The falls outlined in our CodeMark certificate must be accepted by Council provided the membrane is being installed in accordance with our Installation Manual.
The CodeMark falls are:
|Substrate||Plywood||Concrete||Existing Substrates||Concrete with Tapered Boards or Flat Enertherm
|Plywood with Enertherm
|NPM900 or approved metal tray (B) with Enertherm
|Minimum Finished (Constructed) Falls||1:80||1:80||1:80||1:80||1:80||1:80|
|Recommended Design Fall (excluding gutters) (A)||1:40||1:60||1:60 Confirm no ponding areas||1:60||1:40||1:40|
|Substrate Comments||Using 17mm (roofs) or 21mm (decks) plywood, rafters at 600 centers, nogs at 600 centers.||Create required slope with a screed. Wait for concrete and screed to cure.||Confirm substrate is sound.||*Minimum fall available using tapered boards is 1:60. Nuralite can assist with tapered board layout.||Create required slope in the plywood.||Create required slope in the NPM900.|
The fall is most commonly expressed as a ratio, such as 1 in 80, or as an angle, although it is sometimes convenient to describe it in terms of a percentage slope where by definition 1 in 100 is 1%. This is convenient for calculation as it expresses the fall in centimetres per metre run.
The relationship between falls, angles and percentage slope is indicated below:
|Fall ratio||Slope angle||% Slope||Rise in mm over 1m|
|1 : 120||0.5°||0.8%||8|
|1 : 100||0.6°||1.0%||10|
|1 : 80||0.7°||1.3%||13|
|1 : 60||1.0°||1.7%||17|
|1 : 40||1.4°||2.5%||25|
|1 : 38.2||1.5°||2.6%||26|
|1 : 28.6||2.0°||3.5%||35|
|1 : 19.1||3.0°||5.2%||52|
|1 : 14.3||4.0°||7.0%||70|
|1 : 11.4||5.0°||8.7%||87|
The plywood must be:
No less than 17mm thick for roof areas and 21mm thick for deck areas.
CCA treated H3.2 grade. Do not use LOSP-treated (light organic solvent preservative) or CuN treated (copper nitrate) plywood.
A minimum standard of ply is C-D. The C grade upper face should be sanded and plugged.
Panels shall be tightly butted together and laid with staggered joints (brick bond).
Plywood shall be laid with the face grain at right angles to the supports.
The maximum span of supporting structure should be 600mm centers for beams and nogs.
The edge of sheets shall be supported with dwangs or framing - tough and groove plywood is not a substitute for this.
A 20mm triangular fillet shall be used at the base of any 90° upstand and any sharp edges must be arrised
Plywood must be fixed:
using a suitable glue adhesive and;
No problem when installed properly. Nuraply has performed in typhoon and hurricane zones such as Taiwan and Vanuatu for many years. On request Nuralite can confirm wind uplift designs for specific projects.
In a Nuratherm warm roof situation ventilation is unnecessary as the insulation is designed to encapsulate the entire roof system.
If using a cool roof system then yes cross flow ventilation is required. Ventilation of timber roof spaces, particularly skillion roofs, has always been recommended by Nuralite to assist with removal of interstitial moisture and mitigate high temperatures in the ceiling cavity.
The method for creating cross flow ventilation is a design consideration. A practical and unobtrusive way is using soffit vents. Alternatively we supply a purpose designed Nuravent which is installed on the roof itself.
Nuraply 3PM, 3PG, 3PC and 3PT/PTM have CodeMark certification, the highest certification possible in New Zealand.
The CodeMark must be consented by Councils if specified in accordance with the Nuralite install manuals.
BRANZ has provided an independent verification of the Nuraply 3PM, Nuraply Everguard TPO and Nuratherm systems as well. All reports have concluded that the respective systems meet or exceed the requirements of the Building Code.
The standard Nuraply 3PM material performance warranty is for 20 years. The product applicator will provide a separate workmanship warranty. Customers should ensure they receive both of these from their applicator at the completion of the job.
The building owner should establish a periodic inspection programme. 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.
It is a warranty requirement that the roof has a full inspection by an approved applicator every five years. This should provide peace of mind that the system is performing well.
Cleaning, Maintenance and Repair
Nuraply 3PM membranes have been independently tested to meet NZ standards for potable water collection. For Nuraply 3PM a glaze coating is recommended, which will require replacement during the life of the building.
Nuraply Everguard TPO, being a smooth thermoplastic membrane, is well suited for potable water collection throughout its useful life.
Greenroofs are not suitable for collecting potable water because little water gets through the soil substrate and what does may be containated by fertilisers.
In accordance with Health Department guidelines, on all roofs where water is collected we recommend installing a filter and using a first flush diverter, so that only clean water is collected.
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.
We also strongly recommend considering insulation at this point. Nuratherm can be installed over the existing membrane to bring the entire roof system up to modern standards.
The document tells you everything you need to know. Contact Nuralite if you would like a representative to come and discuss your options.
648 KB | Updated: March 2019
Around 9kg /m2 for a double layer system.