I know this has been covered a number of times before but a quick search didnt give me the answer I need.

I need to add insulation to the loft in my house which is quite old – 1840s.

My concerns are:

the ceiling joists are very thin – is there a minimum thickness to allow a person to walk on them – have used some old floorboards previously but didn't feel safe

the gap between the roof and loft has been sealed – is it simply a case of cutting with a stanley knife, how big should the gap be and would it be ok to just cut the back of the house? (front is hit by sw winds coming off irish sea)

would most people recommend clearing out old insulation material first?

what do people think of this method?: http://greenoldhouse.wordpress.com/2007/12/31/installation-of-loft-insulation-first-instalment/

Any thoughts most appreciated 🙂

mate, dont bother clearing the old stuff out, as long as its pretty even, just wack the new stuff down as thick as you can.

chheers – thats how cold i am!

Don't know the ceiling heights you have, but the other approach would be to insulate from below, screw Kingspan up through your existing ceiling to the joists, with battens, then add another plaster ceiling below that. You'd be bound to get a better result from the wiring and ventilation of roof void point of view too.