Various figures are quoted for the Lifespan of a Thatched Roof but what do these figures really mean?
If a thatcher says a water reed roof will last 40 years, does it mean that in its 41st year the roof will start to leak? Does it mean the roof will be beyond any kind of possible repair?
The answer to these two questions is usually no.
The first thing to make clear is when we talk about the lifespan of a roof we are talking about an average – just as the average age that men in the UK live to may be 80 – some live a lot longer and some a lot less. Factors which will lead a roof to deteriorating quicker would be a slack pitch, the roof being in the shade, weather conditions such as the roof being exposed to constantly strong winds, rain and /or high humidity and the use of poor quality materials and poor workmanship.
When a figure is quoted for the lifespan of a roof, it refers to the predicted time that it would no longer be cost effective to keep repairing the thatch and when it would be more prudent to renew the thatch even though the thatch may not be leaking, rotting or falling off the roof. A roof may be 40 years old and if repaired periodically could last another 20+ Years.
Factors which may influence re-thatching (assuming it is not leaking) may be the owner wishing to sell the property in a good as possible condition to command a better asking price or just the owner growing tired of looking at a patched up roof-there is after all nothing like admiring a newly thatched roof.
But there is no doubt that good maintenance is the key.