The appeal of thatch is undeniable; the combination of old-world charm and a `roses around the front door’ image is guaranteed to attract interest from purchasers. However, the practical buyer should arm themselves with all the facts about the issues involved with thatch before making a purchase.
This article tells you all you need to know about buying a thatched property. It explains:
- Fire risk
- Key points to consider
- How long a thatched roof lasts for
- Chimneys in thatched buildings
- Smoke alarms
- Maintenance of thatch
- Advice to owners of a thatched home
There are 60,000 thatched roof properties in the UK, and fire affects 50-80 of these a year (Thatch Advice Centre). In 90% of thatch fires, there has been either a wood burning stove in the property, a flexible chimney liner or no liner, or a combination of all these. Common causes of fire in thatch include sparks and embers from a chimney. Thatch fires are hard to control unless they are caught early, and most properties are destroyed as a result. However, while considered a fire hazard, statistically thatch is not at higher risk of catching fire than a conventional slate roof, providing that the correct procedures are observed and various fire safety measures are taken, which include:
◊ Rigid fire barriers or fireboards; while these will not eliminate the risk of thatch fire, they can reduce the amount of damage. Fitting generally involves a physical barrier being installed directly on top of the roof timbers and it can only be fitted if the thatch is stripped off, or on a new property.
◊ Thatch fireboard; this is a composite board which can be installed, usually on new roofs.
◊ Thatch firewall membrane is a flexible alternative suitable to use in existing buildings; it offers vapour transmission and breathability.
◊ Fire retardant spray can be applied to new or existing thatch and reduces the spread of fire.
◊ Chimney monitoring systems.
◊ If spark arrestors are fitted, they must be kept clean; they can become blocked with tar deposits, making it harder for flue gases to exit the chimney and allowing heat to build up in the flue.
What to consider before making an informed decision
- Thatch is a centuries-old method of roofing; it is effective, being cool in summer and warm in winter and thatched properties hold their value.
- Regular maintenance is required to keep thatched roofs in good condition.
- Is the property listed? A grade I listing may limit any potential alteration work.
- Assess the current fire safety precautions.
- Are the chimneys lined?
- Are the required smoke alarms in place? This will affect any insurance policy.
- The last date of a roof inspection, the date of any repairs or re-thatching and the name of the thatcher.
- Have there been any alterations or extensions?
- Find out what the thatching material is for both the coat work and the ridge.
- If there are open fires or wood burners in the property, obtain the date and details of installation.
- Have there been any vermin or bird problems in the thatch over the last five years?
- The date of the last electrics check: obtain the certificate.
- Who are the current insurers? A specialist thatch insurer will be required, however, insurance premiums are not normally more costly than those from a mainstream company.
- Consider a separate roof thatch survey – a thatcher will assess the condition of the thatch and advise when repairs may be needed.
- Are smoke alarms fitted and are fire extinguishers in place?
How long does a thatched roof last for?
The lifespan of a thatched roof depends on the thatching materials used. Water reed is the most durable and can last for up to 50 years; it will require re-ridging every 10-15 years and some patching. Combed wheat reed (which has been cleaned and hollowed out) is winter wheat straw with the leaf removed; it has a lifespan of 20-30 years, with re-ridging required at 10-15 years.
Another material is long straw, a winter wheat straw which is not combed and has a shorter life expectancy of 15-25 years. Other thatching materials include water reed thatch, cereal straw, flax, heather, broom and marram grass. Re-thatching a roof costs approximately £100-£125 + VAT per m2 of roof area.
It is important to obtain the last chimney check certificate; chimneys in thatched properties should be swept twice a year. If the chimney is lined, clarify the type of liner and inspect the HETAS certificate and any other documents. It is advisable to find out whether the chimney/and or liner has been inspected with CCTV and check the certification. Regularly check the chimney flue, stonework and bricks; air pockets, gaps or missing bricks could allow hot gas and smoke to escape, especially if there is a build up of soot or a bird’s nest. Unsuitable flue liners can be a fire hazard; chimneys serving an open fire or a multi-fuel fire must have the correct liner fitted. Another point to bear in mind is that the recommended height from the thatch to the top of a chimney pot is 1.8 meters.
It is important to fit alarms and smoke detectors on each floor and in the loft space; these should ideally be mains powered with a battery back-up and all alarms should be interlinked. It is advisable to install a heat detector in the kitchen along with a carbon monoxide alarm and a stove pipe thermometer should be fitted to the chimney flue to assess stove performance. Chimney heat monitors can check the temperature of brickwork at the point where it meets the thatch. Consideration could also be given to installing a sprinkler system.
Regular maintenance of thatch
On inspection, a thatcher can give an approximate lifespan for each part of a thatched roof. Before winter, it is advisable to clear leaves from drain gratings to allow water to escape. Other factors to consider include insulating exposed pipes as well as pipes and tanks in lofts; checks should be made of the central heating system and fire extinguishers and smoke alarms should be checked weekly. Electrical wiring should be checked every five years (check the length of time between inspections with the insurance company). Overhanging trees can cause moss growth in thatch and may need lopping.
Advice to owners of thatched buildings:
- Switch off unnecessary electrical items and lights.
- Have the correct fire extinguishers in place.
- Ensure tradespeople have the necessary qualification to work with thatched roof properties and are registered to the relevant approved bodies.
- Do not install recessed downlights in ceilings below a thatched roof; remove if these are already in position.
- Ensure lighting in the loft space is enclosed in a bulkhead fitting and fix away from thatch.
- When wiring in loft space, ensure the correct cables are used and enclose wires in suitable trunking or a conduit. It is advisable to avoid cables running through thatch and to keep external lights away from thatched roofs.
- Always use dry, seasoned wood: sap in wood is the main cause of tar deposits in liners or chimneys. Moisture meters can check the content of wood.
- Check that the overhead power supply is insulated.
- Do not overload sockets and extension leads.
Are you tempted to buy a thatched property?
Let us know what you think about thatch: perhaps you live in a thatched cottage – do the benefits outweigh the risk factor?