Insulation

[stevenrafferty]

I was looking at increasing the insulation within my attic space - the existing looks as though it may be the original stuff.

However, our up stairs rooms are partly within the roof void, so have partly commbed ceilings and I noticed that there is no insulation between the underside of the roof and the lathe of the commb.

Can I install insulation within this area? I was worried that there may be implications with lack of ventilation?

The gap is only 4 or 5 inches, so it wouldn't fit a very thick piece of insulation but I was thinking of something rigid, possibly pollestryrene?

Any thoughts?

 

[oilman]

Sounds like you have an oldish house, like ours. I put insulation over the ceiling, and between the rafters where I could get at them. I've since had sleepless nights worrying about the tales of rotting and condensation, but no sign after 20 years. However, on the part that's along the roof line, I couldn't get insulation down it. Just as well really, there's rafters and laths and not much air movement. I think it's best to leave it vacant as there's nothing to stop moisture getting to the space, and condensation needs moving air to clear it.

 

[masona]

I've since had sleepless nights worrying about the tales of rotting and condensation, but no sign after 20 years.

Have to agreed, I have seen a couple of condensation rotting in my time but it is very very rare. I have then put in a extra ventilation, the problem seems to dried it out.
stevenrafferty,
Best to use rockwool slab insulation and if cut right, it will hold on it own between the rafters. Make sure you leave a gap behind approximately 50mm and 50mm on the bottom and top row to allow circulation of air-flow.