What is a Cavity Cup?
The Cavity Cup is a moulded ABS plastic device that encompasses plumbing fittings and protects the insulation cavity of an exterior wall from any potential leaks. These leasks may occur from either water ingression through poorly sealed penetrations in the building wrap, or hardware failure of the plumbing fittings at the penetration point. The Cavity Cup has been designed to be used in conjunction with fittings that meet the AS/NZS, and should be used wherever a penetration through the insulation cavity occurs.
How does it work?
The Cavity Cup is fitted into place so that the edge of the flange finishes flush with the wall framing. The plumbing fitting is fixed and connected so it is inside the Cavity Cup and the flow of water comes through the top.
A hole is removed from the building wrap to match the cup and it is then flashed around the flange so that the top overlaps the bottom. Finally, flashing tape is applied over the Cavity cup and building wrap.
The Cavity Cup contains and discharges any water that enters the insulation cavity from the penetration in the building wrap or from hardware failure at this point. The water is discharged out of the font of the flange and down the face of the building wrap allowing the air flow through the cavity to evaporate the water.
Why is it important to seal penetrations through building wrap?
Incorrectly sealed penetrations through building wrap are a major cause of the leaky homes syndrome. Water that has leaked between exterior linings will ingress through poorly sealed penetrations and allow water into the insulation cavity. This will deteriorate the framing and structure of a building and promote the growth of a black mould (Stachybotrys or Chaetomium). These moulds have been linked to skin and respiratory diseases.
Meets and exceeds NZBC regulations
The Cavity Cup meets and exceeds the following clauses from the NZBC:
• B2-DURABILITY-REF B2.3.2
• E2-EXTERNAL MOISTURE-REF E2.3.2
• E3-INTERNAL MOISTURE-REF E3.3.6
• F2-HAZARDOUS BUILDING MATERIALS-REF F2.3.1
The Cavity Cup is warranted for a period of 50 years from the date of purchase.