CPD Specifier May 2015 issue January 2014 | Page 12
Roofs
Can’t see the advantage of this
Soffit Ventilator?
Good - that’s what’s intended
Introducing or upgrading the ventilation of an existing roof is commonly an
obligatory undertaking when the thermal insulation within the roof space is
increased. To provide air entry and exit opportunities ventilation apertures
are introduced through the soffit on opposing sides of the property. Once
established, air can flow into and out of the roof space (as long as the
insulation laid within it is restrained from blocking the flow route where the
converging roof timbers approach plate level).
After the soffit apertures have been drilled to provide 70mm holes, the
installer may choose whether the Type CSV Circular Soffit Ventilators are
fitted in a ‘see’ or ‘no see’ manner.
Type CSV ventilators have a
deflecting louvered face, providing
positive air entry and insect
screening. Rotating the Type CSV
so the louvers slope downwards
towards the property masonry
face when viewed from the ground
results in the ventilation openings
being almost hidden from
view. The soffit can maintain a
continuous unbroken appearance.
Alternatively, fitted with the louvers
facing the opposite direction –
outwardly - provides a punctuated
soffit appearance. The installer
has a choice. The Type CSV is
available in various colours and
has one of the highest airflow
ratings of 2,100 mm², which
means fewer need be installed to
provide the required performance
level.
To maintain an unobstructed
airflow path within the roof space,
Type REV (Refurbishment Eaves
Ventilators) work in conjunction
with the soffit ventilators. When
pushed into position, the Type
REV top section folds over to
follow the roof line. The moulded
flap shape maintains a void
against the underside of the
sloping roof underfelt, via which
air can flow unhindered. The roof
insulation is retained within the
folded section.
Reader Enquiry: 16
Together the Type CSV + REV
from Cavity Trays of Yeovil offer a
rarely seen advantage whenever