Build it Yourself: Wooden Pergola

In most parts of the world, pergolas are used to cast much-needed during the afternoon, sheltering man and beast from the relentless midday sun.

Here at home, things tend to be a bit different. In Scotland, pergolas spend most of their lives sheltering people from the relentless drizzle!

Unfortunately, pergolas won’t actually shelter you from the rain. The big gaps between the rafters see to that.

Nonetheless, pergolas are lovely additions to any garden and provide definition to an outdoor space without constraining. When the weather does break and the blue skies emerge overheard, pergolas provide a lovely blend of inside and out. While this is similar to deck, pergolas offer a space more entwined – both literally and figuratively – with nature

This blog will teach you how to safely erect a simple pergola. After that you are only limited by your imagination.

 

What You’ll Need

• Wooden posts – 85mm x 85mm x 3m
• Wooden cross piece – 33mm x 33mm x 1.8m
• Wooden beam – 45mm x 95mm x 3m
• Stainless steel screws
• Bolts
• Cement

 

Preparation

Your first big consideration is the siting of your pergola. We recommend choosing an area with a buffer of at least 50cm on all sides. Ideally you want a bit more to provide a good cushion of free space but some gardens are tight and this can’t always be found.

Next think about the sun. Firstly, you’ll need a lot of sun to keep your vines and climbing plants healthy. Secondly, you’ll want a lot of exposure because that’s what pergolas are for. They are designed to let you lounge about in the middle of summer, keeping you cool and comfortable. There’s simply no point in building one already in the shade.

Finally, think about the view from indoors. A pergola is a reasonably big wooden structure so even when it’s covered in plants, it’s not exactly subtle. Mark out possible locations and inspect them from all onlooking windows in your house. Ask yourself whether siting your pergola in a particular place will spoil or complement the view.

When you’ve chosen a piece of ground, clear all existing vegetation from the area. Then that’s the preparation done – you’re good to start building.

 

Construction

Dig holes for your four corner posts. These should be about 30cm square and 60cm deep. After you’ve dug down to the required depth drop a post into the hole.

When you’ve got two posts next to each other erected, lay a cross piece on top and use a spirit level to check whether they’re level. If one is slightly lower, infill its hole slightly and check again. This step is a little finicky but it’s worth spending a bit of extra time now to get your pergola square. Work round your post holes until all uprights are up and level.

Secure each post using scrap timber so they can stand on their own.

Mix a firm concrete using only enough water to just bind the mixture together. Pour the concrete into the post holes and compact it with a length of wood. Since the mix is quite stiff, it’s useful to have a spare pair of hands to keep each post steady as you pour in the concrete. Use a plumb line to make sure each post is straight.

Repeat for all other uprights and leave the concrete to set.

Join the cross beams to the uprights using halving joints. Use a mallet to encourage the timbers together and bolt them together to keep them secure.

Finally, fix the wooden beams to the cross beams to form the roof. We recommend you cut notches into the each beam’s bottom edge to allow them to straddle the cross timbers. Fix the timbers in place using structural screws.

Finishing Touches

Although pergolas are attractive structures on their own, a bare one is like a empty plant pot.

Plant ramblers and strongly-growing climbing roses to give body to your pergola and watch as the timber skeleton bulks out. Clematis and honeysuckles a couple of other excellent choices.

For more information, check out the Royal Horticultural Society’s excellent article on planting pergolas.

Finally, some people like to fix trellis panels to the sides to their pergola to create a little extra privacy and protection from the wind. To do this simply affix premade lattice panels onto the main uprights.

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