Roofing materials for school buildings
Resources, advice and guidelines for choosing, installing and working with roofing materials.
|Level of compliance||Main audience||Other|
When your school is getting a new building, replacing a roof or reviewing the safety of your existing roofs, as a board you need to consider a range of factors that will help you choose the most suitable type of roofing material. Roofing must also be correctly installed.
- Choosing roof materials
- Installing roofs
- Supporting roof safety
- Translucent plastic sheeting used in schools
- Further information
Your project manager or designer should guide you on the best roofing material when you're getting a new building or replacing a roof, and you can seek advice from your property advisor when reviewing your existing roof safety.
In choosing roofing materials, you should consider:
- how the roofing will stand up to local weather conditions
- how it can keep energy costs down
- which components may have shorter lifespans (e.g. plastic materials that may become brittle or degrade)
- if it's suitable for your school’s location, for example, if your school is close to the sea, the roofing should be able to resist sea spray corrosion
- if it matches the building’s design and type of construction
- if it can improve the building’s appearance
- if its cost will be within the project budget.
Reducing risks in earthquakes
Light roofing materials reduce the risk:
- to life in a major earthquake
- of damage to the building in a moderate earthquake.
The Ministry’s policy is that heavy tile roofs must be replaced with lighter materials when upgrading buildings.
Roofing must be correctly installed. For example, the roof must:
- have the recommended roof structure
- be at the right pitch
- restrict accidental access to non-trafficable areas.
If it's not installed correctly, the manufacturer’s guarantees may be invalid.
Weathertightness and durability design
Find out about our design requirements for roofing materials and installation in our Weathertightness Design Requirements for new school buildings.
There has been recent attention placed on roof safety in schools. This is now a priority 1 area for property spending. Unless specifically designed for, school roofs are to be considered non-trafficable areas and access should be restricted at all times, with the exception of authorised personnel.
Roof glazing and clerestory (vertical windows on roofs) glazing can be constructed in various forms and materials that include domed roof lights, translucent roofing and safety glass to allow for natural light to illuminate internal spaces and external walkways. All these sky lighting features are required to meet relevant building legislation at the time of installation.
Designing or replacing a roof
Schools are advised to warn of the risks of accessing roofs and to prohibit access to only those with appropriate health and safety safeguards. Single storey buildings, particularly with low-pitched roofs are easier to access. Wide eaves can be a useful design approach to deter easy access to roofs.
Reviewing current roof safety
As far as practicable, schools are advised to prevent accessible routes to roofs and warn on the risks. Where possible decisions should be taken to separate ancillary buildings and structures (e.g. playgrounds) from school buildings to prevent staircasing on to other roofs. Schools should check whether fire escapes from roofs are still active, and if no longer required, consider blocking access or complete removal.
It is advised that all schools should take note of any translucent roof items (sheet, dome, hatch or other element) and visually check their condition for signs of deterioration. Contact your property adviser if there are any concerns.
Translucent plastic sheeting is a material often used in school roofs and verandas. It includes PVC, fibreglass and polycarbonate roofing products. However, you must treat this sheeting as a potential danger because of the risks that:
- people may fall through it — a risk that increases as the sheeting ages and becomes brittle
- it may catch fire as it can be flammable.
It's good practice to take measures to stop people from climbing on the sheeting. For ex ample, don’t have any structures close by that can be easily climbed.
Installing translucent plastic sheeting
To manage the risks of installing plastic sheeting, we have some specific installation requirements which you must follow.
Make sure your suppliers and installers are aware of them. As new products enter the market, suppliers, installers or project managers may suggest some of the measures below are not necessary. Talk to your property advisor about getting an exemption.
Fire Group Classification
The Building Code requirements for internal surface finishes are given as Group Numbers (Clause 3.4(a) of the Code). This may be known as ‘Fire Group Classification’. It represents the measure of how much smoke a material gives off when it burns. It's important that products used inside don't exceed these limits because the amount of smoke affects how easily people can escape. There are no Fire Group Classification requirements for products used outside because the smoke can disperse.
Learn more about Achieving NZBC Group Numbers for surface finishes from tests to overseas standards.
|Safety netting or mesh||
Some translucent sheet materials are classified as ‘trafficable’. When using these products, safety netting is not required. (Netting can be unsightly, deteriorates if unwashed and may be distorted through vandalism.)
To qualify as trafficable the material must:
If the sheets are non-trafficable, they must be laid over netting or mesh. The netting or mesh must be:
|Roofs, covered walkways and verandas||Exterior application
Translucent sheets are often used on open-sided structures on the exterior of buildings (verandahs) or between buildings (covered walkways).
For exterior application, where the translucent sheeting is:
Translucent sheets used within buildings and directly exposed to the interior spaces (including walkways or verandahs with side-walls, ie where smoke can accumulate) have the following requirements:
|Rules for walls||When installing translucent plastic sheeting to walls, position the sheets at least 2 metres above external ground level, or 2 metres above internal floor levels, whichever is higher.|
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