I'm planning a large shed next year in SE QLD. (humid). It should come with vermin seal, 4 whirly birds and a lot of doors.
The slab is to have a moisture barrier under it.
Once I finally get my dream shed erected, it should have insulation foil on the ceiling and walls.
I'm not exactly sure what insulation this is but that is what I asked for. Then inside that, my idea was to build a timber frame.
Some people have suggested I could screw the sheet material into the steel wall purlins to save money. Maybe. I'm not sure. If not, then it's back to plan A. Which is to build a 70mm wide frame in-between the portal frames. It's not structural so I figure 70mm wide is fine.
I haven't decided how high to make this frame but probably 2.7m or 3m high. Currently I am leaning towards 15mm melamine sheets, if I can find the Moisture Resistant type. Although yellow tongue seems to be a popular alternative. The wall is 4m high, approx.
Questions:
* I can use T2 pine frame timber. However I was also thinking that I would lay a damp course under this frame to isolate it from the concrete. (Damp courses in QLD seem to come with metal in them as dual purpose termite barriers but I think I'd still use T2 timber anyway.) The idea of the damp course being, that if the floor does get wet then either it wont soak into the timber or if it does, the timber would dry faster being isolated from the concrete. Is that good thinking or am I locking the ambient moisture (e.g. condensation) into the timber floor plate?
* For both sound and thermal reasons, my plan is to put some sort of insulation in this frame. I am thinking 'wool' roll style. I assume there will be some small gap between the foil and the frame. But I don't really know any specifics. What sort of gap or other issues might I run into if I put the 'wool' insulation against the foil insulation? Of course if there is a gap there, I could use builders wrap to keep the wool installation inside the frame and maintain some sort of gap by the foil.
At the rear of the shed is going to be an office. The wife wants a lot of storage and so I am thinking of a mezzanine over the office. I am calling it a mezzanine because that sounds fancy. It will really just be a giant shelf. Especially if anyone from council asks. I haven't figured out a stairway for that. None the less, since people may walk on it and since it could end up with a fair bit of mass on it, I'll build that to structural flooring standards. Knowing me I'll over engineer it as usual. This is where my idea of 70 x 35 framing sort of weakens. I feel I need 90 x 45 framing for the office to hold up the floor above. So that part will be 90 wide structural frame and the rest 70 wide frame. Awkward.
Any problems I haven't considered?
I'm trying to estimate costs.