Rustic Arches and Pergolas
A pergola is a series of connecting arches that not only links areas of the garden, it also provides shade and support forand a very pleasing way of framing a view or aspect of your garden. Although you can construct a pergola from natural stone, brick, metal or wood, the rustic, wooden version is probably the commonest and the most cost-effective.
An arch or pergola made from rustic timber is relatively simple to construct and is sure to look good with climbing plants. Leave the bark on or use peeled wood: it doesn’t matter. If the bark is stripped there will be fewer hiding places for insects, however, and the wood is easier to work with. Rustic poles can be used to make an attractive support for climbing and rambling, as well as arches and pergolas. The same basic joints are used throughout.
A pergola must also be built to dimensions and designs that suit your garden, so plan it on paper first. Perspective is very important too, especially if your garden is on a slope, so get some friends or helpers to hold the poles in position before you start work. That way you can see from a number of different angles how well (or badly!) your pergola will fit in the setting you have chosen.
The easiest way to fix the horizontal poles to the uprights is to make a V-shaped notch in the top of each upright that will cradle snugly the horizontal pole. For a long pergola you will need to join the horizontal poles together. Make sure that all joints occur over an upright pole, to provide strong support. The top end of the horizontal pole sitting snugly in the notched upright should be cut into an L-shape. The adjoining horizontal pole that continues the line should also be cut into an opposing and matching L-shape, then you can nail them and the top of the upright together with rustproof nails.
Last but not least, the cross-poles should be notched and nailed over the horizontals, to complete the structure. For best effect, allow an overhang of about 15 cm (6 in) on all cross-poles and horizontals.
Once again you should sketch your design on paper before you set about sawing up your timbers. As before, get someone to hold the poles in position first, to give you a chance to see if you have the right height, design and perspective to suit your garden. Remember to allow about 60 cm (about 2 ft) extra on the uprights to sink into the ground.
It’s safest and easiest, once you are happy with the design and dimensions, to assemble and erect the sides first (see notes on joints below). When the sides are assembled, drive the uprights firmly into the ground, using a post rammer or a sledgehammer, carefully avoiding splitting the tops of the poles. Alternatively, insert the uprights in ready prepared holes and hold them in position with wooden struts, until they are fully secure in concrete or cement. Check the levels frequently to make sure your structure is at right-angles.
Next, assemble the top of the arch on the ground before attempting to fit it in position. When it is ready, lift it and drill and screw it into position, as nailing it is likely to leave you with too much movement on the structure as a whole.
You can have fun deciding on which basic joints to use, such as V-notches and opposing and matching L-shapes, to fix horizontals to uprights securely and attractively. If you have two crosspieces intersecting, join them with halving joints, using a saw and chisel to hollow out the joints.
Wood glue will certainly help to strengthen the joints but make sure at least that you nail each joint with rustproof nails.
If you want to be even more technical, you could use bird’s mouth joints to connect horizontal or diagonal pieces to uprights. Mark the position carefully, then cut out a V-shape about 2.5 cm (1 in) deep. Saw the joining piece to fit then drive a nail diagonally through the joint. Don’t worry if you don’t get the joints right first time – trial and error is inevitable!
CUT TIMBER PERGOLAS AND ARCHES
If your garden is neither ‘cottagey’ nor rustic in look and feel, you may prefer the cleaner, more modern lines of a prepared timber pergola or arch. The main difference, in terms of construction, is that there are fewer or no joints, as the horizontals or side rails and the cross-poles or rails are screwed and nailed in position.
As they provide the main support, the side rails are fixed securely to the face, not on top of the uprights, preferably with coach bolts or screws. Where the side rails meet there is no need to cut joints – simply butt the ends of the rails together and screw them to the post.
The cross-rails should be nailed diagonally down into the side rails.