How can a fire start in a roof space? Good question and it’s as simple as a few significant issues which can be avoided with an annual check of your roof space. Some causes are poorly insulated downlights; wiring installed or terminated incorrectly, rodent’s chewing wiring or pieces of asbestos based materials lying around.

Let’s start with what is the most common problem that we find when inspecting houses for property purchasers and that is halogen downlights. The Australian Wiring Rules stipulate a minimum clearance for halogen recessed downlights of 200mm between the downlight and structural members, thermal insulation and any other substance unless the luminaire has a suitable fire resistant enclosure.

The most common situation we find is insulation surrounding downlights. It seems that insulation installers don’t understand the dangers associated with placing insulation over downlights or within the 200mm clearance requirements. While the danger is not the insulation or downlight catching on fire, it’s the debris that comes in under the eaves that trap itself against the insulation and downlights that create the fire opportunity. Insulation will singe but not burn because it’s treated with a fire retardant, but it can create heat. We have seen many instances of singed insulation especially if it’s loose fill insulation as it will tend to blow around in the roof space with air movement and then position it self against the downlight.

Secondly, if someone places a cardboard surround around the downlight (not within 200mm), the light will generate enough heat to burn the cardboard (as shown in the below photo). Now if you throw in some leaves into the mix, and they are trapped in the cardboard surround you now have fuel and a reasonable chance that a fire could occur. While you may say this is unlikely and yes maybe your right but it can happen as it did to an owner-occupier in a Canberra property only a few years ago.

Figure 1: downlight with a burnt cardboard surround well within the 200mm required clearance

There are only three options when considering your downlights.

1. Fit an aftermarket halogen downlight guard. These are a cover or guard that is fire resistant and sits over the downlight and avoids debris or insulation coming in contact with the heat of the lights.These are quite expensive and hard to fit in a low access roof space
2. Buy fire rated halogen downlight hood kits which have the covers built in
3. Consider fittings that don’t use halogens and run cooler and reduce the risk of fire. Led downlights are now a replacement for halogen downlights, and they only require a 25mm clearance.

Wiring not correctly terminated or joined, or power points installed but not installed correctly is another hidden risk in a roof space. If wiring hasn’t been terminated correctly or is exposed and other trades enter the roof space, who are unaware of the risk, an electrocution may occur. The other risk in this situation is if a handyman or even a licensed electrician is prepared to carry out work in this manner what other shortcuts have occurred. Interestingly this instance and the above occurred on the same property, and we have a suspicion it was carried out by a Licensed Electrician.

Figure 2: Incorrectly terminated power point

Asbestos based material in a roof space. The photo below shows a piece of broken asbestos based material (needs to be tested to be confirmed) in a roof space. This property had an asbestos roof which has been replaced; however, broken pieces remain in the roof space. Unfortunately, this is also a common situation in a subfloor as a result of a renovation. It is a case of careless trades not protecting the occupants and future trades who may need to access these areas.

Figure 3: potentially asbestos based material

Last but not least, its that little pest called rodents who love to nibble on our wiring and expose a risk. You can see the bite marks on the wiring in the below photo which was attached to a transformer in the roof space. While this is unlikely to cause a fire if RCD’s are installed there remains a risk if these systems fail or you have an old fuse system installed. The other factor is the damage and the replacement cost of the wiring when the little critters nibble all the way through. So if you hear rodents in your roof or walls don’t ignore them engage a reputable pest manager and find where they are coming into the property and block them out, so it doesn’t become a regular occurrence. They tend to enter roof spaces in the winter looking for the warm comfort of home.

Figure 4: Damage caused by rodents

What do we recommend? Firstly if you are buying a home that you have it inspected by a highly respected building inspector who you know will crawl around in a roof space and not just flash a torch from a manhole to find these kind of problems that could potentially cause a fire risk. Secondly, have someone regularly, say every 12 months take a crawl or look around the roof space.

Bruce Cohen
Technical Director
Surety Property