You might have a lovely big deck or pergola with lots of plants around, a nice
entertaining area, sun filtering through the pergola - a perfect place for a
Just like the deck in Lets Do It, however it has no cover so if it rains it spoils
the party. If you have the same problem what you can do is put some roof
sheeting on the pergola.
Translucent sheeting is good for a number of reasons. It is light, so you donít
have to worry about whether the type of structure you have will carry it, and it
is clear enough to let plenty of light in.
To prepare the pergola Monte needs to put some battens in because there arenít
quite enough cross members to support the sheeting.
He will also have to make sure the sheeting is tight up against the facia board
to make sure the water doesnít collect and drip through.
The good thing about the pergola is that it already has an inbuilt pitch and the
water will run from the top to the bottom. If you havenít got a pitch you will
have to remedy that before you get started.
If you want the battens to sit flush with the top of the beams they need to be
rebated in. This will allow you to put your sheeting over the top without any
Decide at what width you want to keep your battens apart. 900mm is a recommended
for this type of sheeting. Use a chalk line to mark the beams in a straight
Measure 900mm on two of the beams and make a mark. Line up your chalk line along
those marks and mark all joists in between with a clear line. That line is the
bottom side of the batten. Line up the batten to mark the other side with a
A small cordless saw is the perfect tool for cutting the rebates into the joist;
it is light and has no cord that could get in the way. Set the depth on the saw
to the thickness of the batten so that the battens will sit flush with the top
of the beams.
Make a cut along each marked line on the joist and a few extra cuts in between
to allow you to chisel out the rebate. Once you have made all your cuts use a
chisel to remove the waste. The batten should then sit nice and flush in the
rebate and you can nail it down.
On many pergolas you will be able to nail the battens straight on top of the
joints but Monte had to rebate the battens in to fit the roof sheet under the
houseís little barge capping.
Once all your battens are in place you will be ready to lay down the
polycarbonate sheeting and screw it down, but before you do that you might want
to paint the battens to match the rest of the pergola.
There are a number of different types of polycarbonate sheeting on the market;
one of the best is called Evercool from Alsonite.
The surface that points down has a shiny aluminium foil finish that reflects UV
rays and heat away from the area. The other side has strips running along the
surface that let light through. These will provide your area underneath with
nice soft natural light throughout.
To secure the sheeting to your timber structure you will need roof screws. They
are long enough and they have ceiling washers with a profile specifically cut to
fit over the corrugation in the sheet. You need a bit on your drill to fit the
But first you need to pre-drill the holes through the sheet with a fairly large
bit. You want quite a large hole to allow for some expansion and contraction in
Remember to drill through the corrugation not through the flat section.
Although the sheets are light they can be a bit awkward to work with and of
course you canít walk on them once they are up. Therefore, if you need to cut
them to size, make sure you do all measuring and cutting on the ground
To cut the sheets use a 100mm angle grinder or a circular saw fitted with a
diamond blade. Be careful to mark a straight line across the profile of the
surface to ensure you end up with a straight cut. Clean up any rough edges with
Screw the sheets on one at a time except for the overlapping edge which you
canít screw down until you have put the next sheet down.
The sheeting is very light, so if you are doing this job on a windy day you
might need some help holding the sheeting down as you fix it to the structure.
If you use self drilling screws you can screw them straight into the timber
Donít forget to set your cordless drillís clutch to a low setting to avoid
tightening down the screws too much, otherwise they will distort the roof
sheeting and pull it out of shape.
The manufacturerís instructions will specify whether you need to screw down
every rib. With the Evercool product from Alconite you can skip every second
rib, except when you come to the ends, where you need to screw down each one.
The last thing you need to do is run a bead of Selleys All Clear
along where the
sheets butt-up against the bargeboard. It will stop any drips in case there is a
deluge of rain.
Every roof is different. If you are lucky, yours might be straight and you can
order all your sheets cut to length.
But even if yours requires a lot of cutting, it is definitely worth it because
you end up with a beautiful all-weather outdoor space!