Thatched roof advice

Thatched properties are commonly associated with the West Country and in places within The Cotswolds. However, we do occasionally come across a thatched house within the areas covered by Woodward Chartered Surveyors; From Oxford to Oxford Street. Director and experienced Chartered Surveyor James Bush recently carried out a building survey on such a property in South Buckinghamshire and we have seen many examples in Amersham, Gerrards Cross, Chorleywood and Loudwater.

The house was built in 2002 and had a full thatch finish of Water Reed. This is a more robust and longer lasting material then straw under similar conditions whilst thatched houses are warm in winter and cool in summer. The thatch on this house had a full cover of wire mesh that provides longevity helping to prevent birds from pulling individual reed out from the covering to use as nesting material and although darkened due to rainwater ‘wetting’ was generally in good condition. In this regard a well laid thatched roof can provide a good roof cover for between 40 and 60 years assuming a good standard of initial workmanship and that it is subsequently well maintained thereafter. In this regard moss growth developing on a thatched roof should be regularly cleared as this can lead to premature deterioration by holding damaging moisture on the surface of the reed. This can lead to a loss of function and longevity. It can be removed but so should the damp reed below at the same time.

One area that commonly requires periodic maintenance is the ridge topping at the apex of the roof slopes. This is because it inevitably will suffer greater exposure to the elements. Thatch can also compress over time and so details such as the lead flashing about chimney stacks and bays must be periodically examined so that rainwater ingress does not occur about such a detail. Thatched roofs do not have rainwater goods attached to them as such can’t be readily secured whilst the density of the thatch and its ability to absorb rainwater that then subsequently dries mean that water does not pour off the roof eaves as it would from a conventional tiled roof.  

Thatched roofs are normally more expensive to insure than those with conventional roof coverings due to the increased fire risk and cost of materials although improved Building Regulations, fire safety guidance and a new generation of trained thatchers are helping to reduce thatch roof fires. Statistically a thatched roof is no more likely to catch fire than a conventionally tiled house its just that they spread quicker and are harder to extinguish.

Further detailed advice on thatched roofs can be found at The Thatched Advice Centre

So, if you have a thatched house, take care to ensure that it is well maintained as by so doing it will maintain your investment.