ThermalBrown Shiplap Lumber

Specification Sheet #7230 - ThermalBrown Lumber


Mixed Species. May include Pines, Firs, Spruce, Larch, Oak, Elm, Hickory, Hemlock, Ash, Maple, Beech, Poplar, Cedar, and/or other species. Generally heavy to (or even exclusively) softwoods unless hardwoods are specifically ordered. Trestlewood can include hardwoods at its discretion. Mixed Species means that any combination of species (including all one species) is allowed.


ThermalBrown Lumber is lumber which is run through a thermal modification process. Lumber used in Trestlewood's ThermalBrown Lumber program can be i) lumber reclaimed from various salvage projects, ii) lumber cut from beetle-killed, fire-killed or dead-standing trees, iii) lumber cut from material which has weathered out of spec, and/or iv) new lumber. Lumber which is antique/reclaimed will generally be labeled as such.


Nails and fasteners are generally removed (if they existed in the first place.) ThermalBrown Lumber which comes from new lumber will often not have nail or other fastener holes.


Unlimited knots; some tight, some loose or fallen out


Unlimited as long as board is sound

Grain Pattern


Moisture Content/Stability

Thermally modified to a low moisture content. Thermally modified wood is said to absorb less moisture than normal wood, giving it greater stability. Trestlewood makes no specific claims that in any way attempt to quantify this benefit. Even with thermally modified wood, we take the conservative position that wood is wood and will move. ThermalBrown Lumber can sometimes be stored outside or otherwise exposed to moisture after the thermal modification process.

Standard Dimensions

a) Thickness: 1" (actual: 5/8" to 4/4") and 2" (actual: 1 1/2" to 8/4"); b) Width: random, 4" to 10"; 12" widths are also often available (actual widths can be as much as 3/4" nominal); c) Lengths: 6' to 16'.

Where more consistent thicknesses and/or widths are desired, thickness planing and/or edging processing options are often available. Boards can have small sections that fall outside standard thickness and/or width ranges. Trestlewood will often leave board ends that dip below 5/8" thick (or otherwise fall outside standard dimension ranges) to give the Buyer as much flexibility as possible, but exclude those ends when tallying board footage so as to not charge Buyer for ends that will likely need to be trimmed in the field.


Depends on species mix and other factors. The thermal modification process can cause wood to lose weight. Typically, 2.5-3.5 pounds per board foot.


Original face was generally rough-sawn (circle-sawn or band-sawn.) ThermalBrown Lumber colors vary, but are generally a range of browns. ThermalBrown Antique Lumber can include any combination of original and fresh-sawn edges (the latter are especially common where narrow boards are cut from wider boards.) Trestlewood generally does not offer a color sort which does not allow for some latitude in colors provided. The ThermalBrown Lumber program typically facilitates greater color consistency than available with Antique Barnwood Lumber.


ThermalBrown Lumber often has a "burnt" smell as a result of the thermal modification process.

Appearance Variation

Boards can vary in appearance from piece to piece and even within a piece. The characteristics described on this specification sheet generally apply to each board's featured face. The opposite face and edges can differ from the featured face in texture, coloring, and other characteristics unless otherwise noted.


The thermal modification process can give ThermalBrown Lumber characteristics including: (a) increased durability; (b) increased dimensional stability; (c) lighter weight; (d) brown color tones; (e) quicker to weather gray when exposed to sunlight; (f) increased brittleness; (g) lower mechanical/structural strength; (h) burned smell; and (i) etc. ThermalBrown Lumber should not be used in structural applications or in situations involving ground contact.

Trestlewood does not guarantee the existence (or lack) of any characteristic or make any claims about the degree to which the above-listed or any other characteristic may exist in specific ThermalBrown boards.