Constructing a pergola on an existing deck can greatly enhance your outdoor living space. The process of building a pergola on a deck versus directly on the ground has significant differences. The main obstacle to overcome when it comes to building a pergola on an existing deck is the fact that instead of anchoring the pergola to the ground, you are anchoring it to the deck. The main concern is instability because you aren't able to bury the posts into the ground. However, there are ways to build a pergola on your existing deck with sacrificing stability and safety.
Use Post Bases
Your pergola will have four support posts that must be anchored to the deck. Post bases will be used to accomplish this feat. These are the main support structures of the pergola. The post bases you use will be visible, so when choosing, look for visual aesthetics as well as functionality. It is important to note that when building on an existing deck, all hardware you use will be visible to family, friends, and guests. Choose decorative hardware that matches the rest of the landscape and the exterior of the home.
The Right Hardware
Attaching wood to wood requires specific hardware to ensure longevity, strength, and stability of your pergola. The hardware you choose should be made of thick steel and hot dipped galvanized in order to withstand even the harshest outdoor elements. Lag bolts are necessary when constructing the top frame of the pergola. As with the post bases, it is advisable to choose decorative bolts and hardware.
Incorporate Lateral Bracing
As we mentioned above, stability is one of the main concerns of pergolas constructed on existing decks. The reason is that pergolas are top heavy which makes them susceptible to high winds. Lateral bracing on your pergola is a must to prevent swaying, uplifting, and other structural damage to the pergola, deck, nearby structures, and people.
Use Pressure-Treated Wood
For maximum protection, it is advisable to use pressure-treated wood on the entire pergola. However, it is crucial to use pressure-treated wood for all of the support posts and beams. Untreated wood is susceptible to insect infestation and rotting which ultimately leads to weakening of the wood and compromises the structural integrity of your pergola. This can lead to a dangerous situation and a safety hazard. Pressure-treated wood is meant to resist insects, rotting, and to withstand harsh outdoor elements.
Be Mindful of the Pergola's Weight
It is an inherent feature of a pergola to be top-heavy. There's no way around this. With that being said, be mindful that the top of your pergola isn't too heavy for the support posts. Pay attention to load ratings and plan accordingly.
Before beginning construction on your pergola, refer to your state's laws as it pertains to pergola permits and building codes. The last thing you want to happen is to build your pergola only to find that it was not authorized or that some part of it does not come up to code. Each state has its own laws governing regulations on outdoor structures.
Enhance Your Outdoor Space
The installation of a pergola offers the benefit of enhancing your outdoor space by offering shade during the warm summer months, adding to the attractiveness of your landscape, and even increasing the value of your home as a whole in the event that you decide to place your home on the market down the road. Worthington Millwork offers a line of pergola systems with a variety of sizes, designs, and features to meet your needs. Contact Worthington Millwork today to learn more about their custom pergola systems!