Building an arbor
Building an arbor is a big job, but it can add an elegant and formal touch to any landscape. It's a big job made of several smaller ones, however, including setting posts, trimming them, attaching beams, and attaching rafters. Double-check your work as you go. A small error at ground level can make a big difference at the top of a post. Building starts with the posts. You can install them in the ground and fill the hole with concrete, or you can pour a concrete pier and rest the posts on top of it.
- INSTALL THE SECOND SET OF BEAMS
- LAY OUT THE RAFTERS
- SCREW THE RAFTER IN PLACE
- ATTACH THE REMAINING RAFTERS
- CUT THE SLATES TO LENGTH
- ATTACH RAILS
- BUILD A FRAME
Drive batterboards into the ground 2 to 3 feet beyond each post's position. Stretch mason's line between the batterboards, outlining the edges of the arbor. Level the lines with a line level. To square a corner, mark one of the mason's lines 3 feet and the other 4 feet from where the lines cross. Slide the lines on the batterboards until the distance between the points is exactly 5 feet. The corner is now square. Mark the ground at each corner, drop a plumb bob and mark the ground below it with powdered chalk or sand. Mark the position of the mason's lines on the crosspieces. Untie the lines, but leave the batterboards in place.
Use a posthole digger or power auger to dig holes at the marked spots. Dig at least 10 inches deeper than half the exposed height of the posts. For example, a post that's 8 feet tall needs to sit in a hole that's 4 feet 10 inches deep. Shovel in 4 inches of gravel, tamp it, pour in a 6-inch layer of concrete, and let it dry. Retie the mason's lines and slide them on the crosspieces to mark the outside edges of the posts. Set each post into its hole, plumb it with a fence post or regular level, and brace it with 1x4s and 2x4 stakes. Pour the concrete and work a 2x4 up and down in it to remove air pockets. Slope the top of the concrete so water drains away from the posts. Let the concrete cure for two to three days.
LAY OUT THE CUTS
Mark the final height on one post and tack mason’s line to it at that point. Run the line to the next post, level it with a line level, and mark the height on the post. Repeat the process for the remaining posts. Clamp a speed square to the post at the measurement that compensates for the distance between the edge of the circular saw’s base and the blade so the cut will be on your mark. Set the saw’s base place against the cutting guide and cut into the post. The blade won’t cut all the way through, so finish the cut with a handsaw. (the cutoff will fly off wildly if you finish the cut with the circular saw.) Cut the other posts the same way.
CUT THE BEAMS TO LENGTH
Before installing beams, check with your local building department for code specifications. Usually 2x8s are installed, one on each side of the posts. If you want a decorative effect, extend the beams beyond the post and cut a shape in them. Make a cardboard pattern of the shape, trace it onto a board, and make the cut wit ha saber saw. Use the board as a template to cut the other beams and the rafters. With a helper, screw a beam in place on one side of the posts so it’s flush with the top of the posts. Place a second beam on the other side. Fit two 4x4 spacers between the double beams as reinforcement and screw them in place on both sides with 3-inch screws.
DRILL FOR BOLTS
Drill two ¼-inch holes per post that run through a beam into the post and out through the second beam. Offset holes to avoid weakening the wood. Put a washer over a carriage bolt, put the bolt through the hole, slip on a washer and nut, and tighten. Tack a board to the post under each end of the double beam. Level the board and tack it to the adjacent post. The two boards will serve as temporary support for the other double beam and ensure that the two beams are square and level.
INSTALL THE SECOND SET OF BEAMS
Rest the second set of beams one at a time on the supports. Drill and counterbore holes as before, then install carriage bolts. Remove the temporary support once the second beam has been installed.
LAY OUT THE RAFTERS
Start wit hthe end rafters, positioning them so the outside edges align with the outside edge of a post. Measure, then space the rest of the rafters between the end rafters at 16 inches on center. Cut the rafters 24 inches longer overall than the distance between beams. Cut any desired design at the ends of the rafters. Place an end rafter on the beams and adjust it so the overhang is equal at both ends.
SCREW THE RAFTER IN PLACE
Drill starter holes for the screws at an angle through the rafter, making the holes a bit smaller than the diameter of the screw. Repeat on the other end. Tack a nail to each end of the end rafters and pull a mason’s line taut between the nails. The lines will help align the ends of the rest of the rafters.
ATTACH THE REMAINING RAFTERS
Lace the rafters one at a time, spacing them according to the marks you made on the beams. Align the ends of each rafter wit h the mason’s lines, then drill starter holes and toenail the rafter in place with 3-inch deck screws. Repeat, screwing all the rafters in place. Cut miters on both ends of short 2x4’s to make braces for the rafters. Drill 3/8-inch-diameter holes through each brace, then drill through the brace wit ha ¼-inch-diameter bit to create a pilot hole. Drive 3/8x3-inch lag screws through the holes. Seal any gaps at the joints with exterior caulk.
CUT THE SLATES TO LENGTH
Cut 1x2 slats to length by clamping several together at a time and cutting them with a circular saw. Locate the centerpoint of the rafters and snap a chalk line across them. Align the center of the first slat with the chalk line on the rafters. Drill holes into the slat with a combination countersink bit and screw the slat into place wit h#8 2-inch deck screws. Use a slat as a spacer to lay out the next slat and screw it in place. Repeat across the entire roof.
Screw 2x4 top and bottom rails to the posts with galvanized #8 2 ½-inch deck screws. Place 1x1 stops along the outside edges of the posts and rails to support the lattice panel. Secure the stops with galvanized #8 2 ½-inch deck screws. Place the lattice panel against the stops and install1x1 stops along the other side, sandwiching the panel. As a decorative touch, add four mitered 2x2s around each post directly below the beams. Cut the pieces to size, then drill pilot holes and nail each piece to the post with galvanized #8 2 ½-inch finishing nails.
BUILD A FRAME
Construct a frame of 2x2s and screw it to the rafters with #8 2 ½-inch deck screws. Nail 2x2 supports every 2 feet inside the frame so they’re at right angles to the rafters. Unroll the material onto the frame and tack two adjacent corners to the frame. Cut 1x2s to fit over the 2x2s. Lay the 1x2s in place. Have a helper pull the material tight while you screw the first 1x2 to the rafters wit h#8 2-inch deck screws. Pull the material tight and screw in the next 1x2, continuing this way to the other end.
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Due to differing conditions, tools, and individual skills, The Home Depot® assumes no responsibility for any damages, injuries suffered, or losses incurred as a result of attempting to replicate any of the home improvement ideas portrayed in this website Before beginning any home improvement project, review it thoroughly to ensure you or your contractor can finish the project and if any doubts or questions remain, consult local experts or authorities. Because codes and regulations vary greatly, you always should check with authorities to ensure that your project complies with all applicable local codes and regulations. Always read and observe all of the safety precautions provided by any tool or equipment manufacturer, and follow all accepted safety procedures.
- fiber tube forms
- #8 3-inch deck screws
- post anchors
- shade fabric
- duplex nails
- chalk line
- post level
- speed square
- drill and bits