AIBU to not take the offer of free insulation ...

[MmeLindor]

in favour of putting in a more ecologically friendly alternative?

The guy who was here this morning was totally taken aback when I asked what exactly he would be filling my cavity walls and loft with. 'No one has ever asked that before, they are just glad it is free'.

DH is German and we have only recently moved back to UK. Over there people are moving away from mineral wool/glass fibre insulation and putting in natural alternatives.

I am not a lentil-weavery person but I do think that not allowing the walls to breathe is perhaps not conductive to a pleasant room climate -- that sounded really lentil-weavery, didn't it? It is a big thing in Germany, the room climate.

My parents have cavity wall insulation and I find their house unbearably stuffy. Which may of course be due to somehting else entirely.

I am concerned that we would be storing stuff up in the loft that is filled insulation that needs gloves and facemasks to be worn when fitting because of the irritation caused by the glass fibres.

Anyway, current plan would be to put down Thermofleece and floor the loft (we would need to floor the loft anyway cause we need the space for storage, so it is really just the extra cost of the Thermofleece or something similar (I think about £500)

[Flatbread]

Totally agree with you. No point being penny wise and regretting it later.

[PigletJohn]

yes

Cavity wall insulation does not make houses stuffy. Lack of ventilaton does that.

The modern loft quilts are treated to prevent them shedding loose fibres, which I think is great as the old stuff used to make me cough badly. I still use a mask and gloves in anyone else's loft because it is probably dirty and dusty.

But if you have the money to pay for something else, that's fine with me. You will take a bit of the load off the taxpayer.

If you want to apply 250mm depth of insulation (I see that would cost £25 per sq metre in sheeps wool) and board on top, you will either need deep counterbattens, or you can use a kingspan or celotext type product with the flooring laid over that. It is rigid so will support the flooring.

BTW, how do they prevent moths in the sheeps wool?

[MmeLindor]

Well, we don't actually have the money in that we have tons to do to the house, and if we do this, then we won't be able to afford something else like a wine fridge

But I am concerned that we are going for the free option cause it is free, and not because it is what I would have chosen if I were making the decision based on what we want.

[Flatbread]

A wine fridge is pointless. We got one from Amazon and are on the point of returning it as the whites don't get cold enough.

Good insulation, otoh, makes allthe difference.

I am going to see if I can find a link to cavity insulation and its impact. I read some guy who made pretty salient points. Just like piglet John, but on the other side of the fence on this issue.

As an anecdote, we have some stone walls that had plasterboard and cavity. Presumably to insulate. Builder was adamant that we take the plaster board off. And he was right, because the beams had rotted away as there was moisture trapped between the wall and the plasterboard.

In old houses (presumably that is what you have), figuring out the right kind of insulation can be a real pain.

[MmeLindor]

puts fingers in ears not listening to anyone dissing my wine fridge. Have already been put to rights about the GCH plans.

That is what DH is worried about - damp getting into the cavity space. It is a 40yo brick built house, so not that old.

I reckon that the new windows and heating will make a much larger difference than cavity wall insulation.

[Flatbread]

Lol, MmeLindor

Here is the link on cavity wall insulation. PigletJohn will probably be able to provide a balanced view to help you decide

www.askjeff.co.uk/cavity.html

[PigletJohn]

I suppose the world needs a few Luddites

There is no much to disagree with in that man's writing that I haven't got the energy.

Still, he's got a book to sell.

[PigletJohn]

Here's an example of a misleading claim

"The manufacturers and installers claim that the material is water-repellant, and that it cannot allow rainwater to penetrate across the cavity. However, my own researches show that - far from being waterproof - it can soak up water like blotting paper. Samples sent to me by readers have been found to hold a startling 243 per cent moisture - ie nearly two and a half times their own weight in water."

I have handled the blown fibre. It is treated to repel water. If you take a handful of it, and dip it in a bucket of water, as soon as you take it out, the water simply runs off. It does not stay "wet" in the way that a handful of cotton wool stays wet. Water does not track across it by capillary action.

But now think how much a handful of uncompressed cotton wool, or fluffed-up mineral fibre. or down from a duvet, weighs. Approximately nothing. If was possible, in some way that I haven't seen, to dampen it and make it hold (approximately nothing x 2.43) how much water would that be? When I have taken mineral wool out during building work, it has been dry as dust, and so has the brick dust from the building work.

If you have a wall in bad condition, with cracked and missing pointing, then, yes, your faulty wall will not be weathertight. The cure for this is not to continue pouring expensive energy out of the walls into your garden, it is to repair the wall.

[Pendeen]

Would agree with PigletJohn...

Blown Rockwool for the cavities and Thermafleece for the loft.

John also makes a good point about the condition of your walls. Just ask the installer if he has heard of / followed the advice in BRE Good Building Guide 44 - P 1 & 2.

If he looks blank, then don't let him near your cavities! :)

[MmeLindor]

Well, that is part of the problem, tbh. He was so short and disinterested in my questions because he is so busy at the moment that he doesn't actually need the job here.

I'd rather get someone in to do a decent job and pay for it. I am sure there are varying qualities of the product that they use. And I presume that the free service is not likely to be using top of the range stuff.

PigletJohn - perhaps that would explain the differences in your experience and some of the readers of his book/website.

[PigletJohn]

incidentally, I live in a coastal area, and the West side of my house is clad in slates (upper floors) and shiplap (ground floor) to keep the weather off.

In storms the water comes off it like a waterfall.

That's the kind of wall I think they don't recommend filling the cavity, if expposed brick. I have seen a map somewhere or areas with driving rain, I think West side of Scotland, Highlands and Islands mostly.

My other walls are brick and dense block, blown fibre, excellent condition. If I could find my comparative gas records, I could tell you how many £hundreds per year it saved, but I immediately noticed how much warmer the house stayed, e.g. if i came home at lunchtime, and there are no cold parts of a room.

[MmeLindor]

I think we are decided on no cavity wall and we will go with our own guy for the roof space.

Thanks for your advice, PJ but both of us are not comfortable with the offer. I might go over for a trade fair in Munich later this year, where they show the latest technologies - the Germans tend to be a bit ahead of us in this area and I'd like to know what else is available.