What it cost
Making a polytunnel boat tent
on each end. The track was fitted by
simply screwing it to the underside of
the beams.
The curtains we decided to use were a
little tall for our needs, so the rollers were
removed from the top and the curtains
shortened by 200mm, then the rollers
reattached. The curtains were fed onto
the tracks with the buckles on the inside,
the first one going across the front and
partway down the side. The second one
was cut to fit the remaining side. The third
one went across the back and partway
down the other side, with a final one
finishing the side to the front corner. Once
all of the curtains were in place a hole
was drilled in the side of each track, at
the ends, and a small bolt put in place
to stop the curtains from coming off.
We needed to hold the bottom of the
curtains down, and fortunately had just
replaced the guardwires on the boat so
we were able to recycle the old wires for
this purpose. We attached the wires to
the base of the scaffolding poles all
around the frame, using an additional two
eyes across the ends cemented into the
ground where there weren’t any poles.
Once all the wires were in place they
were tensioned with bottlescrews in two
of the corners. The curtains still had the
buckles attached, and they hooked
underneath the wires and were fastened.
At the ends, the eyes had rings attached,
and we squashed these slightly so that
they would fit into the buckles.
To finish securing the curtains where
they overlapped, we used short bungee
cords. We attached eyelets to the bottom
of the curtains and hooked the bungees
to them. At the top, we hooked the cords
to the roller frame on the adjacent strap.The polytunnel in use
All in all, the polytunnel boat tent has
worked well, and the curtains are great.
We only need to open up a corner for
access in the winter, but in the summer
we can open both ends and the sides to
help keep it cool. The covers for the ends
went up easily when they were needed
and, with a bit of sun, it gets warm
enough inside even in the middle of
winter to allow us to carry on working.
There have been a couple of issues
with the top cover that, with a little more
knowledge of polytunnels, could have
been avoided. Firstly, polytunnel frames
get hot in the sun, and this can cause a
deterioration of the cover. A foam tape,
called anti-hotspot tape, is applied to the
tubes to insulate them from the cover.
Our frame had most of its anti-hotspot
tape still in place, but unbeknownst to us
the covering layer had come off, and it is
this thin film which prevents a reaction
taking place between the foam and the
covering sheet. We discovered this on a
wet autumn day when we noticed some
drops of water on a couple of the frames:Polytunnel frame £100
Scaffolding tube £100
Tarpaulin sheets £170
Timber for the side/end beams £50
Track for the curtain sides £200
Other bits and pieces £50
TOTAL £6 70We already had some items, for example the scaffolding
joints, but even with everything added in the whole
structure has cost us less than £700. To my mind it has
been well worth it for the comfort it has provided when it
has been pouring with rain outside and throughout the
cold weather. We were able to work throughout the winter,
so our estimate of two years to complete the restoration
remains achievable.closer inspection revealed some small
holes in the sheet where it was in contact
with the tube. An internet search revealed
both the cause of the problem and the
solution – an anti-hotspot repair tape
that could be placed over the existing
anti-hotspot tape. The same supplier
also sold polytunnel repair tape in
various widths.
To make the repair, we loosened the
brackets on one side, allowing us to push
up the side beam and thereby slacken
the entire cover. This enabled us to first
fit the anti-hotspot repair tape and then
a strip of 50mm polytunnel repair tape
to the inside of the cover. We also cut
some 150mm strips from the remaining
bit of cover we had left and fitted these
between the hoops and cover. On the
outside, we applied a strip of 75mm
repair tape over the area it had been
leaking from. The repairs have been
fine throughout the winter, and the
supply of repair tape has been useful
for a few minor repairs.
The second issue we have had is
condensation on the inside of the top
cover. We didn’t have any problems until
we put the end covers up, in the middle
of October. A few weeks later we opened
up as usual and got dripped on: the
inside of the top was covered in water
droplets. We have alleviated the problem
by fixing a second lightweight polythene
sheet on the inside with a small gap
between this and the outer sheet: this
catches the drips and directs them
down the edge of the tent away from
the boat and us.
The only thing I might consider
changing is the top sheet. The one
we’ve used is fine, and with a little TLC
and some repair tape should see us
through to the end of the restoration
of the boat: but, as stated earlier, it is
200g/sq m. We have since found out
that the sheeting normally used on
commercial polytunnels is a lot heavier
at 700 to 800g/sq m and has a life
expectancy of five years.▲ To hold the
curtains down,
eyes were
cemented into
the ground▲ At the ends,
the eyes had
rings attached,
and these were
squashed slightly
so they would fit
into the buckles▲ We attached
eyelets to the
bottom of the
curtains and
hooked bungees
to them. At the
top, we hooked
the cords to the
roller frame on
the adjacent strap