Building a garden office

[simonh64]

Hi,
Looking for some advice with regards to building a garden office. I intend to build a 12’ by 11’ structure, with 3x2 framing, clad with cedar shingles. I will be pouring a concrete base for this, and so was wondering if 3x2 beams would be fine for floor joists. My gut instinct says that would be fine, but I would like some advice from people who know what they are doing. Also, would 3x2 be suitable for roof joists? I am thinking of having a polyroof type thing and wondered whether 3x2 covered by 18mm exterior grade ply would make a suitable base for this. Another thing is insulation, would 50mm Kingspan/Celotex provide a good level of insulation for such a building all round, or should different thicknesses be used for ceilings floors etc?
Any advice gratefully accepted and many thanks in advance.

 

[big-all]

i used 3x2 at 2ft or more accurately 1ft11" centers floor joists wall all the same roof 4ft max 2ft minimum outside skin 12x10ft
http://s21.photobucket.com/albums/b270/bigall2005/?action=view&current=e1e47346.pbw
18mm ply floors and roof

 

[simonh64]

Thanks for the reply, looks like that will do then. Tally Ho

 

[big-all]

mind and place felt/dpm between concrete and wood
ideally there will be an inch or two between concrete and felt like a slab or brick so any water driven underneath by the wind or floods will have little or no effect on the wood
you need a ventilated space between the builders membrane behind the outside cladding and the insulation

are you aware off the planning regulations for sheds ??

 

[simonh64]

Yeah, in the process of putting application together at the moment. I live in a conservation area so have some experience of dealing with local planning types. Thanks for the heads up anyway.