Timbers are beams/posts that are typically larger than 4x6 in dimension. They are available in a wide variety of sizes and can be special ordered in any exact size you may care to specify given the necessary lead times. Timbers are generally available locally in various grades of Douglas Fir, with Redwood, Cedar and treated wood options also available. Some alternatives to solid timbers are Laminated Veneer Lumber (LVL), Glued Laminated Timber (Glulams) and Parallel Strand Lumber (PSL).
Timbers are generally readily available in lengths ranging from 8' to 24' (in 2' multiples). Longer lengths are available at times; please check availability before getting locked into a longer length. However, lengths over 20' do carry a significant price premium. “Normal” sizes include 3x12, 4x6, 4x8, 4x12, 6x6, 6x8, 6x10, 6x12, 6x14, 8x8, 8x10, 8x12, and 2x12. Timbers come in two types: S4S (smooth four sides) and rough sawn.
Rough sawn vs. Smooth sawn
Rough sawn timbers will be rough sawn (think similar to a cedar fence board) and close to the full measure. This means that an 8x8 will net out to be very close to a true 8”x8”. They are probably green – meaning no drying on the product has been done – and more likely to split, crack warp and twist. S4S timbers will be nominal sized, for example, a 6x6 will measure 5-1/2” x 5-1/2”. S4S timbers may be some variation of air dried, kiln dried or air-seasoned. Any of these drying methods will gain you a more stable timber. Very few timbers in the marketplace are dried to the core (“core-dried”). Most timbers are at best – kiln dried, a process drying the piece to a 1” penetration. S4S timbers will, of course, be smooth sawn. S4S and rough sawn timbers are similar in price; however, deciding factors may be the cost and availability of hangers for rough sawn material, these hangers run 30-50% more and are less likely to be readily available.
Probably the most important consideration on timbers is the free of heart center (FOHC) content/factor. This is the percentage of timbers that will contain the heart center. Heart center is the dead center of the tree and should be avoided if possible. On smaller sizes (6x6), the FOHC factor can be as high as 100%; on larger sizes (12x12) having the heart center is virtually unavoidable. The reason to avoid the heart center is that any board or timber containing all/part of the center of the tree is virtually guaranteed to “check” or crack as it dries unevenly. These checks will radiate out from what was the center of the tree. The funny thing about timbers having the heart center is that they will be among the best looking timbers to begin with – this makes sense since they are made from the tree’s center, further away from the branches (knots) and protected by the bark (insect damage). Timbers that miss the heart center will dry out more evenly and hence with less checking. While these checks generally do not impact the strength of that timber, they certainly can detract from its appearance. Regardless of FOHC content, grade or initial appearance, ANY board/timber can and will crack, warp, twist, cup and split.
Otherwise, grades on timbers are primarily based on their appearance; better appearance will dictate a higher grade (and price).
The timbers most readily available in the Denver area are of the Douglas Fir species. This species of trees provide a strong, economical timber. Most sizes listed above are offered in Douglas Fir, in both S4S and rough sawn varieties. Redwood is generally available in our region in only s4s type and only in 4x4, 4x6 and 6x6 sizes. Cedar can be obtainable in mostly rough sawn: 4x6, 6x6, 6x8 and 4x8 sizes. Any other species will be a special order item with at least some lead time and pricing that can be prohibitive. Treated (for rot/decay/insects) timbers are off-the-shelf locally in 4x4, 4x6 and 6x6 with a smattering of other sizes available quickly. Keep in mind that when dealing with a reputable dealer, virtually any timber can then be treated within approximately two-week turnaround.
There are many options to conventional wood timbers, including laminated veneer lumber (LVL), glued laminated timber (glulams), parallel strand lumber (PSL) and structural steel. Most of these items come in 60’ lengths to be re-cut into your specified lengths. Ask your salesperson for more information, but a quick description is listed here:
Laminated Veneer Lumber (LVL) is available in 1-3/4”, 3-1/2 and 5-1/4” thicknesses and 5-1/2”, 7-1/4”, 9-1/2” 11-7/8”, 14” 16” and 18” heights. Most commonly used for support beams in interior construction, LVLs are strong, economical and non-appearance grade beams.
Glued Laminated Timber (Glulams) can best be described as 2x lumber stacked up and glued together to make a beam. This is a very attractive alternative for exposed locations. They are available in a wide variety of sizes for interior use. Glulams are also available in a limited number of sizes in two different exterior versions. One is an Alaska White cedar variation and the other is an ACQ-treated fir version.
Parallel Strand Lumber (PSL), similar to waferboard, consists of long veneer strands laid in parallel formation and bonded together with an adhesive to form a beam. This is an immensely strong beam, but must be covered as it is not for appearance or exterior purposes.
Since most timbers are special ordered for you, returns are not allowed unless the timber is damaged by us or deficient in grade or other similar fault. As such, please consider upfront the factors involved in using timbers before ordering.
Health & Safety
The obvious safety consideration with timbers is their size and weight. There are no special safety factors to consider while using timbers except for those that have been treated.
Sizes listed are most readily available in stock at Front Range Lumber and not meant as a guarantee of stock.
|Doug Fir Smooth Sawn||8', 10', 12'||8', 10', 16'||10', 12', 16'|
|L3 or ACQ Treated||8', 10', 12'||10'||10', 12', 16'|
|ACQ Treated Landscape Timbers (green & brown)||8'|
|Rough Sawn Cedar||8', 10', 12'||8', 10', 12'||8', 10', 12', 16'|
|Con Heart Redwood||8' to 10'||16'|
|Rough Sawn Doug Fir||10', 12'||16', 20'||16'||8'|