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Non-Ventilation Cold Pitched Roofs (partially
supported)
Roofers Choice when installed as a partially supported system
should be
fixed in the traditional method for roof tile underlays laid
parallel to the eaves
and draped between the rafters to ensure that any moisture
reaching the
underlay will drain away. It is held in place by the tile
battens, fixed using staples
or large headed nails. Roofers Choice can also be installed
by pulling taut
from gable to gable provided that a 25mm counter batten is
fixed to each rafter.
Prevention of Condensation
The complete roof construction, ceiling boards, underlay,
insulation and roof
tiles should be considered as a total roof system with regard
to condensation
risk. Insulation at ceiling level should be pressed tightly
into the eaves against
the underlay and all penetrations into, and out of, the roof
space should be
sealed. More extensive details of this can be found in our
BBA certificate
Section5.
Prevention of Condensation (Extensions)
The roof space environment in both the extension and the
original part of the
dwelling should be the same. If the original part of the
roof is vented then the
extension should also be vented. Only if the extension is
completely sealed off from
the original roof should the VapR-free be installed without
the aid of roof space
ventilation.
Non-Ventilation Warm Pitched Roofs (fully supported)
Roofers Choice when fully supported by the insulation can
be laid vertically
or parallel to the eaves and held in place using counter
battens (minimum
height 25mm). These in conjunction with 25 mm tile battens
will ensure a
minimum 50 mm clear airway above the underlay and will assist
natural air
movement through the batten space. Battens should be fixed
using staples
or large headed nails.
Roof space ventilation is not required for warm or cold pitched
roofs
but ridge or high level ventilation over the roof underlay
for tight fitting tiles or
slates will assist any moisture vapour to disperse more easily
when air
temperatures are very low.
General
Roofers Choice must be installed with the (Grey) Printed
side, face-up and
overlapped with the minimum dimensions listed. Trimming is
achieved with a
sharp knife. When partially supported with a horizontal lap
between battens an
extra batten should be introduced 25mm above the bottom edge.
This will
restrain the lap from opening under wind uplift.
Roofers Choice prevents the ingress of wind driven rain and
can be used as
a temporary roof covering and left exposed to the elements.
However it must
be installed as recommended in our technical leaflet with
regards to overlaps,
fixings, draped between rafters or counter-battened and direct
contact with
uncured treated timber avoided. |
