Are batttens and air gap needed for breathable membrane for a timber framed man shed

J

j-o-n-n-o

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Hello,

This is my first post so I hope it makes sense. Thanks in advance for your responses.

Ok so I am in the process of building a 6mx2.4m half shed half summer house. Stud walls are up EPDM roof on.
The next step is the cladding, I am aware of how I should clad i.e.

Exterior cladding
Battens
Breathable membrane
Ply
Studwork filled with insulation
Damp proof membrane (plastic)
interior cladding/plasterboard etc.


My issue is I've already installed all my windows and doors and only allowed for the cladding depth of 20mm so won't have space for the batons.

My question is should I just put the breathable membrane on the outside of the studwork and clad straight on to that? I know there won't be an air gap but could this work?

Or

Clad straight onto the studwork and then fix battens to the inside up to the back of the cladding and up to the studwork and staple a breathable membrane on to the battens to create an air gap?

Or

Just wing it not use a breathable membrane insulate with kingspan and leave an air gap on the exterior cladding side?

(See the very poorly drawn attachment below)

I do hope that makes sense any advice would be very much appreciated.

Thanks,

John
 
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In a choice between the two, the first one.

But you have not got any sheathing boards externally. So what is to stop the whole frame twisting?

Installing the windows does not stop you extending the cladding outwards and having a sheathing board and an air gap.
 
Thanks for your reply Woody.

When I started I was just going to make a normal shed but thought if I'm doing it I may as well future proof it incase I want to turn it into a office, games room etc.

I suppose I thought the cladding would hold it together like in a normal shed. Do you not think this would stop it twisting? It is wobbly with just the frame up, felt sea sick after doing the roof.


I stood the window frames out 20mm so I could clad up to them so there was no cut ends of the cladding showing(See photo below). How would you suggest finishing round the frames if I batten and sheathing board it?

I am leaning towards doing it right what do most people use for sheathing? Ply or Osb? And what thickness could I get away with?

Thanks,

John
 
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Here is s quick detail about how to finish cladding at the window sides. But you also need to know how to install the drips above the frame and below the cill.

You need 11mm OSB, ply or cement board to sheath the frame though. The cladding won't stop it moving or twisting.

Have a read up on timber frame panels and construction.
 
Thanks for the drawing and info very much appreciated. That makes sense now thanks.

I've just ordered my Tyvek, battens and 12mm ply and insect mesh so I am going to do it right with air gap and battens. I've just got a couple more questions;


Can I fix the battens just to the ply or do I need to line them up with the studs? (would be easier to not fix to studs as my spacing are a bit all over the shop)


As I mentioned earlier it is not sheathed yet am planning to do it next weekend. I have all the stud walls up, roof on, Windows and French doors in. The structure is still wobbly and when it is sheathed this should hopefully stop it flexing.
I've just put a spirit level on it and the whole structure is leaning forward maybe 1-2" it was straight when I put it up but I'm guessing the weight of all the windows and doors is pulling it forward maybe?
I'm a bit worried as it is leaning so much. If I attach some 2x4's to the front and push it back over and then sheath it do you think this will straighten it up and hold it straight once the 2x4's are removed Should I go slightly past straight in case it springs back?


Sorry for all the questions just got slightly panicked when I saw it was leaning.

Thanks so much for your advice already and any replies to the above.


(a slightly worried and nervous) John
 
If it's leaning get it shored up ASAP.
I don't want to panic you but you don't want an expensive pile of wood. Not sure how heavy it is but think what happens if it fails when you're underneath.
Basically push it to level and get someone to nail diagonal braces on all 4 sides. Don't remove them until you are about to sheath the side, and only remove one at a time.
It should be strong enough at all times so that pushing it doesn't cause it to move appreciably. Use common sense.
Good luck!
 
Thanks for your quick reply John very much appreciated. Will get on to it ASAP.

Do you think 12mm ply for the sheating will be good enough to hold it straight?
 
Nail the battens into the studs, not just into the ply.

The roof structure should be used to keep the walls plumb. Start on one elevation, plumb that, then that will give you two vertical corners for the adjacent two sides, and then plumb the final elevation. Once the sides are braced by the roof, it all acts as one and won't move.
 
Have just managed to get a few braces on but am struggling a bit on my own to pull it over and fix it at the same time. Any tips on shoving the frame back to get it straight?

Woody the roof is already on, I suppose it's quite a big structure 6X2.5m no internal walls up yet and I've got a 2.5m patio door which won't help much.

The floor is still level, all walls seem plum with each other it's just all leaning forward. Am hoping once I've got some help I'll be able to get it pushed right over and sheated and all will be good but?

Why do you think it is leaning like this? apart from my dodgy workmanship..

Thanks again!
 
You have no anti racking you need to put some osb/ply(or use wire or banding) on the inside or outside of the frame. You'll have to shove the frame back square as the weight of the roof will be have moved everything.

You could drape the membrane between your stud work to allow some air movement, still not the best long term solution though.
 
If you really can't get help from the neighbours or anyone, you could prop it with spare wood before you brace.
But stopping it going further is the important thing, even if you can't brace it upright and true just bash the braces on at whatever angle it's at now. At least it's going no further then, and you can find someone to help in the medium term to get it how It should be.
 
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