28 Jun 2016

How to reduce risk of fire and pests in thatched roofs


Thatch, known for being cool in summer and warm in winter, has been used as a roofing material for centuries. The Thatch Advice Centre was set up as an online resource to offer free up-to-date advice on ‘all things thatch’ and this has included liaising with fire services, building control, fire testing houses, Historic England, insurers and others in working on understanding and promoting fire safety. Here, Karen Crouch, Founder of The Thatch Advice Centre, offers her advice on fire safety for thatched properties.

Thatch isn’t more likely to catch fire, but gets bad publicity when it does because it is hard to extinguish (as it is designed to shed water). Recent research and investigations into thatch fires indicate that the major cause is ejected embers with the increased risk from wood burners with lined flues and low chimneys. Most thatch properties are unique, so assess each property, understand the risks and deal with them both for your peace of mind and insurance cover.

Ways to reduce the risk of a fire:

• Sweep chimneys regularly.

• Burn seasoned wood.

• Have a smoke alarm on each floor – join us on social media for #TestitTuesday reminders.

• Avoid bonfires, barbeques and fireworks in close proximity.

• Spark arrestors only work if cleaned very regularly.

• Check chimneys for birds’ nests before lighting (especially in spring).

• Think about the use of a fire retardant spray e.g. Magma Firestop.

• When re-thatching there are fire resisting barriers available to go over the rafters and under the thatch. Be aware of the difference between fire and fire resisting. The latter is most important as it gives protection from the heat as well as the flames. Think about thatch needing to breathe and be aware of Building Regulations and strict controls on listed buildings.

The Thatch Advice Centre offers free fire safety leaflets and website pages via its website. Be aware, take care and enjoy your thatch.


Timeless beauty:

Christopher Essex of Four Counties Thatching explains how to maintain your thatched roof.

There are regional variations with the type of material used, but whether your roof is water reed (commonly known as Norfolk reed), combed wheat reed or long straw the following maintenance tips apply:

Don’t let plants grow into the roof i.e, wisteria, roses, ivy etc and cut back over-hanging tree branches which can rub against the thatch wearing it away. Maintenance will improve the longevity of your roof and improve the appearance. Maintenance usually takes place whilst the roof is re-ridged. Common repairs include bird and vermin damage, while another common repair is removing moss.


Design, materials and unusual thatch

Traditionally trained Master Thatcher, Simon Crouch, talks about thatch from an aesthetic point of view.

With over 30 years’ experience of works in all three thatching materials, water reed, combed wheat reed and long straw, I have seen a great variety of various roof designs from Robbie Burns’ cottage to new build thatch. Some properties are straight front and back, others have windows, valleys or are even F-shaped or circular. Not only does roof design affect the look of a thatched building, but it can also affect the performance and therefore the longevity of a roof. A minimum roof pitch of 45º is recommended for best performance and allowance should always be made by architects for the thickness of thatch, especially between dormer windows. Valleys wear faster than straight roofs, as do the sides of dormers and under aprons and chimneys. Here, you will often see leadwork to take the brunt of the rainwear. Ridges can be block (raised above the coat work either straight cut or ornamental/patterned cut) or flush.

Chimney heights on new builds should be a minimum of 1.8m for Building Regulations and the size of the chimney is also an important consideration for installation of a wood burner, where consultation of a specialist is always recommended.

Not just houses, but cottages and barns are thatched, as it is a very versatile material. I have seen thatched gazebos, summer houses, toilets, Iron Age roundhouse replicas, lych gates and churches, windmills and even a bandstand. Vertical thatch panels have been used on a new building in East Anglia such as the one we did on Grand Designs Live and I recently re-thatched a very interesting set of buildings on the Hobbiton movie set in New Zealand.

It is good advice to get your architect to speak to a thatcher regarding designing a roof to make sure it will work properly.


Controlling problematic pests

Richard Bone, Managing Director of pest control company Des Bone, explains all you need to know about pest control within thatched roofs.

Pests of all descriptions are attracted to thatches. Mice tend to be one of the biggest inhabitants internally – usually field mice, due to location and that they are good climbers on external foliage. I have learnt that if a thatch has seed visible internally, mice have all the feed they could need for an over winter stay.

Rats will also exploit this situation, whilst squirrels and birds will cause a more visible external destruction to thatch. I am normally confronted with vast patches of thatch pulled out due to squirrel access, birds pulling the roof for nesting materials or insects embedded within the thatch. Insects are too numerous to list but on our radar are wasps, hornets and bumblebees, alongside honeybees, which are not as frequent as they tend to require a cavity. Wasps and hornets build a nest from scratch each year and it then grows to suit their needs.

Can you remain in control of your thatch?

Each time I visit a pest-related problem in a thatch, I look at each on its own merit. With bumblebees, I will do my best to leave them alone; they don’t tend to cause destructive measures to thatch. However, birds, squirrels, mice and rats do cause destruction to thatch, but you can remain in control of your thatch. Most reasons for failure is because there is no wire protection over a thatch or a cheap soft wire is used when originally installed – a poorly maintained thatch is an invitation for an infestation. Rodents chew constantly to keep their incisor teeth down. Poor wire or missing wire will also allow birds to exploit the thatch.

If you are an experienced resident living in a thatched property, constant monitoring of your thatch both externally and internally will help you stay in front of most pests. Also remember there are professionals all over the country that you can call on at any time to help you. The British Pest Control Association (BPCA) is a body of professional members, trained and certified to advise treatments and deliver solutions.


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