Basic loft use

[AnonymousImport]

I want to use my loft for a small office, with limited weight use. The firm that have just insulated the loft advised using 2"x 2" baton across the rafters and then 8'x 2' tongue & groove loft boards parallel with the rafters.
Would this be safe/ok?

 

[AnonymousImport]

you dont say if it is a trussed roof or traditional roof but 2" by 2" is no good anyway,you want joist hangers fastened to the wall so the new joists are not touching the original ones and make a completely new floor, you might as well do it right in the first place in case you ever want to turn it into a room or put something heavier up there plus youre going to be walking about on it anyway, floor joists are 9" by 2"

 

[AnonymousImport]

floor joists are many sizes from 4" x 2" to 12" x 3" - depends on the load, the span and the grade of timber used. you may require a larger joists, but more likely smaller ones. for example a 3.5 meter span needs 7" x 2" joists (with struts at the mid pint) at 400mm spacing using C-16 timber (SC3) to support a floor and the ceiling below it.

your building control office or the government have span tables you can use. They are on line:- http://www.safety.odpm.gov.uk/bregs/brads.htm
Table A1 for floors (standard timber).

if your wall plates stop level with your ceiling, hangers may be difficult to use, you might need to pack your joists to avoid touching the ceiling. you will need to use 3/4 height strutting to avoid the joists twisting if they are not in hangers