Hi V8eng
A few thoughts……. (As I live in Australia you will need to check your local regulations, they may differ)
If you use hollow Cement blocks the bond between them is not particularly good, solid concrete blocks are better. conventional clay bricks are better again. Depending on the length of the walls the engineer may require brick piers to support a single skin block wall. in the corners and every n metres, or if hollow block ask that the blocks be core filled with concrete, you will need insulation in addition. Single skin walls do tend to get damp.
Sometimes conventional double brickwork with a cavity that is unlikely to require piers does not cost that much more because only one tradesman is involved and without the extra labour of forming the piers the walls go up quickly. You can place foam insulation in the cavity between the bricks. (The brick ties are just pushed through a slot cut with a carving knife in the foam)
If you order your windows and doors ahead of time they can be bricked in. (Cover them in plastic) I don't know if they are available in the UK but in Australia you can get a solid core external door unit with a steel surround for bricking in, That will make it hard for the burglars.
If you are going to use a conventional roof with a central ridge you can order the trusses pre made, they should be easily manhandled by two people. they are simple to erect on the wall plates. (The wall plates have to be strapped down with hoop iron, make sure the straps are in the cavity so you don't see them. the underside of the rafters can be lined with plaster sheet and insulation. leaving the ceiling beam part of the truss visible.
Draft exclusion is often overlooked. The join between the brick walls and the ceiling must be trimmed, sealed and insulated. If you plan to have a roller door, they are quit difficult to draft proof and almost impossible to insulate.
Concrete does make the most rigid floor, with a couple of coats of paving paint to keep the dust down. Or use an insulating system. like John Hews Suggested.
I read an interesting article about Epoxy floors, in particular maintaining them. Epoxy does not stick to epoxy very well at all. This makes refinishing difficult the floor has to be ground back. I was going to do my workshop with epoxy, after reading the article I think I will just use paving paint.
Window's, As I write this I am sitting near a skylight in the attic. You can get them double glazed ours came from a company called Velux. **LINK** We have several in the house, they have never leaked and are highly recommended, I have no connection with the company. For a shed they may be a good alternative or additional to a window.
Regards
john
Edited By John McNamara on 03/02/2014 07:37:40