The plywood must be:

a) no less than 17.5mm thick for roof areas and 20mm thick for deck areas
b) CCA treated H3.2 grade. LOSP-treated (light organic solvent preservative) or CuN treated (copper nitrate) plywood should not be used.
c) A minimum standard of ply is C-D. The C grade upper face should be sanded and plugged.
d) Panels shall be tightly butted together and laid with staggered joints (brick bond)
e) Plywood shall be laid with the face grain at right angles to the supports
f) The maximum span of supporting structure should be 400 mm centers for beams and nogs
g) The edge of sheets shall be supported with dwangs or framing - tough and groove plywood is not a substitute for this.
h) A 20 mm triangular fillet shall be used at the base of any 90° upstand and any sharp edges must be arrised
i) Plywood must be fixed
* using a suitable glue adhesive and,
* with countersunk head, grade 316, 10g x 50-60 mm stainless steel screws at 150 mm centres on edges and 200 mm centres in the body of the sheets.

What are the Minimum Drainage Falls for NURAPLY 3P?

BRANZ have appraised the Nuraply system to comply with the Building Code with a minimum fall for a roof of 1:40 and 1:60 for decks and gutters.

Be aware that individual Councils (Auckland City for example) may require falls in excess of this standard.

Consult with our technical advisors if your exceptional circumstances require falls less than this or if you have any issues getting your plans consented.

What is the installed weight of NURAPLY 3P per square metre?

3.5 kg /m²

What about using NURAPLY in high wind zones?

No problem, when installed properly. NURAPLY has performed in typhoon and hurricane zones for many years, from Taiwan to Vanuatu.

Is Roof-Space ventilation necessary?

If using a cool roof system then yes. Ventilation of timber roof spaces, particularly skillion roofs, has always beenrecommended by Nuralite Waterproofing Ltd. We recommend you use low profile Nuravents for this purpose.

In a warm roof situation ventilation is unnecessary as the insulation is designed to encapsulate the entire roof system.

What causes vapour bubbles under membrane roofs?

Vapour comes mainly from trapped moisture. NURAVENTS and Soffit Vents help avoid the problem, as does the NURAPLY 3PV ventilating system, our spot-fixed membrane specially developed for concrete surfaces which allows even greater vapour mobility.

What are the finish options for NURAPLY 3P?

Standard finishes are NURACOLOUR, in any colour, and NURACOAT in silver, both smooth mould-retarding surfaces.

NURAPLY 3PM is pre-finished with a choice of charcoal, slate, white, red or green granules.

Otherwise, NURAPLY 3P can be overlaid with tiles, concrete, asphalt, gardens or timber decking, and by using NURAPADS and paving tiles.

What Warranties apply?

The standard NURAPLY 3P material performance warranty is for 20 years. The product applicator will provide a separate workmanship warrantee. Customers should ensure they receive both of these from their applicator at the completion of the job.

What will be the future maintenance needs?

Periodic Inspections
A periodic inspection program should be established by the building owner. The inspection should concentrate on “high risk” areas such as hatches, drains and around all roof top equipment, as well as a general inspection of the entire roof. Inspections should also include the examination of the roof deck if possible from the underside for evidence of leaks, deteriorated decking, structural cracks or movement and other deficiencies. Parapets and edging should also be examined for evidence of cracking, deterioration and moisture infiltration.

Cleaning, Maintenance and Repair
Location, traffic level, effective drainage, and service use will dictate maintenance requirement.

Once a year the roof should be swept clean and washed down with a hose and broom, not waterblasted.

Particular attention should be paid to areas where ponding water is present. Ponding water causes dirt buildup and can lead to the premature breakdown of the Nuracolour coating system.

As with any coating system, new coats of Nuracolour will be required during the life of the Nuraply 3P system. Depending on environmental factors and the quality of the roof maintenance programme the coating will need recoating between every 5 and 10 years.

Redressing the NURACOLOUR Gel surface requires cleaning, followed by a new application of NURACOLOUR. This restoration is quick and inexpensive.

For damage repair the NURALITE Applicator uses NURAPLY 3P component products and special techniques to achieve neat, unobtrusive reinstatement of the NURAPLY 3P.

Can we collect drinking water from a NURAPLY system roof?

NURAPLY 3P with NURACOLOUR dressing is fine for this purpose.

We do suggest a third coat of Nuracolour is applied at installation and insist that the roof is well maintained during its lifetime.

For drinking water collection the roof needs to be be flushed with 2 or more heavy rain showers before water is collected. Slight bubbling of surfactants on the surface of the roof during these initial rain showers is normal and expected.

In accordance with Health Department guidelines, we recommend installing a first flush diverter to the downpipe so that only clean water is collected. This is particularly relevant when dealing with flat roofs as there is the risk of stagnant water occuring in areas of ponding.

Are Nuralite systems independently verified?

Yes, BRANZ has provided an independent verification of the Nuraply 3P system. The Joyce Group has reviewed the Nuradeck system. Both reports concluded that the respective systems meet or exceed the requirements of the Building Code.

What can I do to renew my old Nuralite roof?

Nuralite roof systems have a long life expectancy. However, at some point it is worthwhile considering tiding it up with a coating system or "rebirthing" it by laying a fresh membrane system over the existing one.

The document "Nuralite Sheet Membrane & Nuraply 80 - Care, Maintenance & Rebirthing" (PDF 589KB) tells you everything you need to know.

Contact Nuralite if you would like a representative to come and discuss your options.

How many layers should I specify?

Over the past few years, most customers have preferred to have two layers of Nuraply installed.

On plywood the revised Nuraply BRANZ appraisal covers double layer systems only.

We therefore recommend that specifications should be for double layers only.