Thatched Roof Fire Protection – A Guide to Fire Prevention
There are few disadvantages to thatched roofing as compared to slate, asphalt tiles and other materials. The most significant disadvantage is the fact that thatch is combustible. Once a fire starts in a thatched structure, that structure is more likely to suffer damage directly related to roofing materials. Property owners with thatched roofs should, therefore, take certain precautions to ensure the safety of their buildings. Thatched roof fire protection is part of the package of ownership.
Statistically speaking, thatched structures are no more likely to catch fire1 than those with more conventional roofs. The problems don't arise until a fire actually starts. So the goal of thatched structure owners is to prevent fires from occurring. Remember just how valuable an ounce of prevention is worth.
Primary Causes of Thatched Structure Fires
Reducing the risk of fire in a thatched structure is a matter of taking the necessary precautions and using a bit of common sense. The Thatch Advice Centre has printed a comprehensive brochure explaining the basics of thatched roof fire protection. It can be downloaded freely from their website
According to the brochure, the top four causes of thatched structure fires are:
1. Chimney related (loose embers, etc.)
2. Electrical problems
4. Discarded cigarettes and external fire sources.
Chimney-related fires account for approximately 90% of all fires reported in thatched structures. For example, imagine a fire burning in the fireplace on a windy day. If embers escape up the chimney and are blown onto the roof by the wind, the possibility of a fire starting is very real. Loose embers inside the home can also be a threat.
Proper Precautions for Thatched Structures
The Thatch Advice Centre recommends owners of thatched structures contact their local fire services for specific advice on how to prevent fires and, in the event one does occur, help the fire service mitigate the damage. Below is helpful information relating to six specific areas. Following this advice should significantly reduce the risks of thatched structure fire.
Chimneys in thatched structures should regularly be inspected by a registered chimney engineer to ensure integrity. Any hidden sections of the chimney should be checked by a thatcher when any work is done on the roof. Other safety precautions for chimneys include the following:
Chimney pots should be at least 1.8m above the thatch
Chimneys should be swept semi-annually; quarterly when wood is burned
Spark arrestors should be avoided in thatched structures
Liners meeting local regulations should be installed
Register plates should only be installed with the help of an experienced professional.
Electrical problems are the second most common cause of fires in thatched structures. In order to prevent such fires, owners of a thatched structure should take the following cautions:
Electrical systems should regularly be inspected to ensure integrity (some insurance companies now require this)
Any and all wiring connections must be spaced at least 30cm away from thatch and wire netting
TV aerials and dishes should be installed on poles or gables rather than attached directly to the roof
Any overhead electrical feeds should be insulated with ceramic insulators
electrical wiring in the roof space should be contained inside metal conduit
Loft space should be protected against rodents that might otherwise damage electrics
Light fixtures in the roof space should be enclosed in the bulkhead; recessed lighting should never be used
External halogen lights should never be installed close enough to thatch to cause a fire via heat transfer.
3. Stoves, Burners and Fireplaces
Many property owners use stoves, burners and fireplaces for internal heat. Obviously, such cases present an additional risk for structure fires. Before installing any sort of burner inside a thatched structure, property owners should speak with their insurance companies to make sure this will be allowed.
Next, a thatcher should be consulted for advice on the best location for the burner and the safest way to install it. Third, only a licenced professional with experience should be allowed to install the burner inside a thatched structure.
When selecting a new unit, consumers should stick with the smallest possible unit that will provide the desired amount of heat. Always get professional advice when making a purchase. In cases where burners already exist, property owners need to ensure they are in proper working condition AND safe before lighting a fire.
4. Roof Voids
Roof voids present an extra level of danger in thatched structures because they tend to be bone dry. It's critical to avoid creating any sparks in the spaces. Therefore:
Hot work should never be conducted in roof voids
Compression or push fittings should be used by plumbers in these spaces
Frozen pipes should be thawed with hot water – never a blowtorch, hair dryer, etc.
Smoking, candle use, and lighters should all be prohibited in roof voids
Lofted areas should be kept clean and clear of clutter in case there is a fire
Fire-resistant covers should be used on all access hatches.
5. External Fire Sources
External sources of fire abound, especially in rural settings. Property owners should be extremely careful with anything external that poses a potential fire hazard. For example, halogen security lights generate considerable amounts of heat; they should never be installed within proximity of a thatched roof.
Additional precautions against external fire threats include the following:
Property owners should never start bonfires or use Chinese lanterns or fireworks on their property
Barbeques should only be used well away from the structure and downwind
Property owners should inform neighbours about the risks of bonfires, fireworks, barbeques, etc.
6. Fire and Smoke Alarms
Every home in the UK should be fitted with fire and smoke alarms. In the case of thatched structures, these alarms are much more important. Beginning with smoke alarms, at least one should be installed on every level of the structure with a thatched roof. This includes loft space. Smoke alarms should regularly be tested – twice annually at the change of daylight saving time is a good policy.
As for fire alarms, these are useful as early warning systems in the event a fire does occur. Fire alarms come in lots of different forms including chimney heat alarms, optical alarms, and ionisation alarms. Each of them has unique properties that make it effective for early detection of structure fires.
Fireproofing Thatched Materials
Thatched roof fire protection is something thatchers should be thinking about when they plan a job. There are three kinds of materials they can use to fireproof thatch: thatch batts, aluminium barrier foil, and fire retardant spray.
Thatch batts are fire-resistant slabs installed to the underside of a thatched roof to provide both fire resistance and thermal/acoustic insulation. Used alone, they slow down the progress of a fire in order to give occupants more time to get out. Used in conjunction with aluminium barrier foil, they provide total fireproof protection.
Aluminium barrier foil acts as a reflective insulator against excessive heat. It is essentially heavy gauge aluminium foil that conducts neither heat nor electricity. It is applied to a thatched roof in the same way felt is applied to a conventional roof.
Lastly is fire retardant spray. This spray, when applied to the exterior, provides both fire protection and an additional layer of water resistance. Fire-retardant spray is non-toxic, biodegradable, and can last for as long as ten years. It can also be used on the interior of the structure to protect the underside of the roof.
Be Safe with a Little Common Sense
We want to reiterate the fact that thatched structures are no more likely to catch fire than structures with conventional roofs. However, there are greater risks involved when a fire does start. If property owners simply exercise a little common sense along with taking the precautions outlined in this article, they can rest assured their structures will be safe.