Fire Barriers, Retardants & Systems

Existing Thatched Properties

A thatch fire barrier system can only be installed in the conventional way if the thatch is being completely removed and therefore exposing the rafters. Although in most cases Building Control Requirements don’t need to be achieved, we still recommend using either our Thatch Firewall Membrane or Thatch Fireboard system.

Although our fireboard system can be used on an existing property, in most cases due to the requirement for the provision of components such as a vapour check, we often find the Firewall membrane system being selected.

The Firewall Membrane system has the added advantage of being flexible, which can be essential on an existing roof that has old timbers that are not straight enough to accommodate the rigid fireboard type systems.

Find out more on U-Values and Condensation Risk Analysis.

All the products in each system are recognised by the NFU Mutual, which if installed in a thatched property, will enable homeowners to receive a reduction in their insurance premium. Many other insurance providers also recognise our products.


  • Certificate of Supply documents are available on request, additional information about the project may be required to enable these to be completed.
  • When selecting suitable products for your project please review the detailed information available in the system documents, to include taking into consideration other components that make up the complete roof system such as breathable membranes and vapour checks.
  • In addition to the required fire tests, each system has the relevant COSHH & MSDS statements and where required CE marking.

Products & Systems available:

Thatch Firewall Membrane

Thatch Firewall SystemThatch Firewall Membrane system is normally the preferred choice for existing thatched roofs, due to its flexibility, providing the Dorset Model requirements have not been requested. Find out more about Thatch Firewall Membrane System.

Thatch Fireboard System

Thatch Fireboard SystemThe Fireboard system can still be used on an existing building providing the rafters are straight and strong enough and consideration can be given the the provision of a vapour check. Find out more about Thatch Fireboard System.

Thatchsayf – Fire Retardant Spray

Thatchsayf Fire Retardant SprayIn addition to one of the fire barrier systems, the thatch can also be treated with Thatchsayf, a fire retardant spray.

Sometimes if a fire barrier system cannot be incorporated into the roof, then having the thatch treated with a product such as Thatchsayf is the only option left available. Find out more about Thatchsayf.

Thatch Alert System

Thatch Alert SystemThatch Alert Chimney Monitor System has been specifically designed to monitor the temperature of the chimney brickwork at the point where it meets the thatch.

The system acts as an early warning device to inform the home owner of potential high temperatures. Ideally needs to be installed at a time when some thatching works are being completed, although it is possible for a thatcher to remove a small section of thatch to enable the system to be installed. Find out more about Thatch Alert.