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Build a Pergola
We'll start with a pergola because you can keep them
as plain and simple as you like or if you're feeling brave you can get a
bit more technical and include some added features.
In this example we'll build the pergola 10 ft long, 6
ft wide and 8ft high.
Mark out where your 4 support posts will be. These
posts will be 4X4. We always use metal
post spikes for fixing as they
prevent timber rot by protecting the bottom of the posts. Knock your
first spike in until the post will sit just above ground level. If you
are building a large pergola you can always dig out around the post
spike and add some concrete for support.
Using this first spike we measure off to determine the
exact position of the others. Measure 6ft across for your width and 8ft
for your length. Once the spots are marked, measure corner to corner to
make sure you are square and adjust if necessary.
Once you are happy you can knock in the remaining 3
spikes with your sledge hammer. Use a straight edge and a level running
from spike to spike and check they are all reasonably level. Temporarily
place the posts in the spikes and check the tops of the posts are all
level with each other with your straight edge and level. It doesn't need
to be absolutely bang on, just reasonable.
Now you have a few choices regards the tops of your
posts. The easiest way is to bolt the cross beams to the sides of your
posts but you can, if you want, cut the top of the posts to seat the
beams in one of the 2 ways as shown in the drawing.
Your 2 beams are 6x2 but to make sure the cuts are the
correct size, hold the beam against the post to mark out the cuts. Mark
the top of the posts and return the mark down the sides. Cut down to the
desired depth. The first diagram method will require a chisel to remove
the unwanted wood once you have made the 2 saw cuts.
If you are simply bolting your beams to the sides,
drill the holes in all 4 of the posts but only drill the hole in one end
of each beam. Remember when marking for drilling that the posts will be
eight ft apart but your beams are 10ft to give a foot over hang at each
end.
Whichever method you have chosen, once the top of your
posts are prepared you can fix them in place by putting them in the
spikes and screwing with galvanized screws. Use your level to try and
keep them plumb when fixing. There may be a little play in them but
don't worry as they will be fixed in position as the beams and roof go
on.
If you want you can trim the ends of the beams into
a shape by cutting at an angle.
Once the posts are in place you can put one of the
beams up. Fix one end with a couple of 3" galvanized screws. Before
fixing the other end get someone to plumb both posts with a level. you
will be plumbing the edges facing each other. If any adjustment is
required you can make it by moving the beam away or towards you. Once
its good enough, fix the other end and repeat the process for the other
beam.
If you are bolting to the side, fix the side you
drilled and while holding the other end against the post, adjust until
both posts are plum to each other. Once you are happy, mark, drill and
fix with 2 carriage bolts.
We'll use 8ft long, 4x2 timber for each of the end
roof rafters so we again have a foot overhang either side.
Again you can cut the ends at an angle to form a
shape. Find the center of your rafters by
measuring the full length and dividing by 2. Mark the center with a
pencil.
Make sure the posts are plumb on the edges facing each
other. Measure the distance from the inside of one beam to the other and
divide by 2. Assuming the measurement is 8ft, measure 4ft either side of
your center mark on the rafter and mark again. Measure the thickness of
your beam and again mark. Measure 2" down the
face and mark. Saw down to the 2" mark and using a chisel, knock out and
clean. Sit the rafter down onto the beam over
the top of the posts and using an hammer tap down until the beam is all
the way into the 2 slots in your rafter. Repeat for the other end and
fix by screwing down from the top with galvanized 3" screws.
Your pergola is now ready for the roof. You could repeat
the process you used for the
rafters by adding more 4x2 at equal gaps or simply screw some 2x2 at
equal gaps. If you are hoping to create a roof
of vines use 2x2 criss-crossed either at right angles or diagonally to
give the vines plenty to get hold of. Add some
finishing touches such as the corner braces or perhaps a trellis to one
of the sides. |