ThermalAged Brown Lumber  

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ThermalAged Brown Lumber - Product Info

ThermalAged Brown Lumber is lumber which has been run through a thermal modification process to give it enhanced durability and other characteristics and nice brown tones.

Trestlewood generally targets medium to dark brown tones in its standard ThermalAged Brown Lumber program. Custom runs of lighter brown tones can often be done with orders involving at least 7,500 board feet of lumber.

ThermalAged Brown Lumber provides the opportunity for the most color consistency among Trestlewood's brown aged/weathered lumber products. You should still expect some color variation (and variation in other characteristics) from board to board. ThermalAged Brown coloring generally extends throughout the full board thickness, allowing you to cut ThermalAged Brown boards and have the resulting board faces be quite consistent in color.

ThermalAged Brown Lumber tends to be Trestlewood's most stable lumber product. If your application/preference makes it important to minimize wood expansion and contraction, we recommend that you strongly consider ThermalAged Brown Lumber.

Specification Sheet #7230 - ThermalAged Brown Lumber
SpeciesMixed 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.
SourceThermalAged Brown Lumber is lumber which is run through a thermal modification process. Lumber used in Trestlewood's ThermalAged Brown Lumber program can be i) new lumber, 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) lumber reclaimed from various salvage projects. Lumber which is antique/reclaimed will generally be labeled as such.
Metal/HolesNails and fasteners are generally removed (if they existed in the first place.) ThermalAged Brown Lumber which comes from new lumber will often not have nail or other fastener holes.
KnotsUnlimited knots; some tight, some loose or fallen out
Checking/CracksUnlimited as long as board is sound
Grain PatternMixed
Moisture Content/StabilityThermally 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. ThermalAged Brown Lumber can sometimes be stored outside or otherwise exposed to moisture after the thermal modification process.
Standard Dimensionsa) 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 7/8" nominal); c) Lengths: 6' to 16'. All dimensions/lengths mentioned are for unmilled lumber.

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.
WeightDepends 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.
Surfacing/Texture/ColorsOriginal face was generally rough-sawn (circle-sawn or band-sawn.) ThermalAged Brown Lumber colors vary, but are generally a range of browns. Trestlewood typically targets medium to dark browns in its ThermalAged program. Lighter brown custom color runs can often be done in quantities of 7,500 bf and over. ThermalAged Brown 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 ThermalAged Brown Lumber program typically facilitates greater color consistency than available with Antique Barnwood Brown Lumber.
OdorThermalAged Brown Lumber often has a "burnt" smell as a result of the thermal modification process.
Appearance VariationBoards 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 coloring of ThermalAged Brown Lumber generally extends through the full thickness of the board.
Siding Product ConfigurationsWhen Trestlewood quotes 1,000 square feet of a specific siding configuration, it is quoting enough material to provide 1,000 square feet of coverage based on default installation assumptions and 0% installation falldown. Buyer should order enough product to cover anticipated installation falldown and the impact of any changes to installation assumptions. Siding configuration options include:

(a) Board to Board (common widths: 4", 6", 8", 10", mixed)
(b) Board and Batten (common board widths: 8", 10", 12"; typical batten width: 4"; assumed: installed with 2" gaps between boards)
(c) Board on Board (common widths: 6", 8", 10", mixed; assumed: installed with 1" overlap on each edge)
(d) Shiplap (common face widths: 5", 7", 9" (often actual face widths of 4 3/8" to 4 7/8", 6 3/8" to 6 7/8", 8 3/8" to 8 3/4"); target thickness often between 11/16" and 3/4"+/- for NatureAged/HarborAged/ThermalAged and between 5/8" and 3/4"+/- for Antique and WeatheredBlend (while Trestlewood will generally target one thickness for a specific batch/order of shiplap lumber, a weathered face shiplap product will naturally have some thickness variation); most commonly, 3/8" shiplap joints are milled on opposite edges and opposite sides of boards)
(e) Wedgelap w/ Rabbet (common face widths: 5" to 5 1/4" (typical actual coverage of 4 1/2" to 4 3/4"), 7" to 7 1/4" (6 1/2" to 6 3/4"), 9" to 9 1/4" (8 1/2" to 8 3/4"); typical thickness of +/- 1/4" on thin side to 3/4" or a bit less on thick side; rabbet added to thick side); stress reliefs are NOT added to the back face; this is a custom product and cannot be returned
(f) Wedgelap w/o Rabbet - this product is typically cut on a resaw and is not as exact (i.e., there will be more variation in dimensions) as Wedgelap with Rabbet. Involves cutting a wedge in as-is lumber (usually 6", 8", or 10" nominal width.) Resulting product will generally have thickness of 1/4"+ to 11/16-7/8" and width of 5.25"+, 7.25"+, or 9.25"+ (with coverage width depending on how installed on site (often 4.5"+/-, 6.5"+/-, 8.5"+/-.) Stress reliefs are NOT added to the back face. Lumber is NOT double end trimmed. The wedgelap without rabbet does not sit as flat on the wall as the wedgelap with rabbet - this likely increases the chances of cupping, splitting, and/or other movement over time. This is a custom product and cannot be returned.
(g) T&G (common face widths: 3", 5"(4.5-5"), 7"(6.5-7");target thickness often between 11/16" and 3/4"+/- for NatureAged/HarborAged/ThermalAged and between 5/8" and 3/4"+/- for Antique and WeatheredBlend (while Trestlewood will generally target one thickness for a specific batch/order of T&G lumber, a weathered face T&G product will naturally have some thickness variation); fit of barnwood siding T&G often not quite as good as flooring T&G)

Unmilled siding products (a, b, and c) are standard barnwood lumber. Targeted thicknesses and widths of milled siding products (d, e, f, and g) are generally driven by barnwood lumber inventory on hand. The milling process generally reduces but does not eliminate variation in actual thicknesses and widths (across boards and even within specific boards.) The milling process often creates additional character like loose or fallen out knots. Such defects are generally left in the boards; buyer can decide whether to install them as is, cut them out, or fill them. Kiln drying lumber prior to milling it can increase the tendency for knots to become loose during the milling process. The average length of siding boards (especially milled siding boards) will generally be less (sometimes significantly less) than the average length of lumber boards. Siding square foot prices will generally be somewhat to significantly higher than lumber board foot prices because they reflect more material and, in the case of milled products, additional processing costs.

Trestlewood makes no representations about the fitness of its products for use as siding or in any other application. It is ultimately the Buyer's responsibility to (a) determine which products (and their accompanying characteristics) are acceptable for use on its project and then to (b) make sure these products are handled and installed correctly. While Trestlewood is not a construction or installation expert, it does periodically pass on (without any guarantee of accuracy) information/resources to its customers that it thinks might provide helpful starting points to consider - see, for example, Trestlewood's 7/14/2023 blog post "Exterior Wood Siding Thoughts to Consider" and Document #240173 referenced therein.)
OtherThe thermal modification process can give ThermalAged Brown Lumber characteristics including: (a) increased durability; (b) increased dimensional stability; (c) lighter weight; (d) brown color tones; (e) increased brittleness; (f) lower mechanical/structural strength; (g) burned smell; and (h) etc. ThermalAged Brown 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 ThermalAged Brown boards.
Note: Please study specification sheets to familiarize yourself with product characteristics and their possible implications for your application.