Thatch fire protection

July 13, 2015

Fireproof Thatch Homes

One of the main issues with thatched roofs is the perceived additional likelihood of their being a fire in the property. It is true that if a fire takes hold in a thatched roof, the result can be more damaging than in a conventional property but we believe a well-managed home is a good risk for insurance purposes. There are a number of precautions you can take towards thatch fire protection to ensure a higher degree of safety in your property:

Ways to help with thatch fire protection

There are three main ways in which you can help to fireproof a thatched property, and if all of these methods are used together then maximum protection against the spread of fire will be achieved. It is advisable to take precautionary measures against the spread of fire as, although thatched homes are safe, the devastation caused by a fire will be much more widespread.

Thatch Insulation Batts

These are manufactured from a lightweight, semi rigid resin bonded mineral rock wool, are water repellent and easy to install. They are compression fitted between the roof joists and are supported by galvanised steel brackets that are fixed to the rafters. The high density and non- combustible properties of the batts reduce heat transfer around the roof timbers in the event of a fire and increase protection from fire on the underside of the thatched roof. An added advantage is that they also improve both the thermal and the acoustic insulation of the property.

In tests on two thatched houses, one containing thatch insulation batts, it was seen that these gave up to one hour extra fire protection to the underside of the thatch, reducing the spread of the flames.

Aluminium Barrier Foil

This is a fire resistant barrier and thermally reflective insulator that is made from heavy gauge aluminium foil. It is applied in the same way as roofing felt, and has the added benefit of providing a waterproof covering to the roof that is advantageous during the roof thatching process. When barrier foil is used alongside thatch insulation batts, the highest possible level of protection from the spread of fire is given.

Fire Retardant Sprays

Two types of fire retardant spray exist, one for use indoors and the other for use outdoors. The outdoor spray is applied directly on to the outer surface of the roof. As it is both water and fire repellent, it cannot be washed out. It must be sprayed upwards and into the thatch at an angle and not only onto the surface of the roof. The indoor spray is used on the internal surface of the thatch and on the supporting timbers. The internal spray does not need reapplication as long as the roof is maintained in good condition, whereas the outdoor spray usually needs reapplication every ten years (it should be tested to assess whether a respray is needed every five years).

There are various different makes of fire retardant spray on the market but they are generally a water based solution containing fire retardant chemicals in a polymer emulsion binder that is specifically manufactured for thatch. They are non- toxic, odourless, fast penetrating, fast drying and bio degradable.

Fire retardant spray should be applied by trained professionals using high pressure specialist equipment. Ideally the roof should have had two hours of sunlight before the application process and there should have been no rain for at least four hours before. The drying time is usually anything up to a maximum of three hours. As damp conditions may adversely affect the drying process the ideal months for applying fire retardant sprays is between the end of March and the end of October.

Safety in Thatched Homes

Many insurers perceive there to be an additional fire risk in buildings of this type but if well looked after by an owner who is aware of their “responsibilities” of owning such a property we feel they are a good risk to insure.

Although homes with thatched roofs are statistically no more likely to catch fire than those with more conventional roofs, because thatch is designed to be water repellent, it can be very difficult to extinguish a fire once it has taken hold. The materials used in thatching burn extremely quickly and, as a consequence, fires in thatched buildings can be devastating.

90% of fires in thatched properties begin due to a fault in the chimney or flue. Precautions that may be taken against fires starting from chimneys or flues include;

Do not build, rebuild or design chimneys without expert advice.
Keep the chimney swept regularly. Twice a year is advisable or quarterly if wood is burnt.
Ensure the top of the chimney stack is 1.8 meters above the thatch. This allows sparks to escape and burn out before settling on the thatch.
Have the chimney checked to make sure that the brick or stone is in good condition where it passes through the thatch.
Insulated lining should be fitted where the chimney passes through the thatch and it is also a good idea to have the chimney lined.
A flue thermometer can be installed to keep a check on the flue temperature.
If the chimney is used by an appliance that results in flue gases it should always be installed according to the manufacturers specifications.
Smokeless fuel is better than peat or coal and any wood burned ought to be resin free, well seasoned and dry. Wet unseasoned wood results in greater deposits in the flue and poses a fire risk.

Other fire precautions inside the thatched property include;

Do not use blow lamps within the roof space i.e near to the thatch.
Do not use heat or flame paint strippers for the removal of paint on surfaces near to the thatch.
Do not install any recessed lighting into ceilings below the thatch.
Ensure that any tradesmen working on your property know the risks of fire from naked flames.
Have the electrics in your thatched home checked every few years.
Have smoke alarms fitted throughout your home. If there is a loft space then it is advisable to have an interlinked smoke alarm as fires that begin in the roof or loft space may not be immediately apparent.
Electrical wiring in the loft space should be run in fire resistant ducting.
A loft hatch of minimum dimensions 600×900 cm should be easily accessible, and the loft should be kept free of storage.
Install fire extinguishers and a fire blanket.
Check the roof space regularly for signs of mice or other vermin as they can cause damage to electrical wiring thus posing a potential fire risk.

Fire precautions that may be taken outside the property are;

Do not mount external floodlights below the thatch overhang as they produce a lot of heat.
TV aerials should be fitted to a gable end or to a free standing pole in order to discourage lightening strikes.
Do not have barbecues, bonfires or firework parties within 100 meters of the property. If it is necessary to light a garden fire then always check wind direction and ensure that it’s prevailing direction is away from the house. Try to avoid lighting a fire in hot, dry conditions.
Install an outside tap with a hose long enough to reach around the property and onto the roof. Ideally this should be lagged against frost.

At Highhouse Insurance Services we provide insurance for thatched homes. We offer cover for your building, your contents or both in a combined policy. We assess each case on its merits and look forward to hearing from you if you own one of these historic properties. The bulk of thatched property that we insure is over 150 years old; however, thatch is making a resurgence as a roofing material and we are equally pleased to discuss your requirements for more modern property.

Via our Lloyds of London Underwriters, we are able to offer terms on many types of Thatched property. We cover the older style which may be listed and have non-conventional materials contained within their walls through to modern buildings with thatch covering and we are pleased that this quintessentially British type of property is enjoying a much deserved renaissance at the moment.

We look forward to hearing from you if you have any questions about insurance for thatched property including all grades of listed building.