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It's that time of year, so it's my turn to ask loft insulation questions.
a) what is this?
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...it's _not_ asbestos, according to the environmental testing company I sent a clump of it to (Northstar Environmental, a send-sample-in-post service who then sent me a report).
It's some sort of loose fill, it feels and looks a bit like something between wool and paper, and I've got a loft full of it. But it's only full to about 10mm. We've recently moved into this 1930s house and as well as fitting double glazing we're hoping to better insulate the loft so we're wasting as little energy as possible.
b) is it any good? It seems to be quite light and fluffy. It's filled about 10mm deep and it looks like we'll need to add about another 15mm of insulation depth. I'm happy to order stilts and boards and put down new insulation, I'm just wondering whether it's worth going through the ballache of removing all this old stuff and replacing it.
I'd appreciate any advice the mountain biking home insulating collective can offer!
Newspaper. Our 1953 council house has it
I've got an area like that, in my case it's cavity wall insulation that has overflowed out of the top of the cavity I think.
I'm not entirely sure what it is.. but it looks like it is long past best and should be removed before putting new stuff down.
It looks pretty loose, maybe an industrial hoover or something to suck it up?
10mm deep and it looks like we’ll need to add about another 15mm of insulation depth
I think you’ve either typo’s or got mm and cm mixed.
I’m gonna assume you mean 100mm and you think you need to add 150mm.
Well you should be aiming for 270mm overall of quality insulation. That’s usually 100mm between rafters and 170mm above.
There’s no particular reason to remove the existing, I just wouldn’t consider it quality insulation so I’d be aiming to add 270mm on top.
Of course, if you wish to build storage on top that may necessitate removing the existing to replace with new to prevent too much height gain.
One area to be wary of is the eaves, where ventilation needs to be maintained. Because of this it may make sense to remove the existing in this area only to maximise the amount of quality insulation that can be fitted whilst minimising height and air flow blockage.
There’s no particular reason to remove the existing
I dunno about that... it looks like there's no insulation apart from the piles of congealed crap in the picture, exposing the ceilings of the upstairs rooms...
I'm not an expert but all that shit (whatever it is) needs to be removed before you think about adding insulation.
Whatever it is/was it looks like it got damp and clagged up.
I like your plate
Cellulose insulation, I think... https://en.wikipedia.org/wiki/Cellulose_insulation
Current stuff is fire and insect-resistant, but yours might be a century old so who knows?
It can hold moisture if you have a leak, whereas more modern insulation dries out more quickly
Do you have cavity walls? Take a peek because that's a normal use
Yeah I'd get shot of that, it's not doing anything, rubble sacks and a Henry hoover. You may be able to hire an industrial hoover and suck it all out.
Incidentally I bought an extension tube for my Henry so can now hoover five metres from the base, perfect for lofts. Cost a tenner
IIRC 270mm is UK building standards minimum, you could go for far more as per the recent thread. Scandi standards are 400 I think
Once your loft is done, go round looking for draughts, check behind skirting etc. There's always air getting in somewhere. I plugged all mine with wool or plastic fleece. Think incremental gains, everything adds up. Can you insulate under the floor?
Bear in mind diminishing returns. IE 200mm does not give twice as much reduction in heat loss as 100mm. Go past 270mm and there will be very little difference.
https://www.thegreenage.co.uk/what-is-the-recommended-thickness-of-loft-insulation/
Excellent, thank you! (and llama for the classic STW answer)
And @goldfish24, yes I did mix up units, sorry. It's currently about 100mm deep, and I think I'm going to have to remove it and replace it if I want a total of 270mm.
It's definitely just laid / blown / scattered on top of the boards of the ceiling below. While clearing it up I'm picking up lots of lumps of plaster that have been squidged through between the slats. I'd rather not get into replacing all the ceilings of the upstairs of the house with fresh plasterboard, but I'm aware this is going to be a potential hassle if I do need to. Is this the sort of situation you'd put some sort of retaining layer in before fresh insulation?
It doesn't have a pungent herbal aroma, does it?
Sadly not - this volume of it would be worth more than the house, if so!
We had that cellulose stuff in our old bungalow - laid when they were built in the 60s. Didn't fancy the mess / bags of landfill trying to remove it so just laid two layers of insulation on top (one at 90 degrees to the other). Any subsequent jobs requiring delving into the insulation weren't very pleasant, but the loose stuff did generally stay in place OK. If you have a small area then I'd get shut, but it seemed a bit pointless with the quantity we had.