38 | AUGUST 2019
Installer Support
Installer Support is
sponsored by Kayflow
THE TOP TO BOTTOM OF ROOFLINE
A trade-focussed guide to solving repair and maintenance issues at the roofline.
Dave Osborne of roofline
specialists Swish, takes a look at
the roofline – the hard-to reach
part of a building where the roof
meets the walls - and looks at
some of the important Dos and
Don’ts of roofline repair and main-
tenance.
Most problems at the roofline
start with rot. We live in a damp
climate and timber fascias, soffits
and bargeboards – what the in-
dustry calls roofline products – all
suffer badly and need replacing
if they don’t see regular mainte-
nance.
Here, we’re going to look at best
practice at the roofline. Some dos
and don’ts that will remove the
need for future repair and main-
tenance customer and ensure a
good standard of workmanship for
your customer.
First of all – choose the right
material for the job. Softwood
used to be king but cellular PVC
is now the best choice at the
roofline. It won’t rot, it doesn’t
need painting, you don’t need
special tools to fit and it costs
roughly the same as timber. What’s
more, it will last the lifetime of the
building.
So, if you’re faced with soffit and
fascia replacement and the old tim-
bers are past their best, what’s the
best way to tackle the job?
1. Cut back and replace.
There’s no point in covering old
timbers if the are decayed. First
of all, remove or push back a
couple of rows of roof tiles to get
a good look at the front and back
of the fascia and the rafters. If
they’ve seen better days, it’s better
to replace. Only cap or cover if
you are 100% sure of the existing
substrate.
2. Cut back rotten or degraded
felt as it will serve no purpose if
it doesn’t dress into the gutter.
This can be replaced with an
eaves protection system - a rigid
PVC profile designed to be fixed
on top of the fascia and rafters to
bridge the gap left by cutting away
the rotten felt. It also dresses into
the gutter and will not degrade
with exposure to rain wind or
sun. Alternatively, use a new PVC
membrane.
3. Cut back any rotten rafter
ends to sound material and
splice in new sections. Make
sure new timber feet or packers
are set to line and level – a simple
string line will do - as any small
deviation will show once the
fascia is fitted.
4. Always use the correct fix-
ings for the new boarding. For
cellular PVC boards up to 9mm
thick, use 2 x 40mm A4 stainless
steel, ring-shanked Trimtop nails.
For boards thicker than 9mm, use
2 x 65mm A4 stainless steel ring-
shanked Trimtop nails. Centres
should be @ 600mm for white
boarding and 400mm for foiled
and coloured boarding.
5. Never butt boards together
– always leave a 4-5mm expan-
sion/contraction joint per board
end. Cover these with PVC joint
or corner trims.
6. Don’t superglue or pin
both sides of the PVC joint trim
to the boards. This would pre-
vent any expansion/contraction
movement and could split the
trim. Silicone one side and super-
glue the other or pin one side out
of sight above the gutter line until
the silicone cures.
7. Provide adequate ventila-
tion for new roofs – it’s a must
for Building Regulations and it’s
worth adding ventilation, ei-
ther via the soffit, pre-vented or
inserted ventilators or over-fascia
ventilators [OFV] to minimise
visibility and to bring older roofs
up to current standards.
8. Always make box ends
from a single, large piece of
profile, cut to suit, rather than
jointing fillets of boards and
risking water ingress. It looks
better and it works better – Job
done.
Dave Osborne is Technical
Manager for Cellular PVC roofline
specialists Swish Building Prod-
ucts. For more detailed guidance,
we also recommend readers to
refer to Industry Code of Practice
available from The British Plastics
Federation [www.bpf.co.uk]
For more information:
Swish Building Products:
01827 317 200
www.swishbp.co.uk
2. Cut back and replace rotted rafter
ends and splice in new sections. Always
cut back and replace degraded felt.
1. When timbers are past their best,
what’s the best way to tackle the job?
3. It’s best to use a string-line
as any small deviation will show
once the new fascia is fitted.
4. Make sure you use the right
fixings and spacing for the job.
5. Here’s what a model
roofline structure looks like.
And here’s what a good finished job
looks like when you do it the Swish-way.