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Thatched Domestic Premises - Fire Precautions [Hardfacts]


Although the incidence of fires in thatched houses is proportionately about half that occurring in conventionally built houses, precautions do need to be taken to help ensure the risk of fire is minimised. This Hardfacts outlines the problems encountered, the main causes of fire and key action points for the reduction of potential fire hazards.

Problems Encountered

Thatching materials are environmentally friendly, relatively cost effective with good sound and thermal insulation properties but they are combustible and rapidly burn out. Properties are often in rural areas remote from the Fire and Rescue Service where water supplies are frequently poor. The Fire and Rescue Service also face the challenge of extinguishing a fire in a roof which is designed to repel water.

The main causes of fire are: chimney related (which account for about 90%), Electrical faults, Lightning affecting the television aerial on the roof, discarded cigarettes, (garden) bonfires and contractors.

Steps to reduce fire risks are:


  • Ensure the mortar is 'sound' throughout the length of the chimney stack together with associated linings and timbers, every 3 years. A Thatcher should check the hidden section when re-thatching. Note that when wood is used, as a fuel, soot and tar build up rapidly and tar can degrade any lime based mortar.
  • Ensure the top of chimney pots are at least 1.8 metres above the ridge
  • Multi fuel stoves generate a lot of heat even through sound brickwork, particularly if the flue is only single brick thick (common in pre 1960's houses) - a vertical heat barrier is recommended between the thatch and stack. Consider also a flue liner.
  • Have the chimney swept along its entire length by a competent person at least twice per year, preferably before and after the main burning season.
  • Do not burn wet or unseasoned wood, as this will leave greater deposits in the flue.

Spark arrestors

These are no longer recommended as they can become clogged (either naturally or through a lack of maintenance) - restricting the free flow of combustion gases. If in place, ensure regular cleaning when the chimney is swept.


  • Check and test the electrical installation by a qualified electrical contractor at least every 10 years
  • Loft wiring should be in conduit but not attached to rafters which carry the thatch
  • Use of RCD's advisable
  • Do not place high wattage security lights near the thatch/overhangs
  • Do not cut recessed lighting into the ceilings below the thatch
  • Use bulk head light fittings in the roof space
  • Overhead electric supply cables need to be prevented from coming in to contact with the thatched roof or nearby trees

TV aerials/satellite

Avoid fitting these lighting attractors on or near chimney stacks. Preferably fit on a freestanding pole at least 6 metres (19 ft) from the building. Fix the aerial cable to a brick wall avoiding contact with the thatch.

Overhead telephone lines

Stop telephone lines coming in to contact with the thatched roof or nearby trees.

Contractors - Avoid hot work if at all possible

  • Plumbers in loft areas need to use 'push' or compression fittings
  • Decorators must not carry out hot work in the roof space or on windows just below the thatch

Attic Access

Provide access to all sections of the loft for (Fire and Rescue Service) fire fighting, large enough for a fire fighter with equipment and also access to any fire detection. Cover(s) to be at least 60cm x 90 cm, providing a minimum of 30 min. Fire Resistance.

Attic Storage

Combustible materials should not be stored in the roof space. Keep clear of old thatch, straw dust and other debris.

Wire Netting

Fit in a way acceptable to the fire service (who need to be able to lift the netting to allow water to penetrate and not just 'run off' the roof).


  • Avoid fireworks and avoid bonfires. Remember wind directions change rapidly
  • Warn neighbours of the danger of having a bonfire in their gardens, if near the house
  • Avoid barbeques close to the house


No smoking to be allowed when in the loft space or working on or close to the thatch.

Automatic Fire Detection

Provide early warning by fitting mains operated smoke detectors preferably by a third party accredited installer - on each level and especially in the roof space.

Fire Extinguisher

  • Have fire extinguishers readily accessible suitable for electrical or cooking based fires, serviced on an annual basis by an appropriate competent contractor
  • The kitchen area should contain a fire blanket

Hose Reel

Have a hose outside permanently connected to a water supply which reaches around the house and from which a jet of water is able to access all parts of the roof.

Fire and Rescue Service

  • Be aware of the nearest hydrant or potential source of water
  • If the house is in the countryside have the six figure Ordnance Survey map grid reference ready together with clear instructions for the best way a large vehicle can get to the building. Keep these details in a prominent place near the telephone.

Restricting the Spread of Fire

Consideration should be given to the:

  • Provision of a fire resistant boarding beneath the thatch but above the rafters, when re-thatching. Boards are usually rockwool or calcium silicate based and can give up to 60 minutes fire resistance - helping to stop a fire in the thatch entering the house or a fire in the house entering the thatch.
  • Use of fire retardant sprays on the thatch. Designed to give up to 10 years protection these need specialist checking after 5 years.
  • Provision of vertical fire barriers in very large open spaces - such as in a terraced block. The provision of a 60 minute fire resistant barrier would help slow the fire spread in the roof space and also help reduce smoke damage.
  • Fitting of a simple 'sparge' pipe (concealed within the thatch) to deliver water along the ridge, with a connection at ground level for the Fire and Rescue Service to connect a water supply.

There may be a conflict between fire safety and thatch conservation as noted below:

  • Unless fire resistant boarding is carefully designed and kept well back from the underside of the thatch the lack of ventilation may reduce the life of the thatch
  • The use of fire retardant sprays may affect the performance of the roof
  • It must be ensured vertical fire breaks do not unduly affect any ventilation the thatch may require.

Expert advice should therefore be sought before undertaking any of these fire protection measures.

Sources of Further Information

Next Steps:

  • Source discounted products, available to Aviva insured customers and brokers only, via our Preferred Supplier Scheme - click here to find out more about the savings you could make
  • View our Tools and Templates
  • Call our Risk Helpline on 0345 366 66 66
  •  Email us at

Please Note
This document contains general information and guidance and is not and should not be relied on as specific advice. The document may not cover every risk, exposure or hazard that may arise and Aviva recommend that you obtain specific advice relevant to the circumstances. AVIVA accepts no responsibility or liability towards any person who may rely upon this document.

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