I have been researching siding options for months, trying to find the most sustainable siding option that will fit into our budget. For us, picking a siding comes down to cost, ease of installation, maintenance and durability, and its impact on the environment. I was trying to find the perfect siding that will do the least harm to the environment, will help protect our house from water damage, and that we can afford. What I found was a pretty hard decision. After months of research, I have concluded that there is no perfect siding material, yet. There are pros and cons with every type of siding and after weighing all of those, we will likely choose engineered wood siding for our home renovation.
What is Engineered Wood Siding?
Engineered wood siding is comprised of wood strands cut from a sustainably harvested tree that go through a resin, wax and treatment process. The strands are compressed to form a structurally stable piece of engineered wood. Due to the treatment process, the boards are rot and termite resistant. The siding comes in clapboard (also called lap siding), shingle, vertical, and panel configurations. They come in cedar texture finishes as well as smooth finishes. The siding comes pre-primed and can even be pre-finished with paint.
Engineered Wood Siding Pros
Durable – The siding is marketed to withstand hail, windblown tree branches, baseballs, you name it. Vinyl and fiber cement on the other hand are a lot less durable. Vinyl cracks easily since it is a thin plastic. Fiber cement can also crack due to freeze/ thaw cycles and impact from objects.
Termite and Rot Resistant – The zinc-borate treatment makes the engineered wood siding termite and rot resistant which increases the lifespan of the material. This is especially useful for areas of the country that have major termite issues and in locations where moisture is a constant threat to building materials.
Cost Effective – I was pleasantly surprised to see that the cost of engineered wood siding is on par with fiber cement siding. It is less expensive than cedar lap siding. Only vinyl siding and pine and other softwood lap siding are less expensive options than engineered wood siding.
Lightweight – A lightweight material is much easier to handle and therefore quicker to install than heavier materials. The boards are actually lighter than some solid wood siding. The siding installer will appreciate the ease of lifting the boards into place.
Easy to install – Engineered wood siding can be cut like solid wood siding meaning no special tools are required In contrast, fiber cement siding requires special tools to cut through the cement mixture. There are also no special safety handling requirements with engineered wood as there are with fiber cement. Fiber cement contains silica and sprays silica dust into the air when cut. If inhaled, the dust can cause lung disease and lung cancer.
Engineered wood siding comes in 16’ length boards opposed to fiber cement and solid wood siding that come in 12’ lengths. This means that the installer can cover more ground with one board and will save time in the installation process. It is also means that there are less joints on the surface of the house which is an aesthetic concern and less cuts that need to be primed.
Pre-finished – The boards come pre-primed with the option to have them pre-painted. The home owner can choose from basically any paint color imaginable. They are not locked to a few standards colors.
Sustainable Harvest Certified – The engineered wood siding is made from sustainably harvested, fast-growing trees. It is also good to note that the entire tree is used in the process of making the strands for the boards so there is no waste, unlike solid wood siding that can only use a portion of the tree to make the boards.
Formaldehyde-Free – Formaldehyde is a binder commonly used in engineered wood products. Formaldehyde causes irritation of the skin, eyes, nose, and throat and may cause cancer, so the less formaldehyde we have in our homes, the better.
Low Maintenance and Warranties – Once painted, the siding is maintenance free for many years. If a rainscreen is installed behind the boards then the paint can last even longer. See below for more on rainscreens. Though all manufacturers are different many offer extended warranties. LP Smartside for instance offers a 5/50 year warranty and even covers hail damage if it occurs.
Aesthetics – Again, I was pleasantly surprised at the quality of the finished engineered wood siding product. The product comes in a cedar texture finish for a traditional look and a smooth finish for a more modern look. The cedar finish looks like a solid wood siding, and I think it has a better finished aesthetic quality than fiber cement.
Engineered Wood Siding Cons
All siding is only as good as its installation – Just like fiber cement, engineered wood siding needs to be primed every time a cut is made in the wood. If a cut edge is left untreated, there is the potential of water intrusion which can cause swelling and damage to the boards. This is one reason why 16′ length boards are a real benefit. The less cutting and priming required, the better.
Like most other siding materials, engineered wood siding needs to be held off the ground by 6″ or as specified by the manufacturer. Installers need to be mindful of the required gap above window heads and the vertical gap between each board to allow for expansion.
Treated Wood – There are trade offs with every product. Engineered wood siding is treated with zinc-borate. The manufacturer, LP, states that zinc-borate is a safe treatment process that is commonly used in household items such as paper, carpet and paint, but I plan to find out a bit more about zinc-borate before I feel totally comfortable putting it on our house. The trade off I mentioned is that because the wood is treated, it lasts a long time. Untreated wood must be painted and replaced more frequently which also does harm to the environment.
In my next post, I will compare engineered wood siding to other siding options to show why we are ultimately choosing this siding option.
Side Bar: Rainscreen Installation
A rainscreen is fancy term for adding an air gap between the siding and the wall sheathing on a house. Houses have a wood wall sheathing that is attached directly to the stud framing. The sheathing is usually made of 4’x8′ sheets of plywood or OSB. This provides rigidity to the house and creates a barrier between the inside and the outside of the house. After the sheathing is installed, a house wrap sheet, (Tyvek is a popular name brand) goes over the sheathing. This further protects water from getting into the walls of the house. The most common practice is to install siding directly over the Tyvek sheet. The problem with this practice is that when water gets behind the siding (which is inevitable) it is very hard for the water to run down the side of the wall to escape. This often leads to water damaging the siding and the paint on the siding to peel. Water trapped behind the siding can also lead to water intrusion into the house.
Rainscreens create a pathway for water to move down the side of the wall and exit at the bottom. Now water is not being trapped directly behind the siding. A rainscreen is usually created by installing 1×3 wood furring strips placed vertically every 16″ around the entire face of the house. The siding is then attached to the wood furring. The benefits of a rainscreen system are that siding can more easily dry out when it gets wet and paint lasts longer on the siding since it is not constantly wet.
Rainscreens do add cost to the initial installation due to the added material and labor of installing all the strapping, but the cost will pay for itself over time since the siding will last longer and there will be less maintenance with painting and replacing rotten boards.