cedar siding install guide

Top Five Questions An Architect Should Ask About Wood Siding, But Often Do Not

1. Do I understand how to maximize the wood’s lifespan at the design stage?

The answer to this is ‘Did you watch my webinar’? Ha ha! Watch Chris’s webinar!

The design stage is the point at which you consider the south facing wall and you avoid putting giant wood expanses on this wall.  You would want to put trim, décor, accents and patio doors on this wall. The proper orientation of the home with regard to wood siding adds to the longevity of the siding.

The correct drainage plan, both outside and behind the wall, adds to the lifespan of the siding. At the design stage, if you plan for firring strips and an air space behind the siding it’s going to last longer. On the outside, if all of your trim and outdoor fixtures are designed to have the drainage of water go out and over the siding and not down onto the siding in a continuous stream, this will avoid unnecessary challenges to the stain.

At the design stage you want to plan to avoid splash-back; the water hitting the ground and bouncing back up on the siding causing blackening areas, stain failures and mold and mildew. We like to see our siding eighteen inches off the ground with some sort of a stone on the bottom.

These decisions you make at the initial design stage can literally mean double the lifespan of the wood and less hassle for your client.

2. Do I clearly understand sustainable forestry’s effect on wood siding performance and appearance?

This is an important question. I had an architect purchase redwood siding for his own home. What he got was siding from much younger trees than he expected and it caused a variation in the appearance. A great enough variation in the appearance that he rejected the order.

Consequently, a builder lost his business and Buffalo Lumber had to come up with thousands of dollars to get him what he expected. Currently, meeting those expectations is not even possible with redwood. You want to understand what to expect before you make a purchase.

Sustainable forestry has included the use of younger trees, which means your wood will change sizes to a greater degree after it’s installed. It expands more with moisture and humidity and shrinks with dry conditions. You want to make sure it’s acclimated properly and has had most of the size change it is going to go through in its life done before you actually install it.

The other effect sustainable forestry has had on wood is the substantial change in growth rings. Growth rings are what give the wood its durability, its structure and its ability to resist rot and decay. In an old-growth tree…two thousand or five thousand years old…the grain rings are so close together you could not fit a razor blade in between the rings. That wood will perform well for siding longer than any of us will be alive.

However, the younger trees that they are using now, due to sustainable forestry, have growth rings that could be up to one inch apart. They are cutting the trees at fifty, sixty and seventy years now and those rings are well apart from each other. The stability of the product is lessened. And the amount of pulp between the grain rings is what draws and expels water causing the size changes.

It is very important to understand how it’s going to look and how it’s going to perform before you specify it and put your client in an unfavorable position.

3. Does my client have a realistic maintenance plan and budgeting?

For a natural wood look, if you want it to stay the brown and amber colors of natural wood, this is going to require re-staining every few years. Many times, the owner does not realize how much maintenance is involved in keeping it looking good.

As a general rule, every year you want to inspect it and wash it. You want to address anything that turns dark or black or discolors in any way. For a smooth-face application you’re going to want to plan to re-stain it every other year; possibly every third year. You want to budget both time and money for this. If you want less maintenance than that, a rough texture face doubles the life span of any stain because it takes twice as much stain into the board.

All of these factors can catch customers by surprise. They don’t realize how often maintenance is required for wood siding. They are unfamiliar with the stain differences now versus back-in-the-day. And they weren’t prepared for how much it actually costs to clean and prepare this wood for refinishing.  A happy homeowner is one that is both knowledgeable of and agreeable to a realistic maintenance plan.

4. What effect did the 2012 VOC restrictions passed by the EPA have on semi-transparent stain performance and appearance?

In 2012 the EPA passed a law that limited the number of VOC’s that you could put in a stain. A VOC is a volatile organic compound. The EPA did not standardize this restriction. They let it be up to each state as to the level of VOC restrictions. California set it at 150 VOC’s. To make a comparison, the old stains that we love that penetrated and that have been working forever were 550 VOC’s. This has to do with the amount of solvent that goes into the stain so that it can penetrate deeply into the wood.

In 2012, because the states did not have a uniform standard, most of the manufacturers of stain, especially the big boys, had no way to create a product that was going to be of similar quality and meet all of the different regulations for the different states.  So, what they did instead was quite simply add water to the formulations until the VOC limit was reached. Because oil and water don’t mix, when you have a semi-transparent water-born, film-forming finish what you basically have is a super thin paint. It will not penetrate at all; it forms a film around the wood.

Now, it’s a thin paint so it doesn’t have any of the protections paint has, like the thickness and the opacity; so it’s prone to peeling, chipping and cracking and more problems of this nature. Water-born, film-forming finishes need to be removed from the wood on a molecular level when it comes to refinishing. The film stays on the top of the wood and you can’t stain over the film because it will peel off. So, you absolutely have to use wood strippers which are hazardous chemicals.

This doubles the prep time to really clean the wood. If it doesn’t come off completely, you’ll have to re-sand it. It’s a two week preparation process. On top of that, the chemicals in wood strippers are hugely dangerous to vegetation, pets and humans. And very offensive to certain discerning customers.

I had a customer use a stain that was film-forming. It was a great performing stain; it lasted four years on his siding. When he called us to find out what type of stain it was and what the procedure for refinishing was, we all discovered at the same time that he had to remove all of it on a molecular level and he had to use wood strippers. He did not want those chemicals on his vegetation, threatening his pets, his family, and his immediate environment. So, he actually went to the greater expense of cleaning all of the previous stain off the wood, sanding it down and then switching to an oil-based, penetrating stain.

An oil-based penetrating stain, which is more difficult to find these days, will penetrate into the wood and condition the cells inside the board. This keeps the wood from warping, cupping, and twisting. Literally, conditioning the cell structure and bonding to the cell structure as it passes through the wood. You’ve got less risk of splitting and better performance. It absorbs with very little left on the surface.

The preparation and clean up for a true oil-based stain is simple. You get oxygen bleach, which is not dangerous to vegetation or animals, water, a bucket and scrub brush. You wash your house like you’d wash a car…scrub it then rinse it off. Once it dries you are ready to refinish. Some people choose to use a wood conditioner, oxalic acid, at this point.

The big difference is that a true oil-based penetrating stain takes two days to do a refinish and a film-forming takes two weeks and requires hazardous chemical management. The problem with the VOC restrictions is that creating a true oil-based penetrating stain is very difficult. The Industry is making progress on some of the hybrids, like the alkyd emulsions.

This should be the five thousand dollar question for you, the architect, before you specify a stain, call the tech department of that stain company and ask them if the stain you’re thinking of using penetrates enough that you don’t have to remove it with wood strippers when it’s time to refinish. Because if it doesn’t you just bought yourself a ton of extra work, a ton of extra cost, a ton of extra noxious chemicals and a real, good old-fashioned pain in the butt.

5. Should I specify redwood or cedar for exterior siding?

Now, this is an important question because so many architects throughout my many years in the wood business have specified redwood based on the reputation it gained years ago.

Back when the Industry was clear cutting all of the old growth redwood trees and the siding that was made from those two thousand-plus year old trees was the greatest performing exterior wood ever, on the planet. Then, redwood became our lesson on sustainable forestry. We milled it from the late 1800’s through the 1960’s, basically cutting every single redwood until it was an endangered species.

Today we are using second and third growth redwood with weaker performance factors. So, unless you like the rarity and the fact that it won’t be around very long, redwood is not nearly as good a performer as cedar.

Cedar is still available in larger forests. You’re getting wood from an older tree. You’re getting a tighter grain ring. And cedar in the high grades, vertical grains, will actually perform the way it’s supposed to. You’re spending your money for rot resistance and decay resistance and performance.

So, to answer the question, always specify cedar unless there is a personal or extenuating reason to use redwood. Take a look at my information on the redwood pages before you specify anything. I created that redwood explanation because of the architect I wrote about earlier, who hated the appearance of the redwood he bought because of the difference between young and old and refused it because it was for his own home. He was angry, the builder lost his job, we lost a good customer, the lumber yards were mad…mass hysteria!

Be sure of the performance and appearance differences of redwood in the new growth trees today before you specify it.  Cedar is your best bet.

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