Repair, Refurb, Retrofit
Damp Level Thresholds?
Isolate the problem
In excess of 70% of damp problems associated with level thresholds
originate through a failure to correctly interface converging protective
elements. A recent investigation suggests the three most common failures
occur for the following reasons:
1.
Incorrect integration of the vertical closing arrangement at
threshold level.
2.
Failure to adequately incorporate isolation measures where the
floor construction unites with inner and outer masonry skins.
3.
Where the Type LTT meets the reveal masonry either side of the opening
it continues upwardly and around both faces of the reveal, wrapping the
masonry skin and extending into the actual cavity. Any reveal cavicloser
simply projects downwardly between the protective wraps at each end of
the tray. The standard horizontal DPC in both skins can safely terminate at
any course level within each protective wrap - regardless of the threshold
level.
Insufficient oversite membrane is available to turn up all wall/
reveal faces after being stretched around the 90° internal skin
corner projecting into the room. Consequently the membrane is
usually cut to accommodate the projection and a weakness
results adjacent to the reveal face.
The Type LTT by Cavity Trays of Yeovil promotes a standardised route
to damp-free level thresholds. By isolating the masonry most susceptible
to damp transference, the Type LTT permits abutting flooring, abutting
insulation, horizontal DPC’s and oversite membranes to safely integrate.
The flooring arrangement may continue over an inside skin and converge
with an exterior skin that itself is isolated from dampness at the point of
convergence.
The Type LTT requires no further work once fitted to the inside skin and
is undetectable when works are complete. When fitted to the outside
skin, the Type LTT may be trimmed back externally to suit the frame
position upon completion of work, so it is not readily visible. When used
with Caviclosers from the range offered by Cavity Trays Ltd, the specifier
benefits assured compatibility and an accompanying performance
warranty.
The Type LTT (Level Threshold Tray) by Cavity Trays of Yeovil offers a
standardised approach designed to overcome such inadequancies.
The Type LTT is a ready-shaped DPC specifically designed for use on
both inner and outer masonry skins at threshold level. The Type LTT
acts as an isolation DPC ‘glove’ enveloping and covering the top and the
sides of the threshold masonry. Once in place, flooring arrangements
can interface with the skins at threshold level without danger of wet
transference.
CAVITY TRAYS
TEL: 01935 474769
WWW.CAVITYTRAYS.CO.UK
READER ENQUIRY NO: 39
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