Hello all.

This years project looks set to be a large shed at mums place.

I'll be building from scratch, as I want a challenge and to achieve
something better, more substantial and different from the usual stuff.

It'll be about 18' x 8', part potting shed, part summer house, with
covered veranda deck area. There's a CAD render of the design at
http://www.sbriggs.plus.com/shed14.jpg

I have a few questions for the collective wisdom of the group on
construction methods and materials.


The latest thinking on the base is to mount it on single brick pads (on
a large, existing concrete platform), then a 50x100 joist frame, T&G
floor, then the shed structure.

Wall & roof framing I'm thinking 25x75 sawn timber studs & rafters,
50x75 sill & head. Inside skinned with 6mm WBP ply, outside with VT&G
weatherboard. I'll put about 30mm of Celotex / Kingspan on the inside
face of the wall cavity. I'm debating the need to vent the remaining
cavity to the outside, I can easily have a 10mm hidden gap around the
framing at ground & eaves level, and over the roof ridge board. Is this
a good idea? Should I put a vapour barrier in there somewhere? If so,
what to use?

Timber treatment is another issue. While the floor joists will be
tanalised timber, I don't think my local timber yard has on-site
treatment plant, so everything else (weatherboarding, frame, floor etc)
will be untreated red or white wood. I could then paint or spray a
suitable preservative on, but would it really be worth shopping round
and getting the whole lot prevac treated (which adds about 20% to the
cost)?

Any other construction or material suggestions welcome.

Finally, this is grand excuse for compressor and nail gun purchase.
Probably the Axminster £100 compressor (2.5HP /25L /7cfm FAD) and 50mm
brad nailer. Are 18ga brads going to adequate for the cladding?


Cheers all,

--
Steve