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TimberSIL® – A Great Idea?

Great Ideas May Not Always Bring Great Results

Much ado has been made about alternatives to CCA (Chromated Copper Arsenate) pressure preservative treated lumber. CCA has been used to pressure treat lumber since the 1940s. Since the 1970s, the majority of the wood used in outdoor residential settings (as well as pole buildings) has been CCA-treated wood. Effective December 31, 2003, no wood treater or manufacturer may treat wood with CCA for residential uses, with certain exceptions.

Treated Wood Stamp This resulted in a plethora of alternative pressure preservative treatment chemicals being introduced which, on the surface, sound like a veritable alphabet soup – ACQ, CA-B, CA-C, MCA, etc.

Although not used for preservation of timbers for structural in ground use, there have been some interesting alternatives, not all of which have necessarily worked in all cases.

Brad Pitt’s Make It Right Foundation has built 100 energy-efficient and eco-friendly houses in New Orleans to replace homes damaged by Hurricane Katrina. Unfortunately, the organization believes that some of the wood it used is now rotting, reports The New Orleans Advocate.

The organization used TimberSIL®, an innovative glass-infused wood product produced by a South Carolina manufacturer, to build porches and outside steps. The absence of chromated copper arsenate and other chemicals typically used to prevent rot and decay was a selling point for Make It Right.

“Instead of treating the wood with toxic chemicals, it’s actually infused with sand, or silica, such that it takes on the properties of treated lumber,” Tom Darden, the executive director of Make It Right, said in a 2010 interview. “At the end of its life cycle, which is estimated to be about 300 years, it can be mulched and composted, believe it or not.”

Unfortunately, Make It Right has found TimberSIL® can’t stand the moisture in the balmy city and has turned dark gray and begun falling apart. The organization has replaced wood in 30 homes and is considering legal action. TimberSIL® has reportedly caused trouble for at least one other client: a project in Western Massachusetts which had to be repaired when the builders found the wood retained too much moisture and couldn’t hold paint.

With more and more pole buildings being used for residential purposes, with alternative sidings to the traditional steel, as well as attached decks, it would behoove some serious research and consideration (in this author’s humble opinion) before utilization of this particular product

This entry was posted in Lumber and tagged lumber preservative, treated lumber, pressure treated lumber on February 19, 2014 by admin.

MCA: Micronized Copper Technology

Particulate (micronized or dispersed) copper preservative technology has recently been introduced in the USA and Europe. In these systems, the copper is ground to micro sized particles and suspended in water rather than being dissolved in a chemical reaction as is the case with other copper products such as ACQ and Copper Azole. There are currently two particulate copper systems in production. One system uses a quat biocide system (known as MCQ) and is a take-off of ACQ. The other uses an azole biocide (known as MCA or μCA-C) and is a take-off of Copper Azole.

Proponents of the particulate copper systems make the case the particulate copper system perform as well or better than the dissolved copper systems as a wood preservative, but other industry researchers disagree. None of the particulate copper systems have been submitted to the American Wood Protection Association (AWPA) for evaluation, thus the particulate systems should not be used in applications where AWPA standards are required. However, all of the particulate copper systems have been tested and approved for building code requirements by the International Code Council (ICC). The particulate copper systems provide a lighter color than dissolved copper systems such as ACQ or copper azole.

Proponents of the micronized copper systems claim the systems are subject to third party inspection under a quality monitor program. However, the monitoring program is not subject to oversight by the American Lumber Standards Committee (ALSC) as is required for the AWPA standard systems.

Two particulate copper systems, one marketed by Osmose as MicroPro and the other as Wolmanized using μCA-C formulation, have achieved Environmentally Preferable Product (EPP) certification. The EPP certification was issued by Scientific Certifications Systems (SCS), and is based on a comparative life-cycle impact assessments with an industry standard.

The copper particle size used in the “micronized” copper products ranges from 1 to 700 nm with an average under 300 nm. Larger particles (such as actual micron-scale particles) of copper do not adequately penetrate the wood cell walls. These micronized preservatives use nano particles of copper oxide, for which there are alleged safety concerns.

A competitor of Osmose, Viance, has waged what Osmose terms as a “negative public relations campaign questioning the effect”.

Osmose President Paul A. Goydan calls the campaign, “desperate, deceptive and damaging to the entire treated wood industry, including preservative manufacturers, wood treatment companies, distributors, retailers, contractors and deck builders.”

The chemical retention level of Micronized Copper is 0.23 lb/ft³ in order to meet the IBC (International Building Code) requirement of a UC-4B for structural in ground use in post frame buildings.

East of the Rocky Mountains, MCA has become the pressure treatment of choice for one of the large “box stores” as it requires no special fasteners (unlike ACQ treatments). ACQ treatments have been found to more quickly erode fasteners in contact with the treated lumber than the former CCA, and now….MCA.

Based upon the evidence at hand…although there is not a ten year or more history of MCA use, Osmose has obtained approval by the Building Codes for their product, and I’d not think one of the largest Big Box stores in America would endorse it’s use without close scrutiny. At this point, I would have no reservations using MCA treated lumber in any building of my own.

This entry was posted in Lumber and tagged CCA, lumber preservative, treated lumber, ACQ on August 23, 2013 by admin.

Pressure Treating Glulam Columns

We recently had one of our engineers specify the use of glulam pressure treated columns to support one of our custom designed pole buildings. The client was concerned about pressure treated glulams in the ground, so it was time for some heavy duty research.

According to the American Institute of Timber Construction (AITC), structural glued laminated timbers (glulams) can be treated with waterborne preservatives after laminating.

While in general, the laminated timber industry recommends against using waterborne preservative chemicals to pressure treat structural glued laminated timbers after bonding, this recommendation is only intended to prevent appearance problems caused by treatment and subsequent re-drying. Pressure treatment with waterborne chemicals after bonding does not generally make the laminated timber structurally unfit. Treating structural glued laminated timbers (glulams) with waterborne chemicals after bonding may be a viable option for applications where appearance is less critical, like for pole buildings.

Adhesives used in modern glulams are extremely durable and are considered waterproof. Glulam timbers treated after bonding will accept treatment and resist decay similar to treated sawn timbers of the same species and will perform similarly in service. If the appearance of this product is acceptable to the consumer, it can be used successfully in applications where treated wood is required. Provided the structural requirements of the application are met (meaning – was the right size and grade of pole selected for factors such as wind speed, snow load, etc.), treated glulam timbers can be used in place of treated sawn timbers.

Pressure-treatment is a process of applying preservative chemicals to wood to increase resistance to decay. Pressure-treated wood is used in applications where wood will be wet and subject to decay.

Pressure treatment of properly manufactured structural glued laminated timber members will not cause delamination. Delamination refers to adhesive failure leading to separation of bond lines. Adhesives used in modern glulam products must meet stringent standards for moisture resistance and durability. Additionally, adhesive bonds in glulams must also pass rigorous daily testing for strength and durability. Consequently, delamination is very rare in structural glued laminated timber whether it is pressure-treated after bonding or not. Checks can occur along bond lines due to stress concentrations between laminations and are often mistaken for delamination. The presence of wood fiber separations or torn wood fibers at the bond line is the key distinguishing characteristic of checks .

If glued laminated timbers are treated after bonding, dimensional changes caused by saturation of the wood with the water-borne preservatives and their carrier followed by subsequent re-drying may result in raised grain and warping, checking, or splitting.

Some species do not accept treatment well and require incising while others can be treated successfully without incising. Southern Pine is generally not incised, while Douglas fir typically requires incising for adequate penetration of the preservative.

Bottom line is, can you use glu-lams in the ground for pole buildings if they are pressure treated for in-ground use? Absolutely! The treatment process to get them to the PT level may cause them to look not quite as pretty as the varnished beams in your cathedral ceiling, but they will be every bit as strong. And rest assured…they will not rot. If you don’t believe me – maybe you will believe the American Institute of Timber Construction.