From Engineering on June 26, 2008 in Decks and Patios
Arbors are popular and appealing shade providers for lawns, gardens, decks, patios, and anywhere a homeowner might desire shade. I have seen them from the beaches of Lake Michigan to the rocky outcroppings of the Oregon coast. Arbors, often called pergolas, are fairly simple projects that really do provide a good amount of shade. There is a small difference between arbors and pergolas which should be noted for argument’s sake. Arbors tend to be broader and may be connected to the building on one side while pergolas are always freestanding and usually narrow.
To build an arbor you will need the following materials:
- Four 6x6 posts
- Two 6x6 beams
- Rafters (usually 4x4 or 2x6)
- Lath, 2x2 or 1x2, to run over rafters
- Wood (2x4) and stakes for bracing of posts
- One post base (including anchor bolt) per post if building on concrete
- One concrete pier per post and concrete mix if building on soil
- Galvanized nails
- 10” lag bolts with washers to fasten beams to posts
- 7” lag bolts with washers to attach rafters to beams (if using 4x4)
Doing the Work
- Start by attaching posts, cut to desired length and using post bases, to concrete slab. Or, if building on soil, dig posts holes and fill with concrete. Then set concrete piers on concrete about 3 to 4 inches above grade. Cut posts to length and nail to piers.
- Use wood, stakes, and a level to brace up posts so that they are plumb in all directions. Leave these braces attached until the arbor framing is complete and everything is nailed down.
- With help, place the two beams on top of braced posts. Drill a pilot hole through the beam and down into each post. Install 10” lag bolts and washer to secure the beams at each post location.
- Install rafters across the beams. If using 4x4 rafters, drill and install 7” lags through the rafter and into the beam below. If using 2x6 rafters, it is a good idea to use extra 2x6 and install “roll blocking” between each rafter to prevent side-to-side motion. Nail rafters and blocks to beams.
- Install 1x2, 2x2 lath over rafters to provide shade. You can also use vines if you prefer a more natural look.
- When everything is nailed off, remove braces and stakes.
- Congratulations. You now have an arbor!