Protected Membrane Roofs Offer Flexibility and Efficiency

Commercial building owners are increasingly looking to balance building construction costs with long term energy-efficient and ecologically friendly design features.

Features such as green roofs and warm roofs, while frequently specified, are often excluded from final designs during the consent process. This is because architects are specifying traditional roofing membranes that are not designed or suitable for the application they are being used in, and New Zealand has been traditionally slow in taking up new technology and building practices that are common overseas. An example of this is the Protected Membrane Roof (PMR).

When it comes to low sloped roofs there are two basic systems, the membrane can be exposed or it can be protected. Most roofs in New Zealand are exposed membrane roofs, and while in some applications this is perfectly acceptable (or even a better solution), there are many cases where a PMR roof is a far better solution.

A good example of this is the ASB North Wharf building. Jasmax approached Allco Waterproofing to provide a specification, and it quickly became apparent that the client had very high expectations around energy efficiency and durability. After looking at traditional solutions, it was decided that the best solution for the project was a PMR roof with ILD (International Leak Detection).

Some of the advantages that a PMR roof has over a traditional membrane roof include:

Long term cost savings
Longer time between tear offs
0° pitch roofs (Hydrotech only)
Efficiency during construction
Greater design flexibility
Protection from trades (eg. HVAC)
Protection form wind uplift and UV
The membrane can also be ILD or flood-tested before insulating and ballasting
Can easily transition between stone ballast, pavers and green roof

Allco Waterproofing has a number of PMR solutions to suit every application including the world renown Hydrotech Monolithic Membrane.

View the video above 'Protected Membrane Roof (PMR): An Innovative Solution for Michigan State University' or watch it on youtube.

Casali Torch On

Allco Waterproofing Solutions

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Casali is an Italian torch-on roofing membrane made of pure bitumen with the highest quality techno-polymers.

Casali Roof and Deck Membrane Systems have been appraised as roof and deck waterproofing membranes on buildings within the following scope:

the scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1; or,
the scope limitations of NZBC Acceptable Solution E2/AS1, Paragraph 1.1 with regard to building height and floor plan area when subject to specific structural design; and,
with substrates of plywood, fibre cement compressed sheet or suspended concrete slab; and,
with minimum falls for plywood roofs of 1:30, concrete roofs of 1:60 and decks of 1:40; and,
with deck size limited to 40m² and,
situated in NZS 3604 Wind Zones up to, and including, Extra High.
situated in specific design wind pressures up to a maximum design differential Ultimate Limit
State (ULS) of 6 kPa with the weathertightness detailing subject to specific design.

Casali Roof and Deck Membrane Systems have also been appraised for use as roof and deck waterproofing membranes on specifically designed buildings within the following scope:

With building structures designed and constructed to comply with the NZBC; and,
With roof and deck supporting structures of timber framing with substrates of plywood or fibre cement sheet; and,
With substrates of suspended concrete slab; and,
Subjected to maximum wind pressures; and,
With the weathertightness design of all junctions being the subject of specific design by the designer.

In the opinion of BRANZ, Casali Dermabit/Dermafil Roof and Deck Membrane Systems, if designed, used, installed and maintained in accordance with the statements and conditions of this Appraisal, will meet or contribute to meeting the following provisions of the NZBC:

Clause B2 DURABILITY: Performance B2.3.1 (b) 15 years and B2.3.2. Casali Dermabit/Dermafil Roof and Deck Membrane Systems meet this requirement. See Paragraph 10.1.
Clause E2 EXTERNAL MOISTURE: Performance E2.3.1 and E2.3.2. Casali Dermabit/Dermafil Roof and Deck Membrane Systems meets these requirements. See Paragraphs 13.1–13.9.
Clause F2 HAZARDOUS BUILDING MATERIALS: Performance F2.3.1. Casali Dermabit/Dermafil Roof and Deck Membrane Systems meet this requirement.

Casali Dermabit/Dermafil Roof and Deck Membrane Systems have been appraised as an Alternative Solution in terms of New Zealand Building Code compliance. The membranes are an alternative to the membranes specified in NZBC Acceptable Solution E2/AS1, and an Alternative Solution subject to specific design for other buildings not covered within E2/AS1.

BRANZ Appraised

Hydrotech Monolithic Membrane

Allco Waterproofing Solutions

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Hydrotech Monolithic Membrane 6125 (MM6125) is a thick, tough, flexible, self-healing membrane for use in roofing applications.

1. Hydrotech (MM6125) membrane system has been assessed as a waterproofing membrane solution for use in cold roof and deck assemblies, and Protected membrane roof and deck (PMR) assemblies.

2. The system must always be protected as follows:

a) On PMR assembly: one of the following overlays must be installed over the insulation layer
- Pavers or floating timber deck on pedestals
- Ballast (graded stones)
- Green roof
- Concrete topping slab
b) On a trafficable cold roof/deck assembly: one of the overlays described in 2(a) must be used:
c) On a non-trafficable cold roof/deck assembly or where only maintenance related traffic is expected: the membrane must be protected with a layer of Hydroflex 30 or Casali Olympia.

Pavers or floating timber deck on pedestals
Ballast (graded stones)
Green roof
Concrete topping slab

3. The system will resist the effects of wind uplift likely to occur in practice. The effect of wind on the overlays described in 2(a) falls outside the scope of this certificate.

4. The system may be used on buildings within the following scope:

a) On new buildings or existing buildings in all exposure zones, excluding microclimates, as defined by NZS3604: 2011.
b) On reinforced concrete substrates with any pitch including zero pitch defined as less than 1:100/0.5, gutter fall must be maintained at a minimum of 1:100/0.5

See CodeMark certificate for full information.

If designed, used, installed and maintained in accordance technical literature and manufacturer's instructions Hydrotech Membrane (MM6125) System will comply with or contribute to comply with the following provisions of the NZBC:

Clause B1 STRUCTURE: Performance B1.3.1, B1.3.2, B1.3.3 (b), (c), (f), (g), (h), (m), (n), (q), B1.3.4 (b), (c), (d), (e)
Clause B2 DURABILITY: Performance B2.3.1 (a) where ballast, green roof or concrete topping slab are used and B2.3.1 (b) where not, B2.3.2 (b)
Clause E2 EXTERNAL MOISTURE: Performance E2.3.1, E2.3.2, E2.3.7 (b), (c)
Clause F2 HAZARDOUS BUILDING MATERIALS: Performance F2.3.1

See CodeMark certificate for full information.

CodeMark

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