United States and Canada

High Temperature Modified Wood Products


Termite Resistance

The termite resistance of Thermo Treated Wood is improved significantly. We remove the poly-sugars and moisture in the wood during the thermo-treatment process, termites will attack first original wood and only then Thermo Treated Wood in their quest for a strong food base.

Boards orientation - orient all deck or siding boards for application to what is commonly referred to as “bark-side up”. The growth rings curve should be pointing downward. Improper orientation will not be covered by the warranty.

Adhesive Fixing

Since the wood is entirely dried out, and has the ability to resist the water, cases of insufficient adhesive strength may arise. It is important to carefully check if the required adhesive stability can be achieved when using water-based glues.

  • It is recommended not to use water-based glues such as PVA. 
  • It may be required longer compression and drying time when applied to softwoods. Due to brittleness of thermo-treated wood high compression pressures should be avoided. 
  • Chemically hardening glues (such as polyurethane, glue based on polyvinyl acetate + hardener, resorcinol phenol and melamine resin) can be used with thermotreated wood in the same way as with non-treated wood. As levels of expansion and contraction in thermo-treated wood are 50% lower than ordinary wood, it cannot simply be attached to untreated wood. In these cases, careful preparation of both the thermo-treated and untreated wood is necessary. If raw plugs are to be used, then these should also be thermo-treated.
  • Alternatively, plastic raw plugs could be used. Up to now, no guaranteed results have been obtained on the performance of thermo-treated wood when adhesives are applied for external use. It is recommended not to use glue for external use.

When gluing thermo-treated wood, the glue manufacturer’s specific Instructions must always be referred to.

Implementation of wood deck tiles and siding

For deck surface nailing 16D common is the maximum nail size allowed and a 10D common is the minimum. Spiral-shank nails may provide additional holding power. Nails must be exterior-grade (e.g., stainless steel or hot-dipped galvanized). Use hammers gently due to the increased brittleness of TTW products.

Fastening and nailing

Standard exterior grade coarse-thread screws work well with TTW. Keep in mind the following tips:

  • Pre-drill holes to avoid splitting at edges.
  • Fasteners should be applied a minimum of 5/8" from board edge and a minimum of 1" from the board ends.
  • Face-fastening with screws provides the optimum holding conditions; however, hidden fastening systems can be used. Hidden systems that screw into the deck board and joist edges work well.
  • For Claw Fasteners we recommend to use special knocking assembly not to damage the deck during fastening process.

Use standard residential deck code to determine on-center space for decks and stair treads. Deck boards shall extend across a minimum of three joist bays and terminating board ends shall lie on joist centers. A 1/4" gap between adjacent deck boards is recommended as TTW will install dry (~4% MC) so minimal shrinkage will present. All installations should follow all local municipality code regulations.

Cutting and Drilling

Give special attention to saw and tool coarseness/fineness to better improve the end results. Saw speed will have an effect on the cut quality; generally, the higher the saw power, the better the cut quality. Radial and Table Chop saws – Use blades (10") with greater than 30-tooth carbide tipped for optimal results. Circular saws – For 7-1/4" circular saws, use a 36–40 tooth carbide tipped blade for optimal results – fewer teeth will result in a coarse cut, especially at board ends. Also, as with most wood products, be sure to use sharpened blades to ensure clean cuts. Hand saws – Standard wood handsaws also work well with TTW. Pay careful attention to the saw tooth count and blade type for optimal cutting performance. Fine tooth crosscut saws work best. Drill Bits – Use standard wood-working bits; however, extra attention should be taken when drilling near edges to avoid wood splitting. Using sharp bits and attention to tool pressure will help improve end results. Coarse, flathead borer bits will tear and split the wood; we recommend standard, round drill bits.

Ground Contact

Direct ground contact is not recommend for TTW. However, the usage of highest temperature treated material (darkest color) in ground contact, where structural performance is not critical and periodic drying of the surfaces is allowed, does not cause any significant deterioration to the material. This is especially apparent when the ground has good drainage and is made up of sand. Also, due to bacteria in the air or dirt carried in the rain, when TTW positioned near the ground, fungi can grow on the surface, as they grow on any surface (even on stone). However, this is on the surface only and can be removed by wiping or scraping. We recommend keeping thermo-treated products at least 12-18" above grade.