Appraisal number: 768 (2012)
Date issued: 1 Aug 2012
Hitchins Reinforced Bitumen Roofing and Deck Membrane Systems
Hitchins Reinforced Bitumen Membrane Systems are for nominally flat, pitched and curved roofs, decks, gutters and parapets. They are installed as a torch-on, two-layer system with a top layer finished with mineral chip or plain and coated. They can also be installed as single-layer systems onto concrete substrates with either a top layer finished with mineral chip or plain and coated or with traffic protection such as paving slabs or topping screed. The products are reinforced, APP, SBS and SBS/APP polymer-modified bitumen sheet in roll form.
Hitchins Reinforced Bitumen Membrane Systems have been appraised for use as waterproofing membranes for buildings within the following scope:
- The scope limitations of NZBC Acceptable Solution E2/AS1 paragraph 1.1.
- With timber supporting structures designed and constructed in accordance with the NZBC.
- With nominally flat or pitched roofs constructed to drain water to gutters and drain outlets complying with NZBC.
- With substrates of plywood sheet.
- With decks that have a maximum size of 40 m².
- Situated in NZS 3604 wind zones up to and including extra high.
Hitchins Reinforced Bitumen Membrane Systems have also been appraised for use as waterproofing membranes for external reinforced concrete and plywood roofs, pedestrian decks and balconies for buildings within the following scope:
- Up to 3 storeys with a maximum height from ground to eaves of 10 m and with a floor plan area limited only by seismic and structural control joints.
- With the reinforced concrete structure designed and constructed in accordance with the NZBC.,
- With timber and steel supporting structures designed and constructed in accordance with the NZBC.
- Subject to maximum ultimate limit state (ULS) wind pressures of 4 kPa.
- With nominally flat, curved or pitched roofs constructed to drain water to gutters and drain outlets complying with the NZBC.
This Appraisal is limited to roofs, decks and balconies within the following scope:
- Constructed to suitable falls.
- With no steps within the deck level, no integral roof gardens and no downpipe discharging directly onto the deck.
The design and construction of the substrate and movement and control joints is specific to each building and therefore the responsibility of the building designer and building contractor and is outside the scope of this Appraisal.
The membranes must be installed by Hitchins New Zealand Ltd licensed and trained installers.
Hitchins Torch On Bitumen Membranes Application Manual, June 2012
Always refer to the Appraisal in full and the technical literature.