It's not enough to design a roof that doesn't leak - you also have to plan its safe repair and maintenance. Barbour ABI and Scott Brownrigg offer a five-point guide on how to do it
All roofs must be designed and specified with maintenance and repair in mind. Despite this being a requirement of the CDM Regulations, it is an area that is often overlooked. Specifiers must ensure a roof is easy to maintain, and is safe for maintenance and repair workers. The specifier must plan how workers will access the roof and hand over this anticipated access regime to the building's occupiers.
A careful analysis of the roof and the access requirements must be undertaken. This should be presented as a risk analysis and give the actions needed on the roof, how frequently and what equipment is necessary. The specifier should identify all the equipment needed and ensure that it is supplied complete with additional items such as specialist clothing.
It is a commonly held view that many roofs can be constructed and forgotten as long as they don't leak. This is a shortsighted perspective as even the most resilient roofs require inspection and, as a bare minimum, the cleaning of their drainage system. Roof maintenance should be planned and budgeted for, as roof leaks are potentially the most costly and disruptive of all building failures. Heading off problems before they advance too far will pay for itself in the long run.
If the gutter system is simple and located at the perimeter, mechanical access can be used to inspect and clean it. At the same time the roof can be jet-washed and generally checked. This will avoid the need for further access, except for any inspections required by the roof system guarantee. In this case, specialist safety access can be employed such as temporary guarding to the whole roof.
2 The inspection regime
Planned access is the best way to ensure a roof will enjoy the longest life possible. Good practice should consist of a monthly inspection for the first year and once every three months thereafter. Once every three years a full survey and maintenance inspection should be carried out and every 10 years a thermographic survey should be carried out to check insulation performance.
Commonly used materials should provide years of trouble-free service, single-ply roofing 25-30 years, built-up felt at least 20 years and metal standing-seam roofing 50 years or more.
The Working at Height Regulations 2005 require a safe working environment at all times so careful consideration must be given to roof access points. The ideal route is from a main stair that continues to a door at roof level. Warning of the roof environment beyond the door must be given and, as an absolute minimum, complete guarding for the direct area outside the door should be provided.
Remember, limited access may also be required for roof plant and machinery. Plant requiring regular access needs special consideration; it should be given a dedicated means of access and this must be clearly designated. Occasional access still needs to be designed and specified as an integral part of the roof.
4 Guarding systems
Guarding from the roof access point to the plant should be continuous and preferably in accordance with BS EN 5395-3:1985 or better. The designer may decide to guard the whole roof and some would say this is the only truly safe option. However, sometimes this is not achievable and with high performance roofs with little or no plant this may be an over-provision.
If access to the general area beyond the guarding is required, a safety harness system should be considered. This should be designed in consultation with a specialist. It should at all times prevent access to the edge of the roof. This is because of concerns over fall-arrest systems. It is now clear that fall arrest can have serious consequences and, unless a sophisticated harness and management protocol is in place, it can be lethal. Only fall prevention can be specified with some confidence. However, installing any system can have its drawbacks.
If access to the roof can only be through a ladder or steep companionway stair to a hatch, ensure that the edge of the hatch is guarded. The open side should have a gate or at least chains. The access ladder should have an extended handrail at the top ensuring that as the hatch is opened the operator always has a safe handhold. Clear instructions and warning notices should be placed at the base of any access ladder. It is crucial to ensure that there is no unauthorised access.
All these provisions should also apply where near-continual access is needed, except that greater care needs to be taken to prevent casual access. Ensure that railings are not climbable and safety advice is clearly positioned. Any additional equipment must be stored near to hand.
5 Watch points
To sum up, make sure that all the following points have been considered when you design the roof and its maintenance regime.
- Design the roof access from the outset.
- Set out the timing, type and requirements of future inspections.
- Inspections should be recorded and include photographs.
- Do not specify fall arrest systems.
- Ensure that guarding and safety systems are practical and will work.
- Make sure the client understands that inspections may be needed to comply with the roof system warranty.
Subject guides similar to this are available from Barbour ABI as part of its Construction Expert and Specification services. For further information contact Barbour ABI on 01344-899280