Thatch Fire Protective Membranes

There are many fire membranes on the market which claim to be ‘suitable for use beneath thatch’.

Are they suitable? What’s the difference?

Nearly all fire membranes are PU (polyurethane) coated.

PU28 is often asked for and is widely used to describe fire barriers within the thatching industry. PU28 was used as a development code for a new membrane product and this code has stuck with many membranes to this day.

There are many formulations for a PU coating, some more economical than others. Some are solvent based, while most standard PU finishes would certainly fail a smoke & toxicity test.

A thatch fire membrane, PU or other may have a BS type test. What test? The testing it carries may not be an indicator of a product’s quality as some tests are not as robust as others and may not be reflective of the environment in which the product is used.

Waterproof, water resistant and breathable.

Waterproof can be defined as an objects’ capacity to be impervious - water won’t get in.

Water resistant means water isn’t going to get in easily.

Breathable

An often used but nonsense adjective. Membranes cannot breathe.

A ‘breathable’ membrane (or breather membrane) is water resistantandair permeable. The majority of air permeable products will have a high moisture/vapour transmission rate but will not breathe.

Check if a product is classified as both waterproof and breathable. If stated, this is incorrect. It will be one or the other - it cannot be both!

TAS - Thatch Firewall Membrane

Manufactured in the UK.

Looks and feels similar to a PU28 type membrane but with a far superior coating – a temperature resistant aluminised polymer system.

Tested beneath a combustible material - thatch - to meet both BS476-3:2004 & BS EN 13501-5:2005.

Designated as Broof (t4) - the highest performance in accordance within the European class - BS EN 13501-5:2005, which refers to four separate tests. The suffix (t4) indicates that Test 4 is to be used for the purposes of Approved Document B (Fire Safety) B4 External fire Spread.

Water resistant and tested for air and water vapour permeability.

Tested to meet the same smoke and fire toxicity specification for commercial aircraft. These are just a few of the tests carried out on the  TAS Thatch Firewall Membrane.

When considering a PU28 type fire barrier for use beneath thatch, it is worth asking a few more pertinent questions to ascertain its suitability.

For further details and information about TAS Thatch Firewall Membrane, please call the office.