Thermory Pine and Clear Pine
Pinus Sylvestris & Pinus Radiata
We have partnered with Thermory and their line of thermally modified woods, because of their outstanding quality control and generational expertise that is next to none throughout the thermal modification process. Thermally modified Pine is a great example of where we take an interior-use-only wood, and through modification, turn it into a top notch exterior wood. We stock Thermo-Pine in two varieties: an STK (select tight knot) grade and a clear grade. To pull this grade difference off, we actually use two different pine species: a European or Scots Pine for the knotty and a totally clear Radiata Pine (AKA Monterey Pine), which is an FSC, plantation grown species.
Like all thermally modified woods, the working properties are nearly identical – just without the seasonal movement. Thermally modified Pine can still be milled and joined, and glued, nailed/screwed and finished like unmodified Pine. The biggest difference is the color. Instead of the white wood look of Pine, you now have a warm caramel color. It will still fade to a silvery gray if desired, or it can be finished and maintained annually to retain the natural color.
Thermally modified Pine technical properties
With a uniformly low moisture content and the sugars & other extractives removed, thermally modified woods will be thirsty. They take finish very well, but you may find that you need more finish than other woods in order to get the same results. Likewise, gluing thermally modified woods requires no special glues; however, the curing time of water based glues on thermally modified woods will be faster as more moisture is absorbed by the thirsty thermo-wood. Note that, due to hardening of the cell walls during extremely high temperatures above 419 F, this uptake of water does not cause the wood fibers to swell, making the board expand like unmodified woods.
Thermally modified Pine won’t cup or twist as the movement is now measured around 0.1% in both the tangential and radial directions. This is important, because that difference in movement or T/R ratio is what causes boards to warp. Now any movement you see with a thermo-wood species will be uniform and minimal.
With cell wall hardening, the wood itself becomes marginally harder but not dramatically so. Your Janka hardness numbers will be very much the same as unmodified Scots and Radiata Pines (540 and 720-ish respectively). The hardening of the cell walls does reduce some of the stiffness (MOE) numbers, and it is common to see around a 20% reduction in these numbers as the wood is a bit more brittle. Bending Strength (MOR) will see a reduction as well but only about -1% over unmodified. TO BE CLEAR, these reductions have no effect on the workability or longevity of the wood when used as cladding and decking with proper joist spacing. So maybe we won’t build a bridge out of thermally modified woods, but that isn’t the application these woods are meant for.
Finally, with most of the water and sugars removed, there will be about a 20% reduction in overall weight of thermally modified Pine. As a cladding material, this is a great benefit. Just ask anyone who has installed a 12′ length of tongue & grooved cladding board while standing on a ladder 15 feet off the ground. The weight reduction lowers the density of the material as well, which is attributed to the thirsty nature mentioned above, but it also makes the workability very nice. Like similar lower density woods, you will find that they cut nicely.
Pinus Radiata
Pinus sylvestris
Learn More about Thermally Modified Woods
It’s a complex subject, and while not a new technology, the market is full of options and new products every day. In the case of Thermo-Pine, it allow us to use a non exterior wood for exterior applications.
Thermory Benchmark Pine can be used for decking or cladding, and it can be made in a number of profiles for your specific application. Thermo-Pine is rated as Class 2 for 15+ years resistance against decay, so you can trust it for all of your exterior projects. It is available end matched with Thermory’s JEM joint for a seamless and strong connection that does not have to be over a joist. More importantly, this means less waste on the install without having to use longer lengths or trimming based on joist spacing. For more information on JEM joint strength, download the strength test report from Thermory
Thermory Pine Sizes and Grades
There are really 2 separate products that would roll up under thermally modified Pine. The biggest distinction between the two is that one has knots and the other is clear. Dimensions are specific to the application, and a variety of profiles are available for cladding and decking. We can provide custom milling using any of our thousands of profiles as well as give you a custom finish option to suit your project.
With sizing, we can provide traditional 1×4 and 1×6 decking boards along with thicker sizes like 5/4×4 and 5/4×6. Cladding boards are available in 1x thickness with widths in 4, 5, 6, & 8″. Also in 1x material, we can provide additional trim and fascia in 1×4, 5, 6, and 8″ width. In thicker 2x material, we have 2×4 and 2×6.
**Board lengths for Pine are available from 9 – 19.6 ft (1200-4800) mm**
Why Thermory? After searching for the right brand to partner with in the modified wood space, we feel Thermory has the right amount of generational knowledge and expertise to complement our history and high regard for the finest quality products and robust, ethical sourcing practices
