Every now and then, I stumble across a very interesting product. It appears that it has happened again. Fiber cement siding products are simply a magnificent alternative to conventional wood siding products - plain and simple.

The thing that is amazing about fiber cement is that it is not a new product. I have actually worked with the material for many years. Here in Cincinnati, you can drive through the older neighborhoods of Fairmont, Clifton, Norwood and Price Hill and find vast quantities of the material. Based upon the style and types of older houses you see it on, it apparently was a very economical material back 90 years ago. The good news is that it is still a very economical building material.

Concrete Roots

Portland cement was discovered in the 1800's. It didn't take long for inventors to find that it had lots of different uses besides a paving material. It made perfect sense to blend the cement paste with fine fibers and create an "armor" plate - like siding. After all, house were constructed with rock for years. Why not nail on thin sheets of rock? I sure wish I had thought of the idea!

Nails Without Splitting!

You would think that thin pieces of fiber cement siding would readily split when you drive a nail through them. It doesn't happen - unless you nail very close to an edge. Wait till you try it. You will be amazed at the ease of installing this water, fire and insect resistant building material.

If you choose to use fiber cement siding, it installs just like regular wood siding. There are a few exceptions - basically, you can blind nail this material very similar to the manner in which vinyl siding is installed.

Installing any siding correctly is becoming a lost art. Ninety nine percent of the installations I see are being done incorrectly. The siding installers seem to think that the siding will make the house/structure waterproof. Nothing could be further from the truth. Seams and butt joints between siding and trim are all excellent locations for wind driven rain to enter. This water will readily begin to rot the sheathing and your structural wood members.

If you ever have the luxury to partially demolish an older home built by old craftsmen you no doubt will run into some tar paper. Tar paper was the only water repellent available for the old timers to use. But guess what? It was very effective. Tar paper was used under old fiber cement siding, traditional wood siding and stucco. You need to use it under your new fiber cement siding at the very least. A better alternative is to use a moisture and air infiltration barrier. These products are easier to apply and offer great energy savings potential. If you choose to use tar paper, remember that you work from the bottom up. Each successive piece must overlap the one below. This is how water is shed to the bottom of the structure. Don't forget that your first piece should extend 1/2 inch over the top of the foundation. This will ensure that water will not roll back under the sill plate and into your basement or into your house should you live on a slab.

Trim First - Siding Last

Installing siding is a multi-step process. The fun part of actually applying the siding is usually the last thing you do! The first thing you must do is apply all of your inside and outside corner boards, window trim, starter strips and flashings. Once all of this detail work is complete, you can finally install the siding. Currently, the major fiber cement siding manufacturers do not have thick fiber cement trim boards available. I'm told this is a future possibility. As such you are forced to use wood trim or vinyl. Either material will do fine. To get long lasting results with wood trim, it is absolutely necessary that you backprime the wood BEFORE installation. Backpriming simply means that you must paint all surfaces, edges and ends of the wood before it is installed. It is actually preferable to paint it with two coats. When final cuts are made, these fresh cut ends need a coat of paint just before the wood is nailed into place.

Caulk & Flashing at Butt Joints

Because siding pieces only overlap one another 1 and 1/4 inch or so, butt joints (where two pieces of siding butt against one another) are highly susceptible to leaking. The manufacturers recommend that you caulk these butt joints. That is a good start. I urge you to cut small pieces of 30 # felt paper to act as a flashing. These strips of paper need to be two inches wide and two inches longer than the width of your siding material. As you nail the end of your first piece, slide a felt strip in place so it is up 1/4 inch from the bottom of the piece you are installing. One inch of the felt should be under the piece you are nailing. The remainder that is exposed will be covered by the abutting piece of siding.

Nails

Spend the extra money and use stainless steel nails. These nails are less prone to bending as you nail. Also, you never have to worry about rust!

Specific Installation Instructions

No matter who installs your fiber cement siding or panels, you MUST obtain and read the installation instructions. Each manufacturer has different ways to install their product. The process of reading the instructions may take only 1/2 hour!

If you hire a contractor to install the siding, make periodic visits to ensure that the job is being done right. Remember, the contractor can't see your house from his!!! Mistakes and leaks will not bother him.........

Column B185

Fiber Cement Products - Descriptions

I called all of the fiber cement siding manufacturers prior to writing this Builder Bulletin. Can you believe that I only received materials from two (FCP and James Hardie) of the companies? Human error was to blame no doubt. I am sure that you will have success when you call. The materials/samples I did receive are most likely VERY representative of what is out there. Let's start with the standard fiber cement siding.

Fiber Cement Siding

Both of the siding manufacturers make this product in a 5/16th inch thickness. The widths range from six inches all the way up to 12 inches. All pieces are 12 feet long. This allows you to recreate many different looks with respect to exposure. The only disadvantage in dealing with the larger widths (10 and 12") is that you often are not allowed to blind nail these products. I happen to like the blind nailing concept. It allows you to completely hide the nails. What a smooth, clean look you end up with!

As for patterns, you can get smooth, woodgrain, colonial smooth and colonial rough-sawn. Not all widths are available in all textures/patterns.

Some of the manufacturers offer their products pre-primed from the factory. You may find that this is an attractive option, especially if you are building during the wet/cold season.

Fiber Cement Panels

Do you know someone who has a newer Tudor style house? I'll bet they are having problems with rot in those pressed wood panels! Guess what? They can be replaced with fiber cement panels! How about T-111 panels? You know, those are the rough-sawn panels that have vertical channels every four or eight inches. These are also available in fiber cement. Stucco-look and simple smooth are also available. The panels are 5/16th inch thick. They come in four foot widths and in eight, nine and 10 foot lengths.

The panels are joined together using special vinyl trim pieces that are called for by the manufacturers. You CANNOT use aluminum trim! The alkaline chemical compounds in the fiber cement will eventually cause the aluminum to corrode. Don't be tempted to use aluminum!

If you are building a new home and want the Tudor look, then you MUST use the fiber cement panels. As long as you prepaint the panels and all of the wood trim pieces before assembly, you will have a virtual maintenance-free exterior!

Soffit Panels

These are basically identical to the siding panels. However, they are a tad thinner. The soffit material is 1/4 inch thick in most cases. It comes in either smooth or woodgrain texture. Soffit panels are available in eight foot lengths with 16, 24, 36 and 48 inch widths.

Cutting the Material

You have three choices. You can use a circular saw with a carbide blade, a guillotine cutter (similar to those used to cut vinyl tile) or a power shear. The power shear and guillotine are dust free. Carbide saber saw blades allow you to cut curves and circles.

Column B185

Cement Siding Manufacturers

Cement siding is a most interesting product. It has been around for over 100 years, very much like cork flooring. It gained widespread acceptance as many row houses used it to resist "frost, fire & ants." Those claims are so true! I know of 15 houses within three miles that have it on the sides and roofs of the houses. What is mind-boggling is that the material has been in place since 1910 or so! The houses that have it as siding show no signs of blistering or peeling. If this isn't a reason for you to check out all the manufacturers listed below, then I don't know what is!

Based upon research materials sent to me just before writing this bulletin, one of the manufacturers clearly leads the pack in volume. That company is the James Hardie Building Products Company. Their U.S. capacity is approximately 900 million square feet of siding per year. Now mind you I didn't say that bigger is necessarily the best. That kind of production allows them to service demand.

I urge you to research all of the companies listed below. You will (hopefully!) find just what you are looking for. There is a very good chance that you will be able to readily obtain the product through a local lumber yard. Don't count on any of the home center stores... I doubt that they would stock or order it in. However, if you find that I am wrong on this point, don't hesitate to contact me.

Column B185

Fiber Cement Siding Accessories

If you want to make sure that your fiber cement siding job is as maintenance free as possible then you MUST also call this company. They make specialized high quality vinyl trim pieces that compliment and fit cement siding, soffit pieces, and panels.

This company is an authorized manufacturer of vinyl trim pieces that fit James Hardie Fiber Cement Products. They have very nifty inside and outside corners, vinyl splicing H-channels, Z Flashings for panels, and very cool continuous soffit ventilation strips that couple with the fiber cement soffit panels.

NOTE: You must have the vinyl trim in place or you may VOID your siding warranty!

Column B185

I'll bet you have seen houses that have fiber cement siding or shingles. The best place to see them is in older parts of your town or city or those sub-divisions built in the 1950's or 1960's. The shingles look like large sized armor plating. The houses that are in the older parts of your town may be up to 100 years old. If you are lucky you may spy one that has never been painted. In these instances the shingles will have a multi-colored look upon close inspection. What a cool product! One that has truly passed the test of time.

Installing Fiber Cement

These products are installed in the same manner as any exterior siding product whether it be wood, vinyl or other siding. It is simply nailed to the exterior walls. My initial reaction when I first came into contact with this material is that it would crack when you nailed it. Not so! The older fiber cement that is 100 years old is brittle, but not the newer products. Sure, you can crack it if you hit it hard enough, but you will be surprised how well nails go through it.

Water Barriers

When I drive by certain new home construction sites I often get cold chills. I am shocked to see carpenters install siding products directly over exterior sheathing with NO water barriers between the exterior siding and the plywood, OSB or foam sheathing. This is a huge mistake in my opinion. Even a superior product like fiber cement siding or shingles can allow water to get past a butt joint or where it touches up against doors, windows or corner boards. Water barriers like traditional tar paper or the newer air and water infiltration barriers are a must. Carpenters from generations ago discovered that tar paper absolutely kept wood sheathing dry. I can vouch for this. Many older homes that I took apart in order to add a room had tar paper under the siding that was brittle but it still stopped water! Make sure that a water barrier is part of your installation. I don't care what the building code or the carpenter says!

Cutting Fiber Cement

This is probably the most difficult part of the job. You can use a regular circular saw with a carbide tipped blade, but you better have a dust mask. This method creates lots of dust. The dust will eventually ruin the bearings in the saw, so use an old saw if you must go this route. You can use an electric shears if you want to avoid dust. The tool is primarily used by professionals as it is fairly expensive. It is definitely not a tool to use for just one weekend. There is a good possibility that a tool rental center might have one if you just need it for several days. Check out the web site of Pacific International Tool & Shear for more information about this tool.

Painting

The newer fiber cement panels need to be painted. They don't have the cool built-in color of the 100 year old products. the good news is that these products hold paint exceptionally well. The fiber cement is very dimensionally stable and simply doesn't expand or contract. This means paint will hold on for a very long time. I would paint the product with the new paint I discovered that contains polyurethane. It is Weatherbeater Ultra, sold at Sears. Make sure that the fiber cement siding is nice and clean and dust free before painting.

Fasteners

Always use the best nails when installing fiber cement. If you can find stainless steel nails, use them. If not, go for the hot dipped galvanized nails. Some installers will use nails driven by air nailers. These are galvanized, but most do not perform as well as hot dipped galvanized.

Keep in mind that some fiber cement products can be blind nailed. This is a good thing! Blind nailing is the way most roof shingles are installed. In other words, you don't see the nails. Consider selecting a fiber cement product that can be blind nailed. This will eliminate all sorts of problems you can often have with exposed surface nails. Always read the installation instructions and use the nails that the siding manufacturer says to use.

Column B327

Old Styled Fiber Cement Siding

I don't know how many old houses out there have the original fiber cement shingles but my guess would be in the hundreds of thousands. If you were at my house, within 15 minutes I could drive you past houses that have had these durable products in place for nearly 100 years!

Some of the houses have never had one thing done to the exterior. If they were simply cleaned, they would look as they did at the turn of the last century. It makes sense when you think about it as the material is simply thin layers of rock!

So who still makes these old styled shingles? It is a company more know for its roofing than fiber cement products. It is GAF Materials Corporation.

The Three Profiles

These old styled shingles not only match old houses but they look swell for new installations. There are three patterns and they are fairly distinctive from one another.

Purity

This shingle is available in three different bottom edge styles. You can get it with a straight, wavy or thatched bottom edge. All of the shingles measure 24 inches long or wide by 12 inches high. The normal exposure is 11 inches for the straight and wavy bottom and 10.5 inches for the thatched bottom edge.

Profile

This shingle has a straight bottom edge and comes in two sizes: 12 inches high by 24 inches long or 14 5/8 inches high by 32 inches long.

Emphasis

A thicker thatched edge shingle 14 5/8" x 25 5/32".

Column B327

Complete Listing of Fiber Cement Manufacturers

Within the past three years, there has been some consolidation within this industry. Some companies have merged with others. The bottom line is that fiber cement products are readily available in most markets and they are usually fairly easy to obtain. My biggest complaint is that some manufacturers do not yet offer a complete package with respect to trim pieces. In other words, when you install siding you often need to deal with inside and outside corners, facia and rake boards, drip cap, soffit terminations, etc. If I were making fiber cement siding, I would want to offer all of these optional pieces and maybe even other decorative trim made from fiber cement. As it stands now, in certain instances you need to substitute wood or vinyl products to complete the exterior installation. This isn't all bad, but you may have some problems with respect to texture differences. Be sure to ask about accessory and trim pieces when you are deciding what product to use.