14 | SEPTEMBER 2019
News
Installer News is
sponsored by FENSA
A CONVERSATION ABOUT CONDENSATION
There are a lot of light-
weight tiled roof iterations out
there, and beyond selecting a
product for price there are several
points that you should question
when you are selecting the system
you want to work with.
Will my selected roof be
prone to condensation?
Definitely not something you
want to be dealing with 12 or
even 24 months following the
installation.
If there is one thing that cannot
be avoided, it is that our air con-
tains moisture. In the UK, average
relative humidity (moisture) levels
can be as high as 80%.
Not much of a problem on
the outside of windows, or even
on roof tiles. More of a problem
when this happens on the inside
of the roof and creates interstitial
condensation.
Interstitial condensation is
formed when cool moist air (read:
UK air) gets into the fabric of
the roof and hits warmer air, or
components that are warmer. If
the temperature change is signif-
icant enough the dew point will
be reached and form condensation
that can eventually turn to mould
and spread.
To make sure your selected sol-
id roof will not create interstitial
condensation:
• Check that there is a suitable
ventilation cavity to take out
the moist air out of the roof,
situated above the insulation
and on the cool side of the
roof
• Make sure the insulation sup-
plied is sufficient to minimise
any cold bridging and stop
warm air from reaching the
external rafter.
• If the system uses a cold
bridging aluminium frame:
ask if that metal is suitably
clad in non-conductive mate-
rial to limit the possibility of
condensation (more work and
more cost if you have to use
both aluminium and timber
though)
• Check that the design specifi-
cation includes vapour control
barriers on the room side
• Check that the roof has suc-
cessfully been through a CRA
(Condensation Risk Analysis)
Doesn’t ventilation
just mean draught?
A correctly ventilated solid roof
will allow air circulation where it
matters the most: well away from
the room it sits on top of, right
under the tiles and above the insu-
lation. Never be tempted to block
ventilation routes or vents; you
would invalidate your warranty
and end up having to retile the
roof to clear up potential conden-
sation issues.
Beams are cut to size, as is the
‘ insulation,
and we now offer a cut tile
service on Metrotile, which is saving
our customers a lot of time on site
’
I prefer to build my
own in timber, the final
product is the same
Experienced joiners will certain-
ly find it easy to build a suitable
timber frame, but the benefits of
buying a dedicated pre-built are
many:
• No cutting on site and wasted
timber or other components
• Ready to install kits
• Supplied with the insulation
and the tiles
• Kits are designed to be light-
weight
• The reputable roof systems
will have had their design
tested for structural integrity,
Condensation risk, making
it easier to obtain building
control approval. Look out for
LABC or JHAI certification
Why clad-overs
should be avoided
Some installers are probably
happy with carrying out clad-
overs, and as a low budget option
might have their place if:
• The houseowner is not look-
ing to add value to the prop-
erty or need Building Control
approval.
• The houseowner is not
looking for the best per-
forming roof or the prettiest
finish
• The insulated roof does not
exceed the original weight it
was designed for.
• You know what you are do-
ing, because a collapsed roof/
conservatory is not something
that want to come up on your
portfolio.
£5000 FOR CHILDREN’S CHARITY
VEKA UK Group presents cheque to Child Action North West
Industry-leading PVCu
profile manufacturer VEKA
UK Group has donated
£5000 to support children
across the North West.
Sue Cotton, CEO of CANW
said: “Every day brings new
challenges to the lives of
vulnerable children and
young people across the
North West. Thank you very
much to VEKA UK Group
and your employees for your
extremely generous dona-
tion. Your efforts will allow
us to help to strengthen and
support children and young
people to lead healthy and
meaningful lives. Every year
we work with around 7000
vulnerable children and
families across the region
providing a wide range of
services including counsel-
ling and school and family
support, help with educa-
tion and employment, early
help for young people in
trouble who are becoming
involved in offending and
finding foster families for
those children who can-
not live at home. We know
that children can achieve
amazing things given the
right support, thank you for
helping us do that.”
www.vekauk.com
The Icotherm roof system
The Icotherm roof system uses
a solid roof construction, with
150mm EPS fully recyclable, rigid
insulation, and is fully ventilated.
It has been CRA checked and is
JHAI certified.
Supplied in ready to “slide on”
pods, which can be made to suit
hard to access installation sites,
such as having to go through the
house (ie small pods), the Icoroof
allows you to fully retrofit a roof,
with all tiles installed in only eight
hours.
Beams are cut to size, as is the
insulation, and we now offer a cut
tile service on Metrotile, which is
saving our customers a lot of time
on site. Our tiles our delivered
to site with the roof for ease. Of
course our pods and other compo-
nents are carefully labelled for a
worry free installation.
www.icotherm.co.uk