Lumber Options Guide For Deck Buildin
There is more to selecting the right lumber for your deck than you might expect. But knowing a little bit about which species are best for certain applications is a great place to start before heading down to the local lumber yard.
The most common types of wood used for outdoor applications such as decks are pressure treated, cedar, and redwood. Next on the list would be slightly less common wood species such as eastern white cedar, yellow cedar, cypress, and pine.
Hemlock, jack pine or yellow pine are often used for pressure treated materials because they are dense and strong for building but must be treated to increase their longevity.
Consider These Factors
When you are deciding which wood to use on your deck or outdoor project consider the following factors: species, density, grain pattern, Heartwood or Sapwood, and moisture content.
Species
Redwood
Known for its long straight grain and warm color, excellent decay resistance and ease of workability. Redwood is one of the best, if not the best natural materials for outdoor building projects.
It has become more scarce and expensive so is best used for areas of high visiblity such as decking, posts, railings, stairs or benches.
Red Cedar
Also known for its excellent weatherability and resistance to the elements. Cedar is like a cousin of redwood but is slightly less expensive. It too is becoming more scarce and so longer lengths are more expensive per foot than shorter lengths.
It also more common to see younger second growth cedar which if it contains more sapwood than heartwood is slightly less resistant to the weather. But overall its an excellent outdoor material for decks and is a beautiful decking material.
White Cedar
This eastern cousin of the western red cedar makes a great outdoor lumber but tough to find and not normally carried in the larger stores. It is common in eastern states and provinces of Canada.
The trees are smaller and grow in swampy areas and they make excellent fence posts and outdoor furniture. Since the trees are smaller the timbers tend to include more heartwood, where the grain is tighter and there are more of the natural preservative agents.
Cypress
This wood is from the swampy southern regions of the US and its availability is similar to the eastern white cedar. Try a local mill for the best quality and availability. Its not as stable as cedar or redwood but is fairly hardy.
Pressure Treated Lumber
Many species of wood that are not typically known for their decay resistance are excellent for structural integrity. Instead they are treated to make up for their natural weakness to moisture.
The most common species used in pressure treated lumber are hemlock, southern yellow pine, northern jack pine. Hemlock is commonly used in the west coast and is pierced with knife cuts before being impregnated in preservative so that the agent penetrates deeper into the wood. Treated wood tends to be denser and stronger so it will crack and check more but is perfect for substructures of decks.
Density
Depending on what your plans are, you may want to consider the density of the lumber you choose. There is trade off between density and aesthetics. Denser lumbers such as fir, hemlock, pine are more dense than redwood and cedar but they are prone to warping, splitting, splintering and checking as they dry out and age. So try to use them for substructures where they are not visible.
Less dense lumbers like redwood and cedar are too expensive to use as joist material but really excel in the visible areas like decking material, railings and furniture.
Grain Pattern
The grain of lumber is determined by how the log is cut. Straight grain, vertical or quarter grain lumber is the most stable of lumbers but more expensive because quarter cutting logs creates more waste.
Open grain or flat grain is the most common cut for lumber because it minimizes the waste but boards are more susceptible to warping or cupping. This is more of a concern for the denser lumbers than the softer woods which can be held in place with standard fasteners.
Heartwood or Sapwood
Heartwood comes from the center portion of the tree whereas sapwood comes from the outer portions. In a perfect world you should try to buy heartwood because it has tighter grain, is more stable and contains more of the natural preserving agents of the tree. The reality is that you can't always find heartwood.
Moisture Content
The more moisture in a wood board, the more it will shrink and possibly warp when it dries out. Wood that is sitting outside in the rain or humidity can sometimes have a water content of 40% or more. The best you can really hope for is around 20%.
A good test is to take a nail and drive it into the board and see if water is excreted. If it does, that board needs to dry out a bit more before you build with it. Or just expect that it will shrink more as it dries out.
So now you should have a good idea of what to consider for the lumber options as you plan your wood deck, fence or outdoor structure.