Specification Sheet #7230 - ThermalAged Brown 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.

ThermalAged Brown Lumber is lumber which is run through a thermal modification process in a thermal kiln at high temperatures (typically 180 degrees Celsius to 220 degrees Celsius.) 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.

Nails 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.

Unlimited knots; some tight, some loose or fallen out

Unlimited as long as board is sound

Mixed

Thermally modified to a low moisture content. The thermal modification process alters the treated wood at a cellular level in a way that increases its dimensional stability, moisture resistance, and rot/decay resistance without the use of chemicals. Even with thermally modified wood, Trestlewood takes the conservative position that wood is wood and will move. ThermalAged Brown Lumber is sometimes stored outside or otherwise exposed to moisture after the thermal modification process.

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 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.

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.) ThermalAged Brown Lumber colors vary, but are generally a range of browns. All else being equal, higher thermal kiln temperatures result in darker brown tones. 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. Lighter brown color runs done at lower kiln temperatures often result in fewer performance benefits (dimensional stability, moisture resistance, rot/decay resistance, etc) than runs done at higher kiln temperatures. 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.

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

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 coloring of ThermalAged Brown Lumber generally extends through the full thickness of the board.

When 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 (standard face widths: 4.625", 6.375", 8.375"; target thickness: 0.72" (23/32") (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 (standard face widths: 3", 4.75", 6.5", 8.5";standard target thickness: 0.72" (23/32") (a weathered face T&G product will naturally have some thickness variation); the fit of barnwood siding T&G is often not quite as good as flooring T&G)

Unmilled siding products (a, b, and c) are standard barnwood lumber. 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.

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.)

The thermal modification process can give ThermalAged Brown Lumber characteristics including: (a) increased durability; (b) increased dimensional stability; (c) increased decay/rot resistance; (d) increased insect resistance; (e) brown color tones; (f) lighter weight; (g) increased brittleness; (h) lower mechanical/bending strength; (i) burned smell; and (j) etc. Buyer should consult with a structural engineer before using ThermalAged Brown Lumber in structural applications. Trestlewood recommends against using ThermalAged Brown Lumber in situations involving ground contact.

ThermalAged Brown Decking is 1.5" x 5" ThermalAged Brown Lumber with one smooth-planed face and one texturized face (allowing Buyer to decide which face to feature.) The smooth face has an eased/rounded edge (1/4" radius.) There can be occasional hit-and-miss on the textured face. Lengths are random 4-16'. Consult with an engineer to make sure ThermalAged Lumber's reduced bending strength is accounted for in the design.