Pergolas add a stunning focal point to gardens, provide shade in the summer months, and create a sheltered spot from which to enjoy your garden in fall.
As with all home improvements, safety is paramount, so ensuring your pergola is secure is essential. Since they are usually stand alone structures, it’s important that they can support their own weight and withstand inclement weather.
This is where providing the right kind of anchor comes in – and securing your pergola with concrete is one of the best ways to do so.
Do You Need to Anchor a Pergola to Concrete?
As pergolas do not have a base of their own, it is essential to make sure they are properly footed.
Traditionally, this has meant setting the pergola’s pillars directly into a concrete pillar, but, as engineering processes have been refined and wood engineering has been improved, this is no longer always the best option.
We weigh up the pros and cons of the four most common methods of anchoring your pergola below. Additionally, you can also anchor your pergola to pavers.
Posts Inserted Directly into a Concrete Pillar
This has been the go-to method for anchoring pergolas for home builders for a long time. It provides solid, permanent support for your pillars but it is really difficult to get right. Due to the nature of wet concrete, ensuring your supports are truly plum is very challenging as they are prone to shifting while the concrete is curing.
Also, it has been shown that your wooden pillars will absorb just as much water in concrete as they would if sunk directly into the ground but as the concrete is immovable, as the wood shrinks over time, your pillars will begin to show signs of movement over the years, causing your pergola to wobble.
Posts Inserted Directly into the Ground
With modern engineered wood, this method is proven to be just as effective as anchoring your pillars into concrete. The drawback here is that this method requires a huge amount of wood.
In order to ensure your pillars are stable, you will need to sink a third of your wood below ground. For example, for a 7 foot pergola, you will need pillars at least 10 feet long, to allow 3 feet to be anchored in the ground.
This method is also incredibly labor intensive and can be back-breaking work to carry out.
Post Brackets and Post Supports Using Stakes and Braces
If your pergola is going to be attached to your house, or another strong structure, surface mounted post brackets can provide enough support to hold up the free standing end. This method is not strong enough for a completely free standing structure.
Concrete Mounting Kit
Concrete mounting kits are engineered to provide secure, long lasting support for pergolas. They keep the wood away from the ground and use concrete footers to provide sturdy, long lasting support for your pergola.
How to Anchor a Pergola to Concrete
We walk you through a step-by-step process of how to use a concrete mounting kit below.
Step 1: Preparing Your Base
Drill a 6 inch deep hole into your footer using a masonry drill bit and remove all of the concrete dust from your hole to make sure the epoxy can form a proper bond.
Be sure to check that you haven’t drilled all the way through your footer (this prevents the epoxy from seeping out). If you have drilled all the way through, you can add some sand to the bottom of the hole to seal any gaps.
Step 2: Fixing Your Supports
Next, you will need to add your epoxy by inserting the nozzle as deep into the hole as you can and slowly drawing it upwards as you fill the hole with epoxy.
While the epoxy is still wet, insert a threaded rod into the epoxy, turning it as you go. Turning the rod will ensure the epoxy flows into the threads, forming a good secure bond as it hardens. Be sure to keep your threaded rod straight as you insert it to prevent difficulties later in the installation process.
Remove any epoxy from around the hole once your threaded rod is inserted. You should have around 12 inches of threaded rod visible above the surface once it’s fully inserted into your base.
Step 3: Leveling
While waiting for the epoxy to harden (cure), install the leveling studs and nuts into the holes on the column leveling plate. Use one nut on the top and one on the bottom for each stud. These nuts will allow you to adjust the levels of your bases, making sure your pergola sits squarely on its concrete base.
When your epoxy has cured according to the manufacturer’s instructions, place a leveling plate onto each rod. Use the leveling nuts and a laser or spirit level to ensure each leveling plate is level.
Once each plate is level, use a couple of wrenches to ensure each stud is secure and add a nut and washer to the rod and secure it in place. Then, screw your now level plate into the concrete base using the guide holes.
Finally, add a hex nut and the coupler to the top of your threaded rod and tighten.
Step 4: Assembling Your Pergola
Once you’re ready to put your pergola up, square the bottom of your pergola columns, add the base trim to the bottom of your column and place your column onto the base trim.
Insert the long threaded rod inside your column and secure it tightly to the coupler. Add the rest of your columns according to the instructions received with your pergola kit, securing each section as you go.
Following these steps will ensure your pergola is sturdy, safe and pleasing to the eye.
Mistakes to Avoid, Tips & Tricks
Lastly, to make sure things go well with your project, keep the below in mind:
- Do not skimp on footings for your pergola
- Ensure your footings, anchors and supports are level at every step of the process
- Don’t be fooled into thinking that a concrete base will keep your pergola stronger than sinking it into the earth
- Do your research and choose the correct footing for your particular project
Summary
Concrete pillars aren’t always the best option and modern engineered wood almost completely does away with the need for them. Using a combination of concrete footings and epoxy with a concrete mounting kit is often the most simple and strongest anchor for your pergola. It is certainly less labor-intensive than other methods.
By following our advice to choose the correct anchors for your pergola, you will have a long-lasting, beautifully square structure that is as strong as it is beautiful, allowing you to enjoy your pergola for years to come.