A pergola is an arbor with a latticework roof. It is normally built for grapes, Japanese Wisteria, or other vines of fruit or flowers. It provides shade in the garden and is used for family gatherings, including weddings. Before building a pergola, check with your local authority concerning possible building permits and conditions required. Check with utility companies concerning possible underground gas, water and electrical lines. In some areas, phone lines are buried with electrical lines. Remember, the actual size of the lumber is different from the nominal size of the lumber before it has been dressed or seasoned.
Determine the style pergola you intend to build. Consider overall height and width of your pergola according to your local and community building codes. Choose an area that is pleasing to you for your pergola that does not have buried utility lines.
Tell the lumber yard what you are building and take their advice about the type lumber you will need to use where you live. Humidity, termites, extreme cold temperatures, and building codes will also determine what type lumber to use.
Cut eight stakes 2 feet long from the (2 x 4) wood stock. Make a point at one end of each stake. Drive a stake with builder's string line at the first corner. Lay a right-triangle along a 2 x 2 board at the pergola's front edge. Pull the string to the back corner of your pergola to align the front angle at 90 degrees and place a stake at the back corner.
Repeat step three for the other side of the pergola, driving stakes to mark the post positions. Midway between the front and back post on each side, drive a stake. Make a level mark on each stake and proceed with the temporary framework structure.
Nail the (1 x 4) batter boards to the stakes such that the top of the batter boards are flush with the level lines marked on the stakes.
Use a posthole digger to dig four holes that are three feet deep. Add three inches of crushed rock to the bottom of the holes to prevent rotting. Drop the posts into the holes and use a level to get the posts plumb. Use stakes on all sides to keep the posts vertical.
Add Quickcrete to each hole until it is 1/2 inch from the top. Add one gallon of water to each post hole. Quickcrete does not need mixing. Attach supports to hold the front and back beams in place as you pre-drill holes through the beams and posts for the carriage bolts.
Push the bolts through the holes with metal mallets and secure the bolts with nuts and washers. Tighten the bolts. Use spacers to lay out the rafters equal distance from each other. Secure rafters with metal hurricane clips with hot-dipped galvanised bracket nails, according to Ron Hazelton.
Remove temporary batter boards after everything has been secured. Use spacer boards, randomly, between rafters for more support when heavy vines are grown.
Check several building supply stores before buying materials for a pergola. Prices vary widely according to type of lumbar used, how many beams you use, and whether you add fancy woodwork to your pergola. According to website DIY Network, a 10 by 10 foot pergola with four posts made of treated pine can cost between £650.00 and £1,625.00 as of May, 2010.
The average cost, according to Ron Hazelton, for the same pergola is £1,559.30, as of May, 2010. ( Reference 3 )
Build Eazy recommends checking often throughout the project to ensure everything is square, plumb and level. Pergola kits can be purchased from most builder supply companies, taking the guesswork out of the material list.