Membranes

Timber frame membranes for roof and wall

A timber frame membrane manages moisture and air movement through the building envelope, protecting the structure and improving energy performance. At TimbA Systems we supply the Rothoblaas range of breathable membranes, vapour control layers, and air-control products for timber frame construction in the UK, backed by engineering advice on how each layer fits into the overall build-up.

Breathable membranes vs vapour control layers

The two are easy to confuse but do opposite jobs. A breathable membrane sits on the cold, outer side of the insulation, keeping wind and water out while letting water vapour escape so the structure can dry. A vapour control layer sits on the warm, inner side and limits how much moisture enters the construction in the first place. Getting the right membrane on the right side of the insulation is fundamental to a healthy timber frame, and is one of the most common detailing questions we help with.

Where membranes are used

• Roof construction: breathable underlays that shed water while allowing the roof build-up to dry.
• Timber frame walls: wind-tight breathable membranes behind cladding and ventilated façades.
• Airtightness: vapour control layers and air-control membranes that cut heat loss and meet modern energy standards.
• Mass timber protection: temporary and permanent membranes that protect CLT during and after construction.

Matching the membrane to the build-up

Membrane choice also depends on the specifics of your construction. A warm roof, a cold roof, and a ventilated façade each place different demands on the breathable membrane and vapour control layer, and the insulation type and thickness influence how much vapour resistance you need on the inner face. Specifying the wrong combination can trap moisture in the structure, so it is worth confirming the full layered build-up before you order. Our team can sense-check your roof and wall make-ups against the membranes you are considering.

Sealing the system

A membrane only performs if its joints, laps, and penetrations are sealed. We supply matched tapes and sealants alongside the membranes so the airtight or watertight line is continuous, which is what makes the difference between a membrane that works on paper and one that works on site.

Expert membrane specification

Choosing a timber frame membrane is about more than a single product; it is about the whole layered build-up. Our engineering team can advise on which breathable membrane and vapour control layer suit your wall or roof, how to detail the laps and junctions, and which tapes complete the system. Browse the range below, or contact us for project-specific advice with trade pricing and next-day UK delivery on stocked lines.