Blog Post

TimberSIL Now Made with Waste-Ag Silicate

We first wrote about TimberSIL from TimberSIL Products in a 2004 article in EBN, touting the company's treated wood as a revolution in the treated wood industry. From an environmental standpoint, a recent enhancement makes the product even better. I've just participated in the three-day Build Well conference in Sausalito--a first-ever think-tank conference organized by Bruce King, Ann Edminster, Jan Stensland, and Tom Hahn through the Ecological Building Network. It was a wonderful conference, one of the most exciting I've attended in years. Most of the hundred or so participants were staying at the gorgeous retreat center Cavallo Point Lodge where the event was held, just across the Golden Gate Bridge from San Francisco. The informal atmosphere afforded plenty of opportunity to get to know each other and carry on in-depth conversations on the topic of the moment.

Among the participants (and presenters) was Karen Slimak of Timber Treatment Technologies. In a discussion with Slimak over dinner the first evening, I learned--almost by coincidence--that the sodium silicate the company uses in its treatment process is derived 100% from burning rice hulls. Rice hulls have a high silica content--up to about 60%--and this silica is extracted in a gasification process in which the hulls are heated to produce three products: hydrogen (which is burned to generate electricity), carbon (used in making activated carbon for filters), and amorphous sodium silicate.

Timber Treatment Technologies switched entirely to this waste agricultural source of sodium silicate about a year ago. The material is sourced from a company that processes rice hulls from Louisiana and Mississippi. According to Slimak, millions of tons of rice hulls are available--an almost unlimited supply to support her company as it expands--though the company is investigating other clean sources of the compound.

Deriving the sodium silicate from a renewable supply reduces the environmental footprint of TimberSIL. Typically, the compound is derived from processing sand in an energy-intensive and polluting process.

This new feature of TimberSIL (it should now be able to help earn the rapidly renewable materials credit in LEED) adds to an impressive list of benefits of the product. Unlike chemically treated wood (using creosote, ACA, CCA, copper azole, and others), sodium silicate is totally nontoxic and VOC-free. It has been used in laundry detergents and other consumer products for well over 100 years. Rather than making wood toxic to decay organisms, the process surrounds wood cells with an amorphous glass--rendering the wood unrecognizable as a food source. TimberSIL is also noncorrosive and, in fact, sodium silicate is used as a corrosion inhibitor in sewage treatment plants.

TimberSIL is currently produced at a plant in South Carolina and distributed nationally by American International Forest Products, of Portland, Oregon. There are plans for additional plants, both in North America and abroad. Results of new fire tests (ASTM E-84) and accelerated aging (ASTM D-2898) have been very positive, with TimberSIL easily meeting the standard for Class A fire resistance and meeting California's stringent ignition-resistance standard for decking. More details are available in our January 2009 article in EBN.

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Timber Treatment Technologies

Springfield, Virginia


www.timbersilwood.comwww.timbersilproducts.comI invite you to share your comments on this blog. Have you used TimberSIL?  

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See more on this product in the GreenSpec Guide

Published February 4, 2010

(2010, February 4). TimberSIL Now Made with Waste-Ag Silicate. Retrieved from

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November 9, 2010 - 8:40 am

In looking for a local source for shopping Timbersil lumber for repair and restoration purposes, I found that a 70 to 90 minute plus drive for a small load here and there too much. I am in coastal Southern California with constant termite and dryrot issues. Your product seems like a dream come true for me and my now small retirement business. Does California still grow enough rice to produce the hulls needed for a plant in Northern California? Seems like a logical location for a plant nearer the wood and rice hull sources. I think there "wood" be a great market for your product if you had better distribution. I am thinking in San Diego County. I will be tearing off a roof and will be doing so extensive repairs when I return from Micronesia, I will look into driving to OC for larger purchase.

September 17, 2010 - 11:09 pm

I am about to make a purchase for decking but I wish the siding were available.
It seems neither the shakes nor clapboard type siding is actually available.

February 22, 2010 - 6:16 pm

Fiber cement siding is high in silica content, which is listed on the label as a carcinogen in the state of California. I am all for green products, but as a carpenter installing them, I hate the feeling that the products I'm working with have the potential to cause serious harm to me over the course of my career.

February 23, 2010 - 2:39 am

Isaac, if you notice that most cement additives are using chrystalline silicate which is harmful and can lead to silicosis which attacks the lungs. So if you are using chrystalline silicate in a powder form you must take extreme precautions, but as Alex Wilson stated TimberSIL is using a non-chrystalline silicate (RHA). This is a harmless water solution and when the moisture is removed it is also harmless. Leaving you safe and healthy. Also, we are not talking about cement or siding, we are talking about dimensional lumber. Apples and oranges, my friend, which are both as healthy as amorphous sodium silicate. Good luck with your fiber cement siding. Co2 emissions too! Should really get a new product line! Just a thought. Jph

February 23, 2010 - 3:50 am

Joe, try looking up Dewee's Island. That project was done 3.5 or 4 years ago and the wood is holding up pretty well. For staining I recommend using DEFY from SaverSystems which is a 250 or lower VOC wood stain (Cedar, Redwood, Light Walnut, Gray) and you should use their clear Extreme Coat which is a culmination of all of their tech. Alex, you should also check out DEFY. Joe, the question really is film or non-film forming? TimberSIL needs to be sanded to create grip. There is an awful lot of silicate and this fills the gaps pretty well. So sanding creates some grip for a coating and opens up the pores of the wood a little. Thompson's doesn't work so well anyway, but Sikken's is great although a little pricy. Hope this helps buddy. Sorry for being shameless, but I sell the products and they are great pair TS & DEFY.

February 23, 2010 - 3:34 am

I would like to use on my deck in SC. But I understand from rep at Timbersil that they only recommend a water repellent. I would like to stain the deck. Before I use this product I would like to see a deck that is two or more years old. I don't seem to be able to find one anywhere. I am located in SC only a 120 miles from the plant. Surely there is a deck somewhere in the southeast using this product.

February 12, 2010 - 4:03 pm

I was involved with rebuilding a boat dock for a boating and swimming club on San Francisco Bay about 18 months ago and was searching for a low-toxic material that could withstand the marine conditions. TimberSIL seemed a great solution. At that time we would have had to have the materials shipped from South Carolina! The closest distributor is now in Southern California. I have to think there would be a market for this product in marine projects around San Francisco Bay where there is a lot of concern about toxic leaching into the water. I just wish you could get it here in SF!
Bill Burke

February 8, 2010 - 4:12 am

Yes, TimberSIL Products is still in business and focusing on some new applications. One of those is railroad ties. Concrete ties are apparently found to be failing after only 20 years, and the other option, creosote-treated wood, presents a toxicity concern for workers especially. The company last year installed a test section of track and is pursuing that market quite actively. With the building industry depressed, other markets could play a key role in allowing the company to grow. The company is still operating only one plant, as far as I know, in South Carolina.

February 6, 2010 - 8:57 pm

TimberSIL made by using acidified sodium silicate is novel. I hope it works. Are they still in business?