Loft insulation (eaves)

jblakes

Morning all, 

Finally got round to sorting the loft out. I've am wanting to put as much insulation down as possible as got given loads free, I know you are supposed to leave a gap in eaves. I have been looking at internal eave vents (manthorpe do one), the idea is stick this plastic product in then can load insulation upto it as you are not blocking the air flow.

My question is can't I just install a plastic sheet across the inner side of roof joists and then push the insulation upto this. That way i Could put 200/300mm, but know there is still and air gap that the insulation can't cover (unless the sheet breaks). Or am I over killing it and just make sure you leave a gap?

Kind regards
James

Bendy_House

In theory, yes, that would do the job.

Are your soffits properly ventilated - do they have grills or round vents in them? And, inside the roof space, the soffit void is nicely open to the loft?

If 'yes', then you can add what you say - a kind of baffle attached to the undersides of the joists that will keep the insulation from blocking the eaves gap, and will leave the soffit void fully open to the rafter spaces. Ie, when you fit this baffle/sheet - which only needs to come up the rafters a foot or so from the eaves - if you look down the void between the rafters, you should be able to see into the soffit void. Yes?

Then you can stuff yer insulation to the best depth.

I wouldn't take this sheet up any higher than is required, because you want that whole loft area to be free-flowing and, frankly, draughty

jblakes

Yeah all cleared, spent the weekend unblocking them.

Would you use a baffle thing or just run a plastic/rubber sheet on inside attached to joists to create a air gap?

Regards
James