How to Build a Pergola on Concrete Patio | Horizon Structures

Site Preparation Guidelines for Pergolas & Pavilions

Site prep for any pergola or pavilion starts with a design that meets your local code requirements!

Did you know that pergolas and pavilions can be built with their own floor and shipped fully assembled and ready for same-day use? In these cases, site prep is exactly like that of our storage sheds.

However, most people purchase their Horizon Structures pergola or pavilion as a kit to be surface mounted onto an existing concrete patio or deck with the anchor brackets we include in the kits.

It's very important that your pergola or pavilion sits on a level surface. If your existing surface is not level, you may need to adjust the posts of the pergola or pavilion by cutting them to compensate. Read on or contact us today to find out how to build a pergola or pavilion on a concrete patio.

Patio Set-up

Do NOT attempt to anchor the support post directly on to patio pavers or flagstone.  You may have problems with cracking or movement over the long term.

The posts need to be set on a footer or directly on a concrete pad. The paver or flagstone can then be layered on top. The post skirt that comes with your kit will then cover that area for a seamless look.

Deck Set-up

Many people install their pergola or pavilion kit on a pre-existing wooden deck. 

Assuming that your deck is in good condition and was built with standard 2x10 joist construction, situate your posts so that they align with the joists (or locate a “sister” joist under the deck). Using the anchor brackets that are included with your kit, simply bolt the posts to the decking.

Again, make sure that your deck is strong enough to hold the structure. For example: a 10x14 pavilion is going to add approximately 2500 pounds of additional weight to your deck. Substandard 2x4 floor joist will not hold the extra weight without additional support or reinforcement.

When choosing a site for your new pergola or pavilion, remember, the size of the structure is measured to the outside corners of the posts. The end caps (or eave) may extend 24” beyond that. This is important to know when choosing a location for your new garden structure by taking into account pre-existing structures or landscape features.

Starting from Scratch

If you don’t have a patio or deck and are preparing a new site keep the following in mind...

Creating a reliable base (or footing) for your structure is probably one of the most important parts of your new pergola/pavilion construction - and there is no more solid a method than to cement the footings into the ground for a really strong and stable garden structure.

You can find general pier and slab foundation concepts HERE.

These have been designed using an allowable soil bearing pressure of 2000 psf. These are generic designs only. Make sure to consult with your local building department for specific foundation designs for your area.