At present there are 3 certified products used to make a thatched building fireproof.
Used in combination, these three products give maximum fire protection and will provide an AA fire rating (as certified by the UK's largest safety laboratory, The Loss Prevention Council, in Test Report #TE86794). We also keep ourselves constantly updated on fire safety products. As they become certified we will offer them.
While the highest fire rating is needed for public and commercial properties, less stringent requirements are usually in place for homes. A combination of one or more fireproofing technologies will often suffice to meet local fire codes.
The Thatchbatts and Foil work by phyically insulating the house interior from the thatch. The Spray protects the thatch itself with a non-toxic, bio-degradable, and odourless fire retardant.
"Thatchbatts are non-combustible, high quality resin bonded lightweight Rockwool slabs, designed to provide fire protection to the underside of thatched roofs on new builldings and/or extensions to existing buildings. They will also provide thermal and acoustic insulation." (Thatching Advisory Services Limited)
As shown in this diagram, thatchbatts are installed between the roof rafters. When used in conjunction with Aluminum Barrier Foil, Thatchbatts provide a total fireproof barrier between the thatch and the house. While thatchbatts won't prevent thatch from catching fire from external sources, they effectively shield the thatch from wiring and internal sources of fire.
Most importantly, they provide a wide margin of time to safely evacuate a thatched building whose roof has caught fire. Just as a fireproof door gives twenty or thirty minutes protection in a conflagration, so too the Thatchbatts provide effective safety margins for building evacuation.
Barrier Foil acts as both a fire resistant barrier and a thermally reflective insulator. An added advantage is that, once it is fixed to the roofing laths, the foil provides a weatherproof covering to the the roof during the thatching operation, thus avoiding the necessity of using tarpaulins, etc.
Barrier Foil contains no flammable materials. It is a heavy guage aluminum foil specially selected for its combination of strength and fire resistance. The foil is applied in exactly the same manner as traditional roofing felt. Like felt, the foil has minimum of 50mm overlap between horizontal joints so that there is no avenue for rain or fire to penetrate.
The Thatch Company uses Barrier Foil 341 which has been tested in accordance with specification BS476: Part7:1971, Surface Spread of Flame. In this test, conducted by the UK's largest safety laboratory, The Loss Prevention Council, Barrier Foil 341 achieved a classification of Class 1, the highest possible.
When combined with Thatchbatts, the level of protection to the interior of a building is the highest possible. On its own, the Foil provides a high degree of protection, but evacuation times would not be as long as with the thatchbatt/foil combination.
The Thatch Company uses the same safe sprays which protect the rebuilt Globe Theatre in London. As a certified operator with team members specially trained in the application of this spray, we will be able to supply you with a certificate of application detailing the size and volume of solutions used. This is crucial for insurance purposes.
We use Magma TAS Firestop sprays, two fire retardants designed and tested specifically for use on thatched buildings. There are two varieties - an indoor and outdoor spray.
The outdoor spray is sprayed directly onto the surface of the roof. Not only does it provide fire retardant capabilities, but it is also water repellent. This impregnation product cannot be washed out and is a special protection against leaching. The indoor spray is used on the internal surface of the thatch and the supporting timbers.
Magma TAS Firestop has been tested not only to NEN 6063 in the Netherlands, DIN 4102/7 in Germany but also BS 476 Part 3 (1958) in the United Kingdom and achieved EXTS:'BA' rating (Test Report TE 85766). This is the highest rating achieved by a fire retardant designed for thatch. In the British test, Magma TAS Firestop achieved the highest rating 'A' for its ability to retard the spread of flame and protected the roof for well over half-an-hour. It also scored 'B' in the penetration assessment.
While the protection may last for up to 10 years, we recommend testing the roof every 5 years to assess the degree of protection with a view to respraying if necessary. The internal spary does not require any assessment or retreatment provided the thatch is maintained in good order.
Magma TAS Firestop is non-toxic, bio-degradable, odourless, non-shrinking, and does not affect other materials in any way. It is fast penetrating and drying (maximum 3 hours) and has minimal environmental impact. It is produced to ISO 9002 standards.
Smoke Alarms - Don't forget them!
No matter what your roof material, you should have an adequate number of smoke alarms in your house. The Thatch Company leaves installation of smoke alarms to your electrician, but just wants to remind you that any house of any type without smoke alarms is a danger to its inhabitants.
The Thatch Company