With the post hole digger, dig 3 feet down or below your area's frost line, at each of the six staked points. Scatter a bed of crushed gravel about 4 inches thick at the bottom of each hole. Set one post in each hole, first tamping down the gravel with the post. Hold a post so that it is plumb, then pour dry ready-mix concrete around the post.
In general, posts should be spaced no more than 8 feet apart. Some builders position them every 4 feet for a completely rigid frame. The maximum distance between footings is determined by the size of your joist material. Here is a list of some common joist sizes and maximum spans. A span is the unsupported distance between two 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.
The distance between posts is dictated by the size of prebuilt panels, horizontal rails or local building regulations. Typically, spacing is between 5 feet and 8 feet. For prebuilt panel kits, the manufacturer will recommend post spacing, depending on whether the panels fit on the face or between the posts.
Great pergola. My question is to make a pergola 16 X 11.5 feet would I have to use bigger post than 4×4s and can I use 2×8 for joist and 2×6 for the beams. There would be three 4×4s on the 11.5 feet side with six 18 feet joists to make the 16 feet. Then use the many 13.5 foot beams to finish it off.
The thickness of the posts should also be taken into consideration when planning for the space in between the posts or in between the wall and posts. The Big Kahuna, The Sombrero, and The Fedora pergola kits all have 6 posts, and The Brim pergola kits have 4 posts.
On the 8-foot sides, that makes a spacing of 4 feet between posts, and on the 12-foot sides, the post spacing is 6 feet, which is the upper limit of the code requirement. That's a total of 8 posts.
what is max distance between posts using 2x12x20 foot beams for a pergola contact on your posts and you will enjoy your pergola for decades. span 12 feet
Unless you are working in structural steel and we do work with that quite often , spans should be limited to twenty feet between posts to avoid special orders and special prices that go with extra-long lumber. Also, the larger the pergola, the higher the rafters should be to keep things in proportion.