have a sump system. Recently the basement flooded coming up mostly thru the two floor drains. We diverted the downspouts, riddled out the line to the street and put more dirt around house. After a mild rain a day later some water came up the drain which we had put floats in. Wondering where the water is coming from- ground water seeping.? What is a possible solution?

  20. We recently bought a 4 unit apartment building, built on 1904 with rock/cement foundation. We have noticed pin hole leaks, we also had a drain pipe under ground break and found our soil is saturated. We live at the low level on a corner were everyone's water drains to us. What do you suggest? Also we are doing the work ourselves if that makes a difference.

  21. What determins if the footer tile goes inside the crawl space or the outside footer. block and brick house slope away from house

    • Tyr,

      I'm going to assume you got an incoming phone call or were otherwise distracted before you finished reading the above column.

      I suggest you go back up and re-read it to understand why it's better to have a home that doesn't rely on a sump pump.

      I clearly state that the best situation is a sloped lot where the drain tile extends to daylight.

  22. I'm installing 4" pvc drain tile around the footings of my foundation with a 60' run of solid 4" pvc pipe to daylight.
    It will have at least 3 clean out ports installed to permit maintenance, tree roots and so on.
    My question is should I cement /glue the pipes/fittings together?

    • You need to use schedule 40 pipe or at the very least SDR-35 and NO 90-degree fittings at all!

      SDR-35 comes gasketed. You BETTER READ my past column about tree roots and sewer lines!!!!

  23. I recently bought a house where my crawl space kept getting water in it. After alot of yard drains n french drains it still didnt fix my problem. So I dug up the foudation, waterproofed, then put drain beside footer to daylight. I then backfilled with washed gravel all the way to the top. Will this be ok or do i need dirt on top of the gravel?

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