Don Vandervort, Head Homeboy, has written more than 30 DIY home improvement books, been a segment host on HGTV, served as MSN.com's home improvement expert and written countless magazine articles.
The main structural members of patio and deck overheads are posts or columns and beams, which run from post to post or from post to ledger. The beams support the roof rafters or joists, which in turn hold the roofing material.
Minimum sizes of posts and beams are set by engineering requirements and are strictly governed by local building codes.
Before beginning construction, consider finishing all of the lumber you will be using. In most cases, it's much easier to apply a finish to the lumber when it's sitting on sawhorses than when you're standing on top of a ladder. If you prefinish the wood, plan to touch it up after construction is complete.
Posts & Columns Posts and columns may be made from several types of materials. Here we look at the most common: solid lumber such as 4 by 4s, 6 by 6s, and 8 by 8s. Sometimes they'e built up from more than one size of lumber.
Any post that will touch the ground should be pressure-treated for decay resistance. Posts offer plenty of latitude for detailing—you can rout them, cut them, build up interesting profiles, or nail on decorative pieces to add visual interest.
Beams Beams can be solid lumber or be built from lengths of 2-by lumber nailed together with 1/2-inch pressure-treated plywood spacers in between (this forms a 3 1/2-inch-thick beam that is equal to the width of a 4-by post). A built-up beam is easiest to handle because you can assemble it near its final destination, but making one involves a little more labor. In highly visible areas, a single, solid beam generally looks better.
You can also build up a 3-inch-wide beam without spacers. Just nail together the two boards by driving 10d galvanized nails along both sides every 16 inches, staggering them as shown below.
Apply a bead of silicone caulk to the joint between the boards to prevent moisture from seeping between them. Be sure the crowns (the "high" side of a curve or warp along the edge of a board) on the pieces align; then, when you mount the beam on the posts, place the crown side up.
If you must assemble a long, built-up beam from shorter lengths, stagger the joints between successive layers and plan for each of these joints to fall directly over a post.
Some designs use paired 2-by joists to substitute for beams. Generally speaking, these partnered beams have a less weighty, airier appearance and are easier to handle than a single beam.
Patio Roofs & Gazebos All you need to know about building outdoor structures, from an inspirational gallery for unique ways to extend your living space outdoors, to step-by-step photo sequences to build an outdoor structure precisely suited to your needs.
The main structural members of patio and deck overheads are posts or columns and beams, which run from post to post or from post to ledger. The beams support the roof rafters or joists, which in turn hold the roofing material.
