Underfelt for shed

[Deluks]

What's best to use behind featheredge boards that will be cladding a shed? The construction will be 2x4 floor and header plate.
3x2 studs/batten/featheredge.

I'd like to put something breathable between stud and batten. Reluctant to fork out for tyvek but would heavy duty brown kraft parcel wrapping paper do it? Or would I need to get proper building paper, which is about £35 a roll (isn't it?)


Will probably insulate and ply inside at a later date, but I don't wanna chuck money at this, just gonna wait and see what turns up on ebay (or in local skips )

 

[big-all]

i am still trying to sort this problem out with my shed for over a year now

simmilar 3x2" construstion with txg shiplap cladding
suggestions are building paper with kingspan ,loft insulation foam ect

the biggest problem is getting airflow to stop the timbers rotting

now i could quite happily fit 2" kingspan an inch away from the building paper and covered with 9mm ply

trouble is the inch gap will be fairly stagnent air because whatever direction you travel theres 3x2" timber ok may be 6ft long by 2ft wide but no air flow

in your case of course you may be ok as natural movement in the timber may give you enough gaps for airflow through the breathable builders membrane

 

[Deluks]

So what type of building paper did you use? (Cost?)

I thought this stuff was supposed to be breathable anyway, it's the same principle as a roof, just sideways. At least that's what I always thought.

If 'stagnant' air will be a problem I'll probably lay the paper horizontally across the studs, one on the bottom and one on top, and make some sort of foam wedge to keep the overlap slightly open. I've no immediate plan to insulate the roof, it will be 18mm osb, felted and then covered with cheap corried clear pvc for belt n braces weatherproofing.

For your airflow concerns I'd cut into the building paper. Make a few upside down T's in the paper, pull the triangular flaps inwards, reach through and stick some gaffa tape on the outside 'stem' of the inverted T. If you keep the edges apart by an inch or so this will create a pocket, which you can wedge open outwards with a bit of foam. If you can't picture it, think of an eyebrow dormer.

Or, cut holes in the kingspan and ply, then fit plastic or metal louvre vents on the plywood. I don't see how you will have much water ingress with shiplap anyway. I can only afford cheapo featherboard so it's more of an issue for me.

 

[big-all]

havent got that far yet thanks anyway
dont want to put anything on untill i am shure it wont ruin the workshop that ive built from scratch planned and designed myself costing best part of £1000

 

[Deluks]

Looks good (despite the mess ) You seem to have made the classic mistake of using the space before it's finished, meaning it'll never get finished!

Well if you find the perfect solution, let me know.