Loft insulation

[Davey]

Hello,

The recent cold weather has made me want to top up the loft insulation. The existing insulation is 100mm laid between the joists and I’m looking to lay another 170mm across the joists.

I want to keep as much heat in as possible but I’m concerned about the possibility of condensation.

The soffits are not vented. Can I push the new insulation into the soffits or do I need to leave a gap? If so, how much?

Thank you

 

[Doggit]

It's going to depend on how much ventilation you have in the loft. As the sofitss are normally outside of the walls, insulating them isn't an issue. In adding more insulation, you're going to be cutting down on the condensation going into the loft, but you still want ventilation of some sorts, Have you got a breathable membrane under the tiles, felt, or nothing at all (in which case no problem); are there any vents in the tiles.

 

[Ian H]

There are some tray things you can fix under the rafters to maintain an air gap between the felt and insulation.