Derbigum Roofing Membranes are fibreglass/polyester composite reinforced, modified bitumen torch on membranes for roofs.
- Abbreviation
- Appraisal number 923
- Amendment
- 02/05/2016
- Valid from
- 29/04/2016
- Information provider
- BRANZ Limited
- Information type
- BRANZ Appraisal
- Format
Description
Derbigum Roofing Membranes are fully bonded, double layer torch on systems for use on roofs,
gutters and parapets. There are five membranes available. They are used where an impervious waterproof membrane is required to prevent damage to building elements and adjoining areas. The products can be used on new or existing buildings.
Scope
Derbigum Roofing Membranes have been appraised as roof waterproofing membranes on buildings within the following scope:
- the scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1; or,
- the scope of limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1 with regards to building height and floor plan area when subject to specific structural design; and,
- with substrates of plywood or suspended concrete slab; and,
- with minimum falls for roofs of 1:30; and,
- situated in NZS 3604 Wind Zones, up to, and including Extra High.
Derbigum Roofing Membranes have also been appraised as roof waterproofing membranes on buildings within the following scope:
- subject to specific structural and weathertightness design and,
- with substrates of plywood or suspended concrete slab; and,
- situated in specific design wind pressures up to a maximum design differential ultimate limit state (ULS) of 6 kPa; and,
- with the weathertightness design of junctions for each specific structure being the responsibility of the building designer.
Roofs waterproofed with Derbigum Roofing Membranes must be designed and constructed in accordance with the following limitations:
- nominally flat or pitched roofs constructed to drain water to gutters and drainage outlets complying with the NZBC; and,
- with no integral roof gardens.