New Multi-Functional Cavity Barrier Stop
Water Deflection + Acoustic + Fire Integrity
There is a requirement for cavity
barriers / stops within timber frame construction and the minimum period of
fire resistance is commonly 30 minutes, even where the internal fire resistance
of the structure is greater. TRADA has drawn attention for barriers to be
sleeved in polythene dpc to ensure moisture is deflected away from the timber
frame structure and to the outside.
However, cavity stops are usually
rectangular and have a flat/horizontal upper surface, therefore even if sleeved
penetrating water can still use the upper surface as a bridge to track across
the cavity unless prevented from so doing. Thus it prompts a question of how
water will be deflected in the right direction by such sleeving, unless the
actual shape of the stop or an accompanying protective medium promotes such direction?
Currently stops are being
incorporated within cavities of buildings without deflection or protection
provision. Whilst the timber inner skin is surfaced with a membrane, to what
extent will that membrane remain serviceable in the long term if water collects
and pools against it?
Is the timber frame and its
membrane designed to have water pooling against it during the intended life of
the structure? In decades to come,
could such pooling against the inner leaf act as a catalyst and promote deterioration?
Such a construction detail is not
best practice.
The cavity barrier / stop must
deflect the water forward, and there is now a ready to use product that
automatically offers this + fire stopping + acoustic suppression.
Cavi
60 SAF Stop
Cavi 60 SAF Stop
is designed to provide acoustic, fire barrier and water-deflecting qualities
within a cavity wall.
The Cavi 60
prefix denotes 60 minutes fire integrity rating for this multi-purpose cavity
stop, whereas SAF is the acronym for sloping – acoustic – fire, the most
important qualities advanced by this product.
Non-combustible
rock wool is profiled and encapsulated within a polythene sleeve. The unique
sloping upper surface of the encapsulation deflects penetrating water forward
towards the outer leaf. The lower sloping surface permits lengths to be lapped
whilst maintaining deflecting, sound and fire integrity status.
The Cavi 60 Type SAF Stop is
compressible and may be friction fitted within the cavity, taking advantage of
placement upon naturally occurring ties to aid stability. Thus it is
incorporated without attachment to the inside or outside skin. Unlike
conventional stops that are rectangular and thus level between skins, the new
Cavi 60 Type SAF is sloping. It naturally deflects penetrating water forward,
thus promoting best practice at all times. A hard finish protective upper
surface cap is also available.
This new design offering twice
the minimum fire protection period plus acoustic suppression plus a water deflecting
shape is a product of Cavity Trays Ltd.
Cavity Trays Ltd is the only
cavity tray manufacturer awarded European Technical Approval.