How to select Douglas Fir Timber
Douglas fir is a highly prized lumber for its strength and durability, but it is important to know how to choose the proper type of fir for the job. Fir is growing in popularity as a choice building product across the globe, and yet the average lumber consumer doesn’t know how to pick a good fir.
When selecting a fir the most important thing to look at in all cases is the size of the knot. A large knot is almost worthless, with little strength or durability to it. Always look for the tightest knot possible to maximize the output of your timber.
The second most important thing to look at in Douglas fir timber is the density and straightness of the grain. The straighter and richer the grain the better the timber will be able to displace weight and pressure.
The physical appearance may often be an important factor in the decision of which timber to purchase. Old growth and new growth firs are very different in appearance. A young tree of rapid growth will generally appear to have heartwood with a reddish colour. Old growth firs will usually have very narrow rings and heartwood that is an almost yellowy brown. Unlike many types of timber, a young Douglas fir will not usually be of any worse quality than a mature fir.
It is also important to consider the method of drying when choosing a Douglas fir. If your timber will be in contact with the ground, it is imperative that it be given the Brown and Rutherford preservative pressure treatment. The most common ways to dry fir is through kiln drying or air drying. Kiln drying is much better at keeping the timber uniform and stopping it from splitting. That is why all Brown & Ruthorford Dougals fir is kiln dried and closely inspected for quality by our partner mills.