We’re often asked, “What is the best wood for timber framing?” Although it’s estimated that 60% of timber frames in North America are built from Douglas Fir, there are other timber frame wood species which may work as well, or better, for your building project.
So, here in one place, is exactly how to select a timber specie from the most common woods used in timber framing. Perhaps as important, you’ll learn how to specify the other important wood characteristics for a timber frame–things like timber grade, moisture content, heart content, and surface texture.
Common Timber Abbreviations:
AD = air dried
BH = boxed heart
FOHC = Free of Heart Center
Glulam = glued laminated timber
GRN = green (freshly cut, wet)
HT = heat treated (reclaimed wood is sometimes heat treated to kill bugs)
KD = kiln dried (when timber is dried in a conventional kiln, only the outer inch or so is dried)
PAD = partly air dried
PT = pressure treated (with chemicals to resist decay)
RFKD = radio frequency kiln dried (dry to the core, but only applicable to Douglas Fir
S4S = surfaced four sides
S-Dry = surface dry
TAD = thoroughly air dried
Characteristics of Common Timber Frame Wood Species
For each of the common woods used in timber framing below, we’ve noted the characteristics, decay resistance, notes specific to timber framing–as well as an indication of the relative cost ($ less costly, $$ average, $$$ more costly). Some of the information below is adopted from the USDA Forest Service’s Forest Products Laboratory book: Wood Handbook–Wood as an Engineering Material.
BALDCYPRESS (Taxodium distichum)
Also known as southern-cypress,tidewater red-cypress, yellow-cypress (inland), and white-cypress. Southern US softwood; moderately heavy, moderately strong and moderately hard. Old growth is resistant or very resistant to decay, but no longer readily available. Second growth is moderately resistant to decay. Sapwood is narrow and white colored. Heartwood color varies from light yellowish to reddish brown color. Shrinkage is moderately low but somewhat higher than the cedars. Difficult to obtain longer than 20′. $$.
PORT ORFORD CEDAR (Chamaecyparis lawsoniana)
Straight-grained, fragrant and durable. A softwood, which grows along the Pacific Coast from Coos Bay, Oregon southward to California in a narrow band less than 40 miles wide. Fine texture, generally straight grained, with a pleasant spicy odor (it reminds us of ginger). Moderately lightweight, stiff, moderately strong and hard. The heartwood is highly resistant to decay. Moderate shrinkage with little tendency to warp. Prized by Japanese temple builders as it resembles Japan’s sacred, and rare, Hinoki Cedar. $$
WESTERN RED CEDAR (Thujaplicata)
Straight grained, low shrinkage, durable. A softwood which grows in the Pacific Northwest and along the Pacific Coast to Alaska. The heartwood is reddish or pinkish brown to dull brown, and the sapwood is nearly white (but narrow, and usually less than 1″ wide). Very low shrinkage, lightweight, moderately soft, low in strength. The heartwood is very resistant to decay because the chemical substance Thujaplicin, found in mature Western Red Cedar trees, is a natural fungicide. $$$
EASTERN WHITE PINE (Pinus strobus)
The “moderate” timber: moderately soft, moderately low in strength, moderately durable, and moderate shrinkage. A softwood which grows from Maine to northern Georgia and in the Great Lake States. Challenging to obtain graded for structural timber framing. Creamy white or pale straw to light reddish brown. Darkens with time to a light caramel color, then after many years to a deep rich golden tan. Stains well. $