Editing Thatching (section)

== Flammability ==
[[Image:House river kwai.jpg|thumb|right|River houses on the [[Khwae Noi River|River Kwai]]]]
Thatch is not as flammable as many people believe.<ref>{{Cite news |last=Bond |first=Rachel |date=March 20, 2004 |title=Tried and trusted thatch still comes out on top |url=https://www.telegraph.co.uk/finance/property/3323130/Tried-and-trusted-thatch-still-comes-out-on-top.html |access-date=June 29, 2024 |work=[[The Daily Telegraph]]}}</ref><ref>{{Cite news |date=August 9, 2014 |title=No job too big or small for thatching |url=https://www.independent.ie/regionals/wicklow/bray-news/no-job-too-big-or-small-for-thatching/30486832.html |access-date=June 29, 2024 |work=[[Irish Independent]]}}</ref> Thatch is said to burn slowly, "like a closed book," as has been stated by individuals familiar with the material.  The vast majority of fires are linked to the use of wood burners and faulty chimneys with degraded or poorly installed or maintained flues. Sparks from paper or burned rubbish can ignite dry thatch on the surface around a chimney. Fires can also begin when sparks or flames work their way through a degraded chimney and ignite the surrounding semi-charred thatch. This can be avoided by ensuring that the chimney is in good condition, which may involve stripping thatch immediately surrounding the chimney to the full depth of the stack. This can easily be done without stripping thatch over the entire roof. Insurance premiums on thatched houses are higher than average in part because of the perception that thatched roofs are a fire hazard, but also because a thatch fire can cause extensive smoke damage and a thatched roof is more expensive to replace than a standard tiled or slate roof. Workmen should never use open flame near thatch, and nothing should be burnt that could fly up the chimney and ignite the surface of the thatch. [[Spark arrestor]]s usually cause more harm than good, as they are easily blocked and reduce air flow. All thatched roofs should have smoke detectors in the roof space. Spray-on fire retardant or pressure impregnated fire retardants can reduce the spread of flame and radiated heat output.

On new buildings, a solid fire retardant barrier over the rafters can make the thatch sacrificial in case of fire. If fireboards are used, they require a ventilation gap between boarding and thatch so that the roof can breathe, as condensation can be a significant problem in thin, single layer thatch. Condensation is much less of a problem on thick straw roofs, which also provide much better insulation since they do not need to be ventilated.