When dealing with installing a pergola, what to do with the pergola posts is always a concern.
The answer is: it depends on your structure and site. A pergola should almost always be attached directly to a concrete pad or concrete footings.
Make sure you are below the frost line for pier depth
Give yourself plenty of room with the diameter of your footing
A good rule is at least 18" - 20" diameter with at least 3 feet deep (depending on your frostline)
With a Luxury Pergola, concrete piers are typically recommended, especially if you don't have a concrete slab already.
In this article we will go over the spacing for footers, the depth you need to achieve, and how to make sure your pergola kit doesn't get blown away in high winds.
Why are Pergola Footings Important?
A standard pergola will need less concrete to meet local building codes than a pergola that opens and closes. When a pergola opens and closes it is typically classified as both a pergola and/or a solid roof structure. These have different wind load requirements.
Additionally, you will be constrained by the material of the pergola. The Costco Mirador pergola doesn't have the same kind of wind rating that something like the Luxury Pergola has.
Almost all of the modern pergola kit options on the market will require some kind of concrete anchor for their posts.
The biggest factor for footings is to provide counterweight in high winds. You don't want your pergola structure to become a giant wing and fly away to the magical land of Oz.
Size of the Concrete Footings
The size of concrete footings comes down to how big your pergola post is are and how big your post bases are. You want to make sure you give yourself plenty of wiggle room when you pour concrete footings. Any DIY pergola kit will need to attach to some kind of strong foundation.
With a Luxury Pergola posts you have a 7x7 inch post and a 10x10 inch post base that you will need to install on a solid foundation. We recommend 20" pier footings to ensure that you have plenty of wiggle room, in case you are off a few inches when you dig footings.
Typically when you dig a hole for a pier, the pergolas will need to be supported by that piece of concrete. You need to make sure you go below the frost line for your area. You don't want the ground to heave and destroy your structure.
In Indiana (where we are based) the frost line is about 3 feet deep. This is 3 feet below undisturbed soil. We make sure we get dig deep holes for any project and even go a few inches deeper than is typically needed.
Make sure you check your local building requirements to know how deep you should dig to get below the frost line.
Where to Place Pergola Posts
Starting from ground level, you need to know where to place your concrete footer or see what the dimensions are for you concrete pad to see if any DIY structures will fit. For digging and installation, you need to place your holes in the right spot or your foundations won't be strong enough for an anchored post.
Below we have the diagrams needed for your pergola design. This shows where the center to center for all the free standing pergola options at the Luxury Pergola.
Footing Diagrams for The Luxury Pergola Kits
Below are the diagrams of the pier footings on a Luxury Pergola kit. These measurements may not be helpful when looking to square up the pier footings for other pergola posts or other pergola options.
Footing Spacing for 8x8 Pergola
Spacing for an 8x8 pergola on center to center is above. The diagonal needs to be properly measured and ensure the location of the holes are correct.
Footing Spacing for 8x9 Pergola
Footing Spacing for 8x10 Pergola
Footing Spacing for 8x11 Pergola
Footing Spacing for 8x12 Pergola
Footing Spacing for 8x13 Pergola
Footings Spacing for 8x14 Pergola
Footings Spacing for 8x15 Pergola
Footings Spacing for 8x16 Pergola
Footings Spacing for 8x17 Pergola
Footings Spacing for 8x18 Pergola
Footings Spacing for 8x19 Pergola
Footings Spacing for 8x20 Pergola
Footings Spacing for 10x10 Pergola
Footings Spacing for 10x11 Pergola
Footings Spacing for 10x12 Pergola
Footings Spacing for 10x13 Pergola
Footings Spacing for 10x14 Pergola
Footings Spacing for 10x15 Pergola
Footings Spacing for 10x16 Pergola
Footings Spacing for 10x17 Pergola
Footings Spacing for 10x18 Pergola
Footings Spacing for 10x19 Pergola
Footings Spacing for 10x20 Pergola
Footings Spacing for 12x12 Pergola
Footings Spacing for 12x13 Pergola
Footings Spacing for 12x14 Pergola
Footings Spacing for 12x15 Pergola
Footings Spacing for 12x16 Pergola
Footings Spacing for 12x17 Pergola
Footings Spacing for 12x18 Pergola
Footings Spacing for 12x19 Pergola
Footings Spacing for 12x20 Pergola
In short, you need to make sure you have the footings space properly and the weight of the columns need to be enough to support the pergola from heavy snow and winds.