BORATE

Borate-Treated Wood: Safe, Effective Protection Against Decay & Termites

• Laboratory tests have shown that the treatment has no significant effect on the strength of wood. 

• Present indications with roof trusses are that metal plate fasteners can be used with the treated wood without any significant problems arising. 

• Wood that has been pressure treated with borate is only slightly more abrasive than untreated wood. 

• SillBor® borate pressure treated wood is suitable for most purposes in building construction work. 

Ideal Uses for Sillbor® in Residential, Industrial, & Agricultural Projects

• Roof battens, purlins, trusses, wall plates, ceiling joists, floor beams and boarding, internal structural members and door frames, as well as painted external joinery are all examples where the treated wood could be used quite satisfactorily.

• External joinery made from pressure treated wood should be primed before leaving the workshop and, once on site, positioned and painted as soon as possible.

• Where borate-treated wood is used for purposes such as cladding or external woodwork.

Safe Use & Handling Guidelines for Sillbor® Treated Lumber

USE OF PRESSURE-TREATED WOOD. SillBor® borate pressure treated wood is suitable for most purposes in building construction work. Roof battens, purlins, trusses, wall plates, ceiling joists, floor beams and boarding, internal structural members and door frames, as well as painted external joinery are all examples where the treated wood could be used quire satisfactorily. 

 

Wood that has been pressure treated with borate is only slightly more abrasive than untreated wood. Present indications with roof trusses are that metal plant fasteners can be used with the treated wood without any significant problems arising. 

 

Laboratory tests have shown that the treatment has no significant effect on the strength of wood. Present indications with roof trusses are that metal plate fasteners can be used with the treated wood without any significant problems arising. Provided that the SillBor® treated wood is dried to a surface moisture content of 18% or below, there should be no adverse effect on painting. Oil based, alkyd based, and emulsion (acrylic) primers have been used without any difficulties being recorded. If for any reason the wood becomes wetted under the paint film, adhesion may be impaired. 

 

If it is properly dried to the appropriate moisture content and all surface deposits removed, SillBor® borate-treated wood can be glued successfully with most normally assembly glues. Although there is some conflicting experimental evidence of the compatibility of borate-treated wood with glues of the phenol or resorcinol type, there is little evidence of failure in practice.

Sillbor® Treatment Compliance with AWPA & Building Code Standards

Borate-treated wood is referenced in the following 2003 model codes.

• International Building Code:section 2308.1.8, preservative treated wood

• International Residential Code:section R319.1, protection against decay

• International Residential Code:section R320, protection against termites

Best Management Practices for Sillbor® Treated Lumber

The Western Wood Preservers Institute, in conjunction with industry representatives, users, and scientists, developed BMPs to help ensure fixation of preservative chemical in treated wood prior to shipment. In the fixation process, some preservative components bond to the wood while others form insoluble precipitates. Specification of BMPs results in wood with a very high percentage of fixed preservative and may also reduce shipping weight. 

Enhanced Preservative Penetration in Borate Tretments Through Incising

In many western species, penetration improvement methods are employed to improve the depth and uniformity of preservative penetration into wood. Most commonly this is seen as a pattern of slits ("incisions") on the surface of lumber. Full-length incising and deep-incising are other methods, as are radial-drilling and through-boring, used mostly for poles and piling.

Although these methods can improve preservation, they can result in a strength reduction for the wood, depending on the pattern, size, and number of incisions. When treated sawn wood products have been incised, the reference design values must be multiplied by the incising factor, Ci, in accordance with section 4.3.8 of the National Design Specification for Wood Construction. A review of penetration improvement methods is recommended before insertion into a specification.

NOTE: Incising is required by the AWPA Standards for refractory species. DF is a refractory species with up to 75 % heartwood.

Why 'Treated to Refusal' Matters for Sillbor® Treated Wood Performance

This phrase — Treated to Refusal — indicates that the wood was treated under specific conditions until it refused additional preservative, a point usually below the requirements of industry standards. The result is wood that cannot be relied upon to last as long as wood that meets standards. Such wood does not comply with model building code requirements for treated wood. 

To assure yourself of properly treated wood, look for the logo of an ALSC-accredited inspection agency on lumber tags or ink stamps. The logo often appears beside a Checkmark symbol.

Hardware for Borate- Treated Wood Applications 

Wood treated with DOT-type borate, such as SillBor®, has been shown to have corrosion levels comparable to traditional CCA-treated wood. Standard, code-compliant hardware is suitable for use. While galvanized fasteners and connectors are recommended, non-galvanized hardware that meets model code specifications is also acceptable for attaching joists, studs, or other framing to SillBor®, as long as the wood remains dry and protected from moisture and weather exposure. Similarly, standard galvanized strapping or mild steel anchor bolts (½" diameter or larger) may be used to fasten SillBor® to foundations under dry-service conditions. 

Sillbor® Treatment Effectiveness Across Douglas Fir& Multiple Wood Specs

According to AWPA guidelines, borate treatments are approved for use on a variety of wood products. 

• Pressure-treated borates can be applied to lumber without incising in species such as southern pine, hem-fir, jack pine, spruce, pine, fir, ponderosa pine, lodgepole pine, red pine, and eastern white pine.

• For denser species like coastal Douglas fir and western SPF, incising is required to ensure adequate preservative penetration.

• Borates are also suitable for treating plywood made from southern pine and Douglas fir. Additionally, they can be integrated into the resin binders during the manufacturing of oriented strand board (OSB) for use in wall sheathing, roof panels, radiant barrier panels, and subflooring.