The timber cannot be pressure treated with copper, chromium and arsenic (CCA), but can be boron treated to Hazard Classes H3.1 and H1.2. Once you’ve picked it up it’s hard to put it down! Douglas Fir is the strongest of our homegrown softwoods. DOUGLASFIRPLYWOOD (EighthEdition) COMMERCIALSTANDARDCS45-48 [SupersedesCS45-47] EffectiveDateforNewProductionFromNovemberI,1948 ARECORDEDVOLUNTARYSTANDARD … Douglas fir plywood comes in three basic grades. Despite the name “Douglas Fir,” the tree is actually part of the Hemlock family. Douglas Fir Pseudotsuga menziesii Douglas firs are among the tallest trees on the continent, second only to coastal redwoods. East of the Cascades, Larch grows intermixed with Doug Fir and marketed as “DF-L”. No. Both red oak and white oak are harder than Douglas-fir wood. always be confirmed with suppliers prior to specifying. 10.1007/s00107-016-1149-4. Timbers Douglas Fir timbers are a great choice when large structural beams are required. hal-01530963 Modelling mechanical properties of spruce and Douglas r timber by means of X-ray and grain angle … 3. Thanks to their high-quality appearance, predictable strength, and reasonable price point, they are an excellent fit for your big timber needs. 1 and No. In comparison to other species ranging from 1200 ~ 1500 for Select Structural grades. Understanding Douglas Fir's Strengths & Weaknesses. A strength class is simply a grade with associated numbers for strength, stiffness and density that can be used in design. Structural Joists & Planks (2x5 through 4x18, intended for engineering applications for lumber 5" and wider, such as floor and ceiling joists, rafters, headers, small beams, trusses and general framing applications. Pros. Its tight knot structure and close grain make it as beautiful as it is functional, with appearance grades available in both clear and tight knot. More than 5 knots and the lumber will not make top grade and will downgraded to construction grade, which is of course worth considerably less money. Outside of traditional timber framed structures, Douglas Fir wood has great applications in thinner stock sizes too. Douglas Fir is ideal for outdoor or indoor applications where strength is needed for a structural purpose. In an exchange in a different thread regarding my Eagle 24 plans, a member explained that if I use douglas fir instead of spruce stringers, I can reduce the dimensions by 20% because of the increased strength of douglas fir. The timber lacks termite-resistance and sapwood is susceptible to lyctid borer attack. It has the ability to hold nails and screws as well as glue. Strength: Douglas-fir is an excellent framing timber. Douglas Fir is an excellent construction grade lumber utilized for strength and apperance purposes. Properties of european planted trees (young and with a rapid growth) which are mentionned in this sheet are different from those of the "Oregon pine" (old and with a slow growth) coming from its original growing area. 3 to 6 inches in diameter, were tested in third-point bending and in Compression parallel to the grain. Douglas Fir Timbers. Douglas fir is only moderately durable, and both sapwood and heartwood resist impregnation with preservatives. AltruFir’s CVG Douglas fir flooring is a C & BTR grade, and is characterized by having 10-25 rings per inch and knots no larger than ¾” in diameter. Douglas Fir, friend of the forester, sawmiller and woodworker alike but taken for granted in it’s own back yard! Douglas Fir, Ponderosa Pine, White Fir and Western Red Cedar are the most common single species sold as dimension lumber products. Douglas fir is commonly found as sawn timber in weather-protected heavy construction applications such as mining timbers, posts and poles. the grade stamp. One method is suggested. Post Nov 18, 2016 #1 2016-11-18T02:48. Strength class is usually specified with reference to EN338 (e.g. Pseudotsuga Menziessii is the latin name for Douglas Fir which originates from USA and Canada, this is also grown in the UK, New Zealand and Australia. Douglas Fir sapwood is whitish like pine. Durability: Douglas-fir heartwood is rated as Class 3 durability and can be used for above-ground purposes, but the sapwood is non-durable. Availability of large size and long length timbers should . Sizes tested ranged from nominal 51 by 102 mm to 102 by 256 mm. Consider how a round log is converted into rectangular lumber. DFP is produced to the manufacturing standard CSA O121 Douglas fir plywood, where front and back faces are Douglas Fir. Throughout the learning curve that J. Gibson McIlvain has gone through in our decade-long relationship with carrying softwoods, we’ve come to understand the up sides and down sides of using Douglas Fir. Traditional stress grades (‘F’ grades) based on strength grouping. Overall Similarities. 494 129 5. As far as strength properties are concerned, the choice between any two lots of southern pine and Douglas -fir will depend upon the grade and density of the timber composing each lot. For each size and grade combination, 4 samples of 60 pieces were selected for evaluations of compression strength at 4 … Some grades are selected for appearance and strength. Spruce. Lumber Yard Checklist. The hardness and strength factors will differ a bit if you are considering Douglas fir vs. eastern white pine or Ponderosa pine vs. Douglas fir. AB is as close to perfect as it comes. Grades are: SELECT STRUCTURAL No.1 & BTR (in Douglas Fir, Douglas Fir-Larch, or Hem-Fir species only.) Tensile strengths of Douglas-fir and hem-fir were not sig- nificantly different. The wood passes lightness and tensile strength tests with flying colors. The prices paid for top grade Douglas fir result form the extensive harvesting of the last of the old growth forests in Western North America. Doug Fir lumber products are identified by region. Other grades are designed for serviceability with strength and appearance qualities to provide reliable and economical construction. They average from 45 to 60 metres in height, from 600 to 1850 mm in diameter, and are found at elevations ranging from sea level to 1830 metres. Products from trees growing west of the Cascade Crest are simply identified as “DF” on the grade stamp. It has the ability to season well in place because of its natural dimensional stability. Additional tests were conducted on air-dried solid-sawn Douglas Fir and Southern Pine specimens. Inland, Douglas Fir often grows in stands with Western Larch which shares similar structural performance characteristics. Appearance and structural grades are very different so it is important to specify which is necessary for your particular project. Douglas-fir is a large tree, reaching 85 metres on BC’s coast and 42 metres in the Interior. The difference in strength between any of these pines and Douglas-fir is not so great but that low density pieces of the one species are weaker than the average for the other species. Douglas fir is recognized for its superior strength-to-weight ratio and has the highest ratings of any western softwood for extreme fiber stress in bending. A perfect choice for outdoor patio covers, pergolas, or pavilions – either stained or painted. Doug Fir timbers are a growing breed of wood timbers for both interior and exterior applications in the Midwest. 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