LOFT CONVERSION "THE BASICS"

[frixster]

I'm hoping to convert my loft space into a extra bedroom in the near future, but before I go for planning permission I need some further information on the regs aspects.
Obviously I'm not asking for all the regs, just the basics such as:
1) What thickness does the load bearing joists (for the floor) have to be?
2) How far apart should the joists be?
3) How wide should the permanent stairs have to be?
4) Should the skylights be large enough to be used as a fire escape?
5) What thickness should the insulation be between the roof beams?

Also what would the best method of boarding up the roof, and also the floor (the materials?).

I consider myself to be very good at DIY (and my wife's family know it too!), so i'm going to do most myself, (i've already converted the old fire to combi and got rid of the expansion tanks in the roof).
But any structural work (such as any joist or roof alterations) I will leave to the pro's.
Just want a bit of pro knowledge before I call in the building insp!!

 

[Static]

1) Joist thickness will depend on distance between supports of the existing ceiling joists.
2) You will probably lie the new floor joists next to the existing ceiling joists, so whatever they are spaced at.
3) I believe its about 900mm minimum but dont think theres any strict rule
4) Velux (or simular) windows are the norm for use as fire escape exits
5) Thickness will depend on which manufacturer you use, you have to achieve a "U" value with the insulation