Loft insulation thoughts / advice (Strange loft)

[matt_fsr]

So I've just moved into a new house, and having popped up into the loft, I've found there's literally no insulation up there at all. (Old house, late 1800's I'd guess)

Thing is, the floor of the loft is fully boarded, because the underneath of these boards is the ceiling of the room below, and there's no joists in the loft because they're "upside down" jutting down into the room ceiling space - if that makes sense.

I want to get the loft space insulated, but I've never come across an area like this before - Seems like standard options don't quite apply here.

Has anyone ever insulated a loft like this? I'm open to suggestions, currently toying with the idea of putting a closed-cell foam self adhesive insulation layer on the floor, but I want to use the loft for storage as well so I'm thinking if I did that, I'd need to raise the floor level up a bit, or the foam would eventually get ripped and trashed.

Thoughts?

 

[robj20]

Go for PIR board, you can then put chip board on top of that and you have your useable space again.
140mm PIR board is as good as the recommended standard loft insulation but it obviously comes at a price.

 

[jellybeard999]

Not sure on your ceiling height, decor or whether the building is period/listed or anything, but you could insulate and reboard the ceiling in the rooms below.

 

[eviled]

very pricey to by 140mm PIR slabs up there

cheaper to use loft stilts and 300mm of loft rolls

 

[matt_fsr]

Go for PIR board, you can then put chip board on top of that and you have your useable space again.
140mm PIR board is as good as the recommended standard loft insulation but it obviously comes at a price.

Seems to make sense so far, don't mind the cost too much it's not a huge loft, and the payback will be worth it. Just trying to work out how to put the chipboard on top of it safely at the moment.

Not sure on your ceiling height, decor or whether the building is period/listed or anything, but you could insulate and reboard the ceiling in the rooms below.

Not listed, but I don't really want to mess around with the ceiling structure below, I quite like the look of it. The loft space isn't tall enough to be usable as a room, but we will use it fairly often for storage.

 

[eviled]

the chipboard can just rest on PIR without any issues

the issue will be how you'll get the PIR up there!

 

[robj20]

the chipboard can just rest on PIR without any issues

the issue will be how you'll get the PIR up there!

You cut it into bits that fit, then use foil tape and expanding foam to put it back together.

 

[Maccapacca]

Watch your loft hatch size. PIR boards won't go up, loft roll is wound tight to get it in. Same with boarding it out, you'll rip down ply or chipboard to get it up.

 

[matt_fsr]

the chipboard can just rest on PIR without any issues
the issue will be how you'll get the PIR up there!

Wouldn't that make it likely to move around a bit? Due to the age of the house, the insulation might not make a perfect fit out to the outside edge of the loft.... which probably isn't square either.

Watch your loft hatch size. PIR boards won't go up, loft roll is wound tight to get it in. Same with boarding it out, you'll rip down ply or chipboard to get it up.

Good point, it's not a big hatch and it has a fitted ladder which further restricts object size access. I'm thinking of enlarging it, which might be a job to do first.

There's also possible / probable air gaps between the tongue and groove boards, given how old and dried out they now are. So I'm wondering whether something like a bottom layer of self adhesive closed-cell foam material would be a way to start out? Thoughts?

Loft area is going to be roughly 20 square metres.

 

[robj20]

Watch your loft hatch size. PIR boards won't go up, loft roll is wound tight to get it in. Same with boarding it out, you'll rip down ply or chipboard to get it up.

That's why they do loft flooring chipboard has a deep tongue and groove on it and fits through hatches.

 

[alexakasloth]

Not listed, but I don't really want to mess around with the ceiling structure below, I quite like the look of it. The loft space isn't tall enough to be usable as a room, but we will use it fairly often for storage.

Loft legs, boards and insulation in between.

 

[JBuk]

Going from what you describe, the ceiling of the room below the loft does not have a proper ceiling?