A pergola is a wooden structure that is used to form a partially-shaded walkway or sitting area in a garden or as part of a backyard deck. Composed of posts supporting horizontal beams it provides a break in a large yard space. It can also be built in a weekend with a minimum of carpentry skills and a few simple materials.
Aside from being a decorative element in itself, the pergola allows you to suspend flower pots and provides support for climbing plants.
The following project details the instructions to build a pergola on a deck.
Call the local building office to see if a permit is needed as a pergola is a large enough structure that might need one. In addition, inquire as to the type of footing that is allowed. And most important, make sure to contact the utility companies before digging to avoid disruptions to household service or safety of the builders.
1.1 Draw the shape you want for the ends of the rafters and headers on a piece of cardboard.
1.2 Apply the design you choose to both ends of the headers
1.3 Apply the design to one end only of the rafters. Be systematic and symmetric in applying your design.
1.4 Cut the design on the boards with a jigsaw.
1.5 Measure the distance between the end (house side) and the first 2" × 8" of the header.
1.6 Trace the shape of the two notches in the rafter that will be recessed in the header. The notches must be 1½” wide and 3" deep and be separated by a space equivalent to the width of the column or post. You can replace both these notches by a wider one that would be the width of the two 2" × 8" boards and the post i.e.: 6½".
1.7 Cut the notches with a jigsaw.
2.1 Determine the location of the metal bearing brackets, one at each corner.
2.2 Install the metal bearing brackets to the patio or deck floor. The 4"× 4" posts will then be installed in these brackets.
3.1 Determine the location of the joist. It should be higher than the header but at the same height as the rafter will be.
3.2 Start from the centre of the end joist, and mark the location toe the metal joist hanger at every 14" centre to centre. You're likely to find that the spaces at both ends will be narrower than 14".
3.3 Attach the metal joist hanger to the end joist. The rafters will eventually be installed in these hangers.
3.4 Attach the pre-cut end joist to the house. For siding, aluminum, vinyl or wood, you’ll need to locate the various elements of the structure. Studs are generally 16" apart (centre to centre) on either side of a door. Use lag screws. For masonry, use masonry anchors.
4.1 Make sure both posts are exactly the same length and fit with the height of the joist
4.2 Mark the locations of the headers that will support the rafters on both posts.
4.3 Mark the locations of the posts on the headers and drill holes.
4.4 Attach the headers to the posts using lag screws and a ratchet.
4.5 Attach the header structure and the posts to the corner brackets.
5.1 Fit the notched ends over both header boards than drop the other ends into the brackets attached to the end joist. Start from the centre going outward.
5.2 Screw the rafters into the header boards at a 45° to strengthen the structure.
5.3 Attach the outside rafters to the post with lag screws.