Clearview National September 2019 - Issue 214 | Page 48

SOLIDROOFTECHNOLOGIES
A CONVERSATION ABOUT CONDENSATION
There are a lot of lightweight
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 contains 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 significant enough
the dew point will be reached and form
condensation that can eventually turn to
mould and spread.
To make sure your selected solid 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 supplied 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 material 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 specification
includes vapour control barriers on the
room side
• Check that the roof has successfully been
through a CRA (Condensation Risk
Analysis)
48 » SE P 2019 » CL EARVI E W- UK . C O M
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 insulation. 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 condensation issues.
I PREFER TO BUILD MY
OWN IN TIMBER, THE FINAL
PRODUCT IS THE SAME
Experienced joiners will certainly 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 lightweight
• 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 looking to add
value to the property or need Building
Control approval.
• The houseowner is not looking for the
best performing roof or the prettiest
finish
• The insulated roof does not exceed the
original weight it was designed for.
• You know what you are doing, because
a collapsed roof / conservatory is not
something that want to come up on your
portfolio.
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 of site. Our tiles our delivered to site
with the roof for ease. Of course our pods and
other components are carefully labelled for a
worry free installation.
www.icotherm.co.uk