Loose lay insulation under a flat roof?

[Steve Jones]

Hi,

I need to get some insulation into the void under a flat roof.

The roof is 12x12ft and I can get access between the joists from one end.

I'm hopping that I can push loose-fill insulation in from the end using a home made tool of some sort.

Can anyone tell me if the approach stands reasonable chance of working or is the loose-fill likely to clog up before I manage to push it to the far end of the roof?

Also which insulation product is the most pushable?

Thanks, Steve.

[sm_jamieson]

Whatever you put in, if it is a soft sheet material, you need to "pull" it in rather than push it (e.g. rockwool etc). Fix a stick to the end of the material going in first, and use the stick to place it. You may need to use flexible rods I guess. You could put in some poly beads, and just push them in bit by bit. ensuring they do not clog. But make sure you are maintaining any required ventilation and vapour barriers etc. Simon.

[geraldthehamster]

I agree about the pulling. You used to be able to get lengths of rock- wool type insulation in red plastic covers - I'm sure you still can (B&Q?) - which would obviate the problem of disintegration.

Regards Richard

[Steve Jones]

Thanks for the replies.

Do you know of any bead or loose fibre products that I could be pushed in?

Steve.

[geraldthehamster]

Isn't cavity wall insulation blown in, when being retrofitted?

Regards Richard

[Phil L]

You can, using a sweeping brush, but you won't get it 12 feet, maybe if you took a section of ceiling down at the opposite side you might have a chance.

fibreglass. Rockwool is heavier but it's also more brittle because the strands are shorter and thicker than glass. polystyrene is a fire hazzard. Celotex type stuff is possible if you cut it into squares the width of the joists and push each one along until each run is filled but this is expensive