A breather membrane is the weather barrier that keeps a shed roof dry without stopping the roof from breathing. It goes over the rafters, below the felt, corrugated sheet or shingles, and it is the difference between a garden building that lasts a decade and one that rots from the inside. Eastopo supplies 60-220 gsm breather membrane rolls to shed and garden building manufacturers, cut to roll size and printed with the buyer's brand.
Why Shed and Garden Building Roofs Need a Breather Membrane
A shed roof gets the same weather as a house roof: wind-driven rain, frost, condensation on cold nights, and in summer, high roof-space temperatures that push moisture vapour out of the timber. Traditional bitumen felt keeps water out but also traps vapour, which is why felted sheds blister and the timbers underneath stay damp. A breather membrane sits outside the insulation line and lets that vapour escape, so the frame dries out between rain events instead of slowly rotting.
For uninsulated sheds the gain is smaller, but the membrane still protects the roof deck and keeps the interior cleaner and drier. For insulated garden rooms, studios and home offices, it is essential: without a breather layer, condensation forms on the underside of the roof sheet and drips onto the insulation.
Typical Shed Roof Build-Up
The standard build runs from outside in: roof sheet (corrugated metal, felt or shingles), battens, breather membrane over the rafters, then the roof frame. The membrane is laid with a slight sag between rafters so water runs to the eaves, laps follow the lower-sheet-outside rule, and fixings go through the membrane into the rafters. On small roofs one sheet often covers the full pitch, which is why shed manufacturers order custom-width rolls rather than trimming house rolls.
A 1.5 m x 50 m trade roll covers roughly 75 m2 of roof area, and we cut rolls to the exact width and length of a manufacturer's roof jig, so there is no site trimming and no waste at the factory.
OEM Supply for Shed and Garden Building Manufacturers
Shed, log cabin and garden building manufacturers buy membrane the way they buy everything else: as a spec component with their own brand on it. Eastopo prints the buyer's logo and product name on the roll at the factory, in the buyer's choice of gsm, width and roll length, and packs to the buyer's picking list. MOQ is one container with mixed grades and widths allowed, and production lead time is 25-35 days from deposit. We currently supply OEM membrane to distributors and manufacturers in the UK, EU, US, Australia and New Zealand.
Most garden building lines use the lighter half of the range. If your sheds are uninsulated, a 60-100 gsm grade keeps cost down; insulated garden rooms and offices take a standard 110-160 gsm grade. Heavier grades are for coastal sites and exposed positions. Send us the roof panel width and roll length you need, and we quote per square metre with the packing plan matched to your container.
Choosing the Right Grade
GSM (grams per square metre) is the first number a buyer checks. It tracks strength and robustness more than waterproofing - even the lightest grade is a fully functional vapour-permeable sheet. Eastopo produces the range from 60 gsm to 220 gsm made to order, so a shed manufacturer can spec one grade for the value line and another for the premium line without changing suppliers. Full technical data, including EN 13859-1 performance, sits on our breathable roofing membrane page, and the roof and wall overview is on our breathable building membrane page.
FAQ
Yes if you want the roof to last. Felt is a low-permeance layer, so any vapour trapped under it condenses on the deck. A breather membrane between the rafters and the felt lets the timber dry out and prevents blistering.Do I need a breather membrane under shed felt?
Uninsulated sheds take a lighter 60-100 gsm grade; insulated garden rooms and offices take a standard 110-160 gsm grade; coastal and exposed sites take heavier grades up to 220 gsm. Eastopo cuts all of them to your roll size.What gsm should a shed roof membrane be?
Yes. OEM printing with the buyer's logo and product name is done at the factory, in the buyer's choice of gsm, width and roll length. MOQ is one container with mixed grades and widths.Can you print our brand on the membrane rolls?
Production lead time is 25-35 days from receipt of deposit, covering grade, width, printing and packaging set-up. The exact schedule is confirmed in the quotation.How long does production take?
Rolls can be packed on pallets with edge protection, or shipped loose-packed without pallets where that gives a better container load factor. The packing plan is matched to the container to maximise utilisation.How do you pack shed membrane rolls?
About the Author
Written by J. Mao - Eastopo New Materials. J. Mao is the Export Manager at Hangzhou Eastopo New Materials Technology Co., Ltd., specialising in breathable membrane, roof underlay and building envelope products for the UK, EU, US, Australia, New Zealand and other export markets worldwide. He has worked on OEM supply programmes for roofing distributors and timber frame manufacturers since 2016. For project specifications, samples and distributor pricing, contact J. Mao by email at mj@eastopo.com or on WhatsApp +86 193 5725 8106.
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