Wood Stain and Sustainability


Posted by Hermann Thoene | Posted in Log Home Finishing | Posted on 12-07-2012

Guest post by Ron Cameron from Finishes 1st:


Environmental Sustainability to the Planet”

Being capable of being continued with minimal long-term effect on the environment.

Environmental Sustainability to the Home Owner”

Being capable of being continued with minimal long-term effect on the home owners pocket book.

So we have two areas to focus on: the environment and people. We need to be able to accommodate both to succeed.

How do we measure sustainability?

The Canadian gov’t measures VOCs (Volatile Organic Compounds) in products to determine the effect they have on the environment (which includes the atmosphere, people and vegetation). VOCs are vapours or gases emitted by various solids or liquids, many of which have short and long term adverse health effects.

What % of the total pollutants emitted into the atmosphere are singled out to be Solvent use (paint or stain) VOCs?

The gov’t’s website shows that in a recent study 28% of the total emitted pollutants came from Solvent use. The gov’t also says that it will have, by the spring of 2010, a new standard which will reduce the VOCs levels to 250 grams per litre. Currently (in 2009) there is no ceiling in this area.

How many types of stain are there?

There are 3 generally accepted types:

  • Waterborne
  • Water base
  • Solvent base

What are the VOC levels of each stain type?

  • There are 2 varieties of Waterborne stains:
    • Old generation – 250 grams per litre
    • New ‘Nano’ generation – <less than 100 grams per litre
  • Water Base – 270 grams per litre
  • Solvent Base – 350 to over 800 grams per litre

What are the differences between the 3 different types of stain?

  1. Solvent base uses mineral spirits (another name for solvents) to mix with the stain so it can be applied, and it needs to be cleaned up with more “mineral spirits.” Both Water base and Solvent base are what is called “film forming”, meaning they build in layers. They are both based on the belief that covering the wood is the best way to protect it, but Solvent base produces a harder coat than Water base, and with regular maintenance will last 20 to 25 years. This is where the gov’t’s new legislation comes in! After the spring of 2010 this product in its current form will be classified as a hazardous chemical, and thus Solvent base products will not be available for maintenance, reducing the life of the stain to between 7 to 10 years.
  1. Water base, like Waterborne, uses water as a thinner to mix with the resin so that it can be applied, and cleans up with soap and water. This, though, is where the similarities end. Water base is designed to sit on the surface of the wood, the rationale being that, if the surface is coated, fungus and mildew cannot get into the wood. This would be true, except for one thing – wood expands and contracts with the seasons and this continuous stress to the stain breaks it down sooner. Water base stains have shown to have a life span of 17 to 20 years if regular maintenance is done.
  1. Waterborne, as well as being the most environmentally friendly of the 3, gets into the surface of the wood, and is known as a breathable stain. This means that humidity can pass through it and the wood can expand and contract with the elements normally. It also has mild fungicides and mildecides to stop airborne fungus and mildew from entering the wood and grow unchecked. Waterborne uses water as a thinner to mix with the resin so that it can be applied, and cleans up with soap and water. Being able to get into the wood allows the stain to expand and contract so that it doesn’t crack or peel, giving it an expected life of 3 or more decades if regularly maintained.

How come the stains on some homes last longer than others, even when they have been maintained?

The stain itself represents only about 25% of the equation, the other 75% is in the preparation of the wood. Other factors that affect the life of the stain are cracks (or checks), roof size (overhang) and methods of application (sprayed on versus brushed on etc.).

A major example of the importance of the preparation of wood that affects stain performance has more to do with fungus and mildew, especially in humid areas such as the Lower Mainland. It is almost guaranteed that there will be mildew and fungus present in logs even if you can’t see them. They lay dormant until the right conditions happen and then reproduce at a high rate. It is always best to do a mildew cleanse with logs, because if the mildew does show up the only solution is to strip the stain off the house and start again. Not only is this expensive, but it multiplies the amount of VOCs emitted into the atmosphere (and the applicator’s lungs) each time the stain has to be stripped and reapplied. The solution is the use of an eco-friendly product that kills the existing mildew and fungus, regardless of which stain is applied.

While there are many factors that influence the longevity of stain, most of them can easily be dealt with if the architect, builder, general contractor and home owner all know and do their part. The architect needs to know that even though allowing beams and trusses to extend beyond the roof line looks attractive, they will require much more maintenance, and even then will fail before the rest of the house. The builder needs to protect the wood during the build process to eliminate fungus, mildew and sun damage so that the general contractor will not have to spend more money and chemicals to fix the wood during the assembly phase. Lastly, the home owner must understand that they have a responsibility to maintain the stain on a regular basis (usually 3 to 5 years for transparent stain, 4 to 6 for semi-transparent and 6 to 10+ for semi-solid stain).

Maintenance varies for the different types of stain, ranging from a cleaning, light sanding, and stain application for water base and solvent base (sometimes a primer is required for solvent base as well), to a cleaning and an application only of clear stain for waterborne.

Can’t wood be pre-finished at the factory or at a pre-finisher to eliminate most of these problems from occurring?

Yes, and for siding, board & batten, fascia and, in fact, for any wood up to 3” thick and 24” wide this is undoubtedly the best method (logs, of course, cannot be pre-finished). The difficulty is that the general contractor would lose out on the labour and usually convinces the home owner that it would be a waste of good money and would be more expensive. The result is a surface that is compromised by being out in the weather too long, so that the stain cannot bond to the surface as well.

To summarize:

Conditions are going to change as far as the government’s allowable levels of VOCs are concerned. When this happens, those products we currently know as solvent base stains will disappear. Will the manufacturers of solvent base stains come up with something new to meet the new levels? Undoubtedly, but the question is whether it will be compatible with their old stain. If not, the home owner will face more cost pre-maturely and the environment will be adversely affected as well.

The real solution is to do it right in the first place, and not to cut corners. It is a certainty that the adage “you can pay a little now, or you can pay a lot more later” applies here.

Finishes 1st is an independent supplier of products, and, as such, we are not limited by the marketing department of a particular manufacturer. We have done a lot of homework in choosing our line up. Our stain of choice is a new generation waterborne stain. It has the lowest VOCs, permeates into the wood, kills airborne mildew and fungus on contact and lasts the longest. Because it is waterborne it breathes, and this has an added advantage of being able to be applied with moisture contents in wood as high as 25% (freshly cut trees). To compare, the other types of stain need the wood to be in the 16 to 18% range (air dried) before they can be applied. This can take up to 3 to 4 months of drying time before the first coat of Water and Solvent base stains can be applied and up to a year for the completion of the stain process. During this wait time, mold and mildew damage, as well as sun damage, is likely to occur.

Incidentally, when it comes to siding, shakes, board & batten and fascia, etc., mildew and fungus are less of an issue because they usually don’t go deeper than the first 3 rings of a log, and these types of cut wood are cut from deeper in the log. If the wood is pre-stained, there is little chance mold & mildew will get into the wood, and the wood will be well protected while on site waiting to go on the home. On the other hand, if the staining it is to be done on site, mildew and fungus can, and will, get into the wood and the extra step of mildew cleansing will be necessary. The cleaner I prefer is an environmentally friendly, easy to apply type, but even so, it does have some VOCs, a point to consider when it comes to protecting the environment.

In conclusion, Finishes 1st has over 12 years’ of experience in the stain industry, specializing in environmentally favourable products as much as possible. We have learned a lot about protecting the environment and the home owner, and we will continue to learn as this is a never ending process. Our goal is to share our knowledge with anyone involved in the building of a home, because both the environment and the home owner have a lot to lose if the work is not done correctly the first time. In short, both have a vested interest in sustainability, each from a slightly different view.

For more information on this and other things, look at my website www.finishes1st.com send me an email at F1st@telus.net, I’d love to help.

Ron Cameron