Garage conversion

[TheMightyAtom]

I would like to convert our garage into a storeroom/office.

I am new to DIY and from reading on the web I understand the first thing to do is insulate the floor and then cover with a chipboard floor.
I hope someone can advice on the following:

- How far apart and what thickness should I make the floor joists?
- What would should I make the joists from?
- What is the correct insulation to use?
- Do I need a damp proof membrane on both sides (the side nearest the concrete slab and the side nearest the room)?

Thanks in advance for your help.

 

[theprinceofdarkness]

Damp can be stopped coming through the floor by a variety of techniques, a plastic sheet, such as Visquene or a water proof paint such as Syntheproof. This must be taken up the edge of the wall to a height greater the the floor. How water proof are the walls? will you insulate them? Unless the concrete is absolutely smooth, sharp bits might pierce the plastic sheet where the joists sit, so its best to put some additional sheet material at the joist positions (old plastic flooring/roofing felt).
Joist :- 4" X 2" at 16" centres, flooring:- P5 T & G chipboard
Frank