Building a Pergola on a Deck
Building a pergola over a deck is the best of both worlds because you get a great outdoor living area that is protected from the weather. Building a pergola over a deck can be built during the construction of the deck or added after the once the deck is complete. Building a pergola over a deck is fairly straight forward and there are two main methods.
- Build your pergola during the construction of the deck. In this method the deck and pergola share the posts on the outside of the pergola and deck.
- Build your pergola by adding new posts on top of the deck or running new post through the deck from the ground to the top of the pergola.
Build a pergola and deck at the same time (option one)
This method of building a pergola over a deck is the most common because the deck and pergola can share common posts and this makes both the pergola and deck quicker to build.
Step one: Pergola and deck set out
In most cases the set out for the deck and pergola will be the same. Mark out the area using builder’s string and check that it is square to the house. If you are building a freestanding deck and pergola the set out is the same, however be careful to refer to your deck and pergola span tables as additional support will be required.
Once you have your set out marked out and square, mark the position of your posts (refer to your pergola and deck span tables for the correct spacing) and dig the holes ready to concrete in your galvanised post supports. Concrete in the galvanised post stirrups.
Step two: Install the pergola and deck posts
Now install the common posts that will hold up both your deck and your pergola. This means that the post will need to be fairly long and you will need to brace them with timber to hold them in place. Make sure they are level and plumb.
Step three: Build your deck then your pergola
It easier to build your deck first and then use the deck to stand on, to build your pergola. The deck will also hold the pergola posts into position making it easier to construct your pergola. This means that you bolt the deck bearers to the posts and then bolt the pergola bears to the same posts.
Another option is to build the pergola at the height you want and simply add the deck under the pergola by bolting the deck bearers to the pergola posts. However you must refer to your deck and pergola span tables to make sure that spacing and timber size will be correct and strong enough.
For more on building a pergola see our page.
Adding a pergola to an existing deck
Most time you can bolt galvanised post stirrups to the existing deck bearers at the correct spacing for your pergola and then build a new pergola straight up from there. However you must make sure that your deck will be strong enough by referring to decking span tables. If you are in doubt then you must install longer posts that extend down through the deck and on to their own footings.
In most cases a pergola can be added on top of an existing deck as long as the deck is built properly.
