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How to Build a Pergola

Construction How-To, Porches and Gazebos July 20, 2016 Sonia










Add a stylish enhancement to your back yard.

By Matt Weber

Pergolas have long been popular additions to a home because they add style and character to the outdoor living space. They can vary in size and design to fit different landscapes, and have the added benefit of breaking up the sunlight (but not too much) in areas of the yard where people like to relax and entertain.

That was Steve and Blakeney’s reason to add a new pergola to their back yard. The rear patio of the home made a nice place to congregate, complete with a fire pit, ample seating and even a hot tub. The hot tub was exposed to direct sunlight, however, which can get overbearing at the height of a sweltering Alabama summer. A pergola offered a good solution to decorate the patio and mitigate the heat and brightness of the shining sun.

Pergolas are generally constructed with four support posts connected at the top with rafters and decorative cross-members. Typically built of treated lumber, cedar or redwood, they are fairly simple structures in design, but you should keep some basic building practices in mind to ensure construction of a pergola lasts for years to come.

Support Posts

To adequately support the lumber overhead as well as give the pergola a sturdy look, you’ll probably need to use 6×6 for the support posts. For a very small pergola with only 4 to 6 feet between posts, 4×4 supports will work. For anything larger, though, the 6×6 stock will not only offer a beefier look and greater carrying capacity, but 6×6 also resists the twisting associated with the more spindly 4x4s. Make sure the post material is rated for ground contact.

To integrate a pergola into the existing landscape, they’re usually built square to the house or the nearest structure. Lay out the post locations with stakes and string using the 3-4-5 method to ensure square corners.

Most pergolas are constructed square to the nearest building structure.

Most pergolas are constructed square to the nearest building structure.

Dig the post holes according to the depth determined by your local building codes to get beneath the frost line in your area. Compact the soil at the bottom of the post holes, add gravel for drainage, then secure the post bottom with concrete while ensuring the posts are plumb and aligned perfectly square with the adjacent post locations. Double and triple check your measurements during installation. Using string along the face of the posts can help guide a square layout.

The posts are made of 6x6 treated lumber rated for ground contact.

The posts are made of 6×6 treated lumber rated for ground contact.

Setting a tall 6×6 post is a two-man job. It helps to have one man plumb and align the post while a second worker secured the bottom with concrete and attached the brace boards that hold the post plumb while the concrete dries. The braces are made of