Installing Thermally Modified Wood Siding.

Thermally modified wood siding can be fastened using different installation methods but I suggest that you follow the manufacturers recommended installation guidelines. I recently visited a job site in Burlington, Ontario where the contractor was installing the thermally modified wood siding on a private residence and the contractors took some time to explain their installation method.

Given the right installation wood siding can last for decades or even centuries. Thermally modified wood siding is a type of exterior finish material that adds an authentic quality to any new or renovation project and is easy to install. Siding is applied in overlapping horizontal boards ranging from 4 to 12 inches in width including an overlap of ½ to 2 inches. There are many types of horizontal joints through which siding is fastened including a plain bevel, a rabbeted bevel, a V shiplap, a cove shiplap and tongue and groove. This particular installation utilized a tongue and groove profile in a 5.5″ width board.

In this installation the thermally modified wood siding was attached to furring strips attached to a layer of plywood sheathing covered with Tyvek HomeWrap which acts as a water and air barrier, but allows water vapor to pass through so as not to accumulate in the wall assembly. As a result, it can contribute to improved building durability by helping to protect homes against damaging wind and rain that can penetrate the exterior siding.

When cutting the thermally modified wood siding boards to length a quality circular saw must be used, making sure that each joint falls on a furring strip. The contractors used a measuring square to ensure that each board was cut exactly square. Otherwise, uneven gaps will appear at the joints on the finished wall. Cut slowly to guard against splintered or jagged edges. They installed the siding so that the joints would align vertically in alternating courses as best possible. The ends of any pieces of thermally modified wood siding that were cut had end sealer applied to the end of the pc. that was cut. The contractors used a product called “Ipe-Seal” which is designed to prevent end checking (drying splits) on freshly cut ends of wood exposing the end grain.

On this particular installation the thermally modified wood siding was installed from the bottom up and required scaffolding to complete. The lowest siding boards were installed about an inch below the top of the foundation wall. Siding is nailed into each wood furring strip using a 2″ 16 gauge stainless steel nail installed with a power nailer.  A quality power nailer can sink thousands of nails a day consistently and accurately with a minimum amount of maintenance. The thermally modified wood siding was nailed into each furring strip. The first piece of siding installed at the bottom was fastened through the face and through the tongue. Each piece of siding thereafter was nailed through the tongue on a 45 degree angle where the reveal meets the bottom portion of the tongue and nailed at each 16″ interval where the furring strips were located. If corner boards are not used, the siding boards of adjacent walls extend to meet in a mitered joint at the corner which was the installation method used were the corners met.

CFP Cladding & Decking thermally modified wood.

Thermal Ash siding mitered corner.

Stainless Steel nails for thermally modified wood siding

Elmer’s Pro Bond Max for gluing thermally modified wood

Thermally Modified wood siding in Nova profile made from North American Ash.

Thermally treated wood siding. Made from FSC North American Ash finished with a clear semi gloss.

Thermally modified ash siding installation