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How to make a lean-to pergola

How to make a lean-to pergola

Simple, yet eye-catching, a well-made pergola can really transform the look of your garden and add a touch of traditional European, without it looking out of place.

The beauty of lean-to pergolas lies in their simplicity. Made from a collection of supports and cross beams, there are no super-tricky carpentry methods needed to build one and two people with basic DIY skills can throw one up in no time.

Now, we realise that not everyone is as confident with hammers, drills, and saws as we are, and if you would rather buy a ready-made pergola or kit, you should take a look at our best pergolas reviewed page.

For the more adventurous of you, this article will explain what a lean-to pergola is, what it isn’t, and most importantly- how to make one yourself.

The internet is full of posts by people who have made their own pergolas just like this one below, so by not join the club?

What is a pergola and lean-to pergola?

As already mentioned, a pergola is an open structure, usually consisting of wooden beams, although there are metal pergolas on sale these days, and in ancient times they would have had stone pillars.

It is possible to put a roof on a pergola, but they are normally left without a completely closed roof. Some people choose to grow vines or similar on their pergolas for decoration, like on a trellis, but most just leave them as an open wooden structure.

Lean-to pergolas get their name from the fact that they are only supported by beams on one side, with the other side being connected to another structure like the outer wall of your house. This makes them easier to construct and provides them with a lot of support at the same time.

if you’re interested, this video explains what a pergola is and shows examples-

What is a lean-to pergola used for?

I’d be lying if I said that that the main purpose for pergolas isn’t decorative, but they do provide extra shade to the area beneath the structure, especially when fitted with a retractable sunshade.

However, those looking for more shade might prefer a sun shade sail. Unlike lean-to pergolas, sun shade sails are not permanent structures and can be disassembled quickly and packed away for winter.

These guys hung shades down on theirs and it looks very efective-

Things sometimes mistook for pergolas

Pergolas are often mistaken for other garden structures, such as arbours and gazebos, but there are some differences that we’d like to point out here.

Arbours are smaller structures than pergolas, and they are not really meant to be used as a cover to place your garden furniture beneath. Instead, they are more suited to acting as archways over garden paths and can be an amazing way of separating one area of the garden from another.

Gazebos (wooden structures, not pop-up ones) differ from pergolas in that they have fixed, solid roofs that can be quite decorative and found in various shapes and designs. They are usually larger structures than pergolas, and often feature raised floors too. If you’re looking for some creative ideas when it comes to gazebos, take a look at this-

How to make a lean-to pergola- step by step

Here we will walk you through the steps necessary to make a lean-to pergola of your very own. It is a fairly straightforward process, and we have kept the design, tools needed, and instructions for this DIY project as simple as possible, but if you are confident enough, feel free to add some decorative elements of your own.

1. Know what the parts of the pergola are called

Before we start, I think it’s a good idea to know the names of the individual parts of a pergola, so that you’ll know what I’m referring to in the instructions. The main parts are the posts, the header boards, the purlins, and the supports. When I talk about posts, I am strictly referring to the main vertical pieces that will be connected to the ground and bear most of the weight of the pergola. Header boards are the pieces of timber that connect to the tops of the posts and run horizontally across the whole length of the pergola. The header boards will have notches cut into them for the purlins (roof rafters) to slot into.

2. Measure the area and draw up a plan

Everyone’s lean-to pergola will be slightly different sizes due to the available space, and dimensions and design of their house, and for this reason, I haven’t included any specific measurements in the instructions as it will just get confusing. What you need to do is go outside and take your own measurements. You’ll need to work out and write down how tall you want the overall structure to be, how long, and how wide. If you are planting the posts into the soil rather than hard surfaces, account for the extra inches you’ll need that will be sub-surface.

Once you have these basic measurements written down, you should think about how wide apart you want your main posts and purlins to be, as this will give you an accurate number of them to cut. Don’t forget to allow for the thickness of the timber in your measurements, and I don’t mean these measurements 😂-

3. Choose, cut, and prepare your timber

The type of wood that you choose will all depend on how much you are willing to spend on your project, but for the British climate, I would suggest using red cedar or European green oak.

Once you’ve decided on your wood, you need to cut it to the measurements that you worked out earlier. Having said that, we do have some tips on the thickness of the timber-

For your main posts, we recommend using 6×6 or 4×4 as they will give extra strength and support to your pergola. You can use either 2×8” or 2×10” pieces for the header boards and 2×6” for the purlins.

If you look at the image below, you can see a very simple pergola that I helped my friend build a while back. As you can see, the ends of the purlins and header boards have been shaped with a mitre saw for decoration, but it is perfectly fine to leave them with flat ends if you don’t have the tools or skills necessary.

You will also see that the purlins sit in notches that have been cut in the header boards, so you will need to work out how far apart to cut these notches and how deep. This is where your plans from earlier come in very handy.

You can choose to cut the timber yourself, using a circular saw, jigsaw or mitre saw, but it is probably easier getting it done for you at a timber yard or DIY shop. After the wood is cut make sure you treat it with wood-stain or similar.

4. Prepare the ground

If you are planning on planting the posts into the soil, you will need a post hole digger or earth auger to make the required holes, and some cement to hold the posts in place later. For securing the posts on a hard surface like a patio, the best things to use are metal post supports. These can be fixed into the ground with screws and a hammer drill.

5. Fix the posts to one of the header boards

The best way to achieve this first part is to work on the ground. Make sure you’re on a flat surface, mark out where the posts need to go and use a drill to make pilot holes in the header board before bolting the posts to it. Then fix some small support beams coming down from the headers to the posts at 45-degree angles. These are more for decoration than anything, but they will add a little structural support too.

6. Secure the rear header board

As this is a lean-to pergola, you’re going to secure the second header board to the wall of your house. Before that though, you’re going to need something to hold the back end of the purlins in place, and if you look at the photo below, you’ll see how we used metal joist brackets for this purpose. With the brackets attached to the correct places, you can then bolt the header to the wall.

7. Lift the structure

Now, with some help, lift the posts and front header that you fixed together earlier and place them into the metal post supports, or the holes you dug earlier. If it’s the holes you are going with, you’ll need some way to hold the posts in place while you pour cement in there and wait for it to set.

8. Finish off your lean-to pergola

All that’s left to do now is to slot the purlins into place and secure them with screws, and you should be now looking at a simple, but nonetheless attractive lean-to pergola. it should also be strong enough for you to string up a hammock if you so wish, and will provide some good shade for your garden furniture.
You an also pop your BBQ under there like this-

As we already mentioned, feel free to add any decorative elements and changes that you like, this is only a very basic design and construction method aimed at giving anyone a chance at building their own lean-to pergola.

Once built, you should keep an eye on the structure and give it an extra coat of stain or paint from time to time to keep it looking its best. As you can see from the photo of my friend’s pergola, he has let that slide recently and it is looking a little worn, but with regular maintenance, yours should last you for years.