The life of thatch will depend on many factors; these include pitch of the roof, roof design, type and quality of material used, geography, topography, and not least, the skill of the thatcher.
Trees should always be kept well back from thatch and never allowed to overhang or brush against the roof. Thatch performs well in windy situations even where water is present and where rainfall is heavy. Disturbing the thatch may shorten its life; avoid climbing on the roof or laying a ladder against the material.
The thickness of the thatch decreases over the years as the surface is gradually eroded. A thatched roof can be thought to be nearing replacement when the fixings are close to the surface. A roof is as good as the amount of correctly laid thatch covering the fixings. Good thatch should not require regular maintenance but it is important to report any faults to your thatcher as soon as possible. The life of a thatch can be extended significantly by appropriate repair and maintenance.
Establish, early on, what condition the thatch is in, and then appropriate work (if necessary) can be programmed. Re-ridging will be required several times during the lifespan of a thatch. The life of a ridge will vary depending upon the type, pitch, location and other factors. An approximate guideline would be 15 years. An untidy ridge may still be sound; seek advice as to whether repairs are really necessary as work may disturb a main roof that is still in reasonable condition. It is normal practice to renew the wire netting when re-ridging. Long straw thatching should always be securely netted to avoid bird penetration. Water reed does not always require full netting; however, the ridge should be netted in all cases. Take advice from your thatcher.