Fire Precautions

Between ten and thirty serious thatch fires occur in Britain every year. Fires in thatch take hold quickly, are extremely difficult to extinguish and are usually very destructive.

The risk of thatch fire is less than it was once thought to be, but owners of thatched buildings should avoid complacency.
Sensible precautions can and should be taken. Many of them are simple, cheap and easy to live with and the key to living under thatch without undue anxiety about fire.
The Fire and Rescue Service offers comprehensive advice on fire safety measures, free of charge. If nothing else, contact the fire service and confirm that your property is recorded as thatched on their mobilising system.

All owners/occupiers of thatched houses should be prepared for providing the fire service with the information they need, should an emergency arise. This will be the current formally recognised address, a six figure grid reference and clear instructions for the best way for a large vehicle to get to the building.

Fire fighters should also be informed of the nearest supplies of water for fire fighting. This information should be in a prominent place, close to the phone for anyone who may be looking after the house. It should also be given to neighbours, along with a key, in case of fire when an owner is away.

Most thatch fires start because of a problem with the chimney or fireplace. Problems include design, condition and use. Sparks from a chimney or any other source landing on the thatch are no longer thought to be a very common cause of fire, but the top of the chimney or the chimney pot needs to be sufficiently distant from the thatch to allow free airspace for any burning material from the fire to be blown away.

Spark arrestors, which were once thought a sensible form of fire protection and were insisted on by some insurance companies, are now generally regarded as more of a hazard than a help, since it is difficult to keep them well-maintained and without regular maintenance they may clog up and become a hazard. The condition of the chimney shaft, especially where it abuts the thatch, is critical and should be kept in good repair.

The thatcher is the only person likely to see the 'buried' section of the stack in the thatch and should be asked to check the soundness of the construction (which may be masonry, brick, or cob) when rethatching.

If the building is listed and either the inspection or remedy (or both) might cause damage to roof timbers, the owner should ask the advice of the conservation officer as well as the local Fire Safety Officer.

Thatch fires have to be dealt with in a very specialised way by fire fighters. Thatch is designed to throw off water, and this means that the most effective approach is not simply to hose down the thatch, but to pull it off beyond the fire. An owner should ask their thatcher to fit wire netting in a way acceptable to the fire service, making sure that it can easily be removed and causes no delays if there should be a fire and the thatch has to be pulled off the roof.

The high temperatures that modern owners expect from woodburners and fires has meant that Fire Safety Officers now recommend a vertical heat barrier between the chimney shaft and the thatch, within the thatch, to avoid the transmission of heat from the chimney shaft to the thatch, causing it to become dry, smolder and eventually burn. These are best fitted when a roof is being rethatched. Flue linings and wood-burning stoves, if incorrectly fitted (which they often are) or defective can cause fire.

Chimneys should be regularly and frequently swept to clear away combustible soot crust and bird nests. This may be as often as four times in a burning season, depending on the chimney and the fuel. A competent sweep should be able to advise. If wood is used it should be seasoned and logs ready for burning should be stored where they are not at risk from catching fire from a spark.

Any proposed change to the way a fireplace is used or the way a room with a fire is ventilated should be thought through in terms of any risks it might bring to the thatch and owners should seek the advice of the Fire Safety Officer. Free advice from the local Fire Safety Officer is an under-used service.

Electrical installations in or near thatch are a common cause of fire. Thatch insurance companies have good reasons for insisting on a high standard of safety in electrical installations in thatched houses.

Most require a smoke alarm under the ridge of the thatch, connected to alarm systems in the rest of the house. If they do not, it is sensible for owners to have one fitted anyway and ensure that it is well maintained.

The use of electrical circuits in or near thatch should be kept to a minimum and, where possible, electrical installations should be designed in conjunction with the advice of Fire Safety Officers. Wiring in or near thatch should be run in trunking or conduits, and lights in roof spaces should be enclosed to protect thatch from heat or electrical faults. No wiring should be run under the eaves as there is a risk that it could be cut accidentally by thatchers.

Any contractors, particularly plumbers or painters, who may use equipment or processes that produce heat and are working under or near thatch, should be asked to think of alternative ways of working and produce a written specification to the owner of what they intend to do and a statement of their insurance position. If in doubt, owners can always ask the advice of local Fire Safety Officer or Building Control Officer.

There can be conflicts of interest between the needs of fire safety and thatch conservation. Fire resistant board or impermeable membranes introduced under the thatch can reduce ventilation and may reduce the life of thatch, unless carefully-designed and kept well back from the underside of the straw or water reed.

Opportunities to insert boarding or membranes exist only if thatch is stripped back to the roof timbers, which is something to be resisted if the thatching material is of some age. Soaking thatch with fire retardants before use is known to have been used in the 1930s, and probably long before. There are modern versions of the system. English Heritage’s guidance note states that the balance of evidence 'seems to be against modifying the basic behaviour of the materials, which could adversely affect the roof's performance'.

Some roof spaces are divided up vertically by what can be old and interesting partitions. It makes good sense to have roof hatch access to every compartment of the roof space from the floor below, and big enough for a fire fighter with equipment to get through without a struggle. Good access to all parts of the roof space, which should be kept uncluttered, also allows both thatcher and owner to look at the underside of the roof, check the condition of the thatch and timbers from below and consider the interest of roof timbers and their details.

If timbers in a listed building are in poor condition and need repair or replacement the Local Planning Authority should be asked to advise. In listed buildings it is usually less damaging to the historic fabric to make ceiling hatches than trying to cut access through the vertical partitions in the roofspace, but there are exceptions and the advice of the Conservation Officer should be taken.