Plans for my garden room are nearly finished and I'm costing parts before going to SWMBO. Tyvek House Wrap is the stuff to use for wrapping timber framed buildings but its over £100 a roll. I only need 18m of the stuff. Is there a good alternative breather membrane? Breathable roofing felt can be had for 1/3 the price. Is that OK for use on walls?

I used IKO rubbershield light on my shed, all wall and roof under the tiles as recommended by the builders merchant, was around £18 a roll and is very good.

Much better than old bitumen soaked stuff.

We used buidbase own version of it a couple of years ago from memory it was about £42-45ish a roll rather than the tyvek at £100+ plus a roll and was very similar. Hope that helps.

As above i bought a different brand from Selco for around £40, guess most builders merchants will offer a cheaper alternative that is most likely just as good.