Membrane to go behind cladding

[jamesd]

Well i'm near to the stage of putting the timber frame up for my shed and getting on with the cladding. But before i go any further i was wandering if i should put a membrane on the frame before the cladding goes on?

Not done any building work before so its all new to me, but i was thinking of something like this:

Protect A1 Roofing Underlay 1 x 15m | Roof Insulation | Screwfix.com

[ArthurBottlesworth]

You definately need a waterproof membrane

Guys who put my shed up 'forgot' to do it

It was a massive job to get it in afterwards

 

Not surecabout your choice of membrane they make stuff for the job

But others on here will know exactly what you want

[openspaceman]

You definately need a waterproof membrane

Guys who put my shed up 'forgot' to do it

It was a massive job to get it in afterwards

 

Not surecabout your choice of membrane they make stuff for the job

But others on here will know exactly what you want

 

Tyvek?

[agg221]

You want a breathable membrane rather than waterproof - doesn't let rain in but lets vapour out, to reduce condensation and prevent trapped water between the membrane and the wood where it contacts, leading to rot.

 

I am using Cromar Vent 3 - the Original is the heaviest duty one. You can get some decent deals on this on Ebay.

 

Alec

[Mull]

Good quality cladding and decent ventilation, then membrane is not so vital, if pennies are not an issue you can pay a lot for it!

[codlasher]

Your local builders merchant will probably stock Tyvek and a cheaper version.

Tyvek is the Rolls Royce of breathable membranes. For a shed I'd look at cheaper types.

One roll of tyvek will do one side of an average sized house roof as there's quite a lot on a roll.

Alternatively, chat up your local roofing company and see if they'll sell you a length (measure what you need firstly!)

codlasher

[Justme]

Tyvek, Rubberoid or similar.

[SteveA]

We have Tyvek breather membrane in the roof of our house, seems to be good stuff and I'm thinking of using it for our timber barn. Cheers, Steve

[Pete Bannister]

Jamesd, previous comments are correct; you don’t need a waterproof barrier behind well-designed timber cladding (unless its a partial rain-screen type cladding). The product you identify is probably not a good idea for your shed.

 

A vapour permeable membrane ('breather membrane') will reduce air-filtration /draughts if heat gain or loss is your concern. As others indicate, that’s a better option. But even so called breather membranes are not always a good thing.

 

Photo show condensation-related mould growth in a traditional roof construction where a high-quality 'breather membrane' has been used. You can see the grey mould and if you look carefully you'll see the condensate droplets too.

 

Effective building is more about the way you use materials rather than the materials themselves.

[SteveA]

Jamesd, previous comments are correct; you don’t need a waterproof barrier behind well-designed timber cladding (unless its a partial rain-screen type cladding). The product you identify is probably not a good idea for your shed.

 

A vapour permeable membrane ('breather membrane') will reduce air-filtration /draughts if heat gain or loss is your concern. As others indicate, that’s a better option. But even so called breather membranes are not always a good thing.

 

Photo show condensation-related mould growth in a traditional roof construction where a high-quality 'breather membrane' has been used. You can see the grey mould and if you look carefully you'll see the condensate droplets too.

 

Effective building is more about the way you use materials rather than the materials themselves.

 

Interesting, which make of membrane is that? Cheers, Steve