Attic insulation lost with cellulose wadding

[436937]

Hello to all.

I live in a house from 1989 that I just bought and I want to improve the insulation. So I start with the attic (not convertible) or about 90 m2.
There is already rock wool on about 20 cm. (She is therefore 20 years old, and it seems that there are a lot of thermal bridges!)

I spent a lot of time reading different posts on insulation, and there are a lot of reviews all as interesting as each other. It is a real gold mine and it allows to have several opinions. My choice will therefore go to loose cellulose wadding.

As far as I'm concerned, I brought in a Pro who advised me to leave the existing rock wool, and to lay it over the wadding. about 25 cm at a density of 25/30 kg m3.

I have not yet received his quote but it should be around 2200/2500 euros (he must make a living).

I thought I would do it myself (I'm quite a handyman) So I found a reseller of cotton wool. He offers me French-made wadding (Bellouate, lambda 0,039) packaged in 13 kg bags. He evaluated the quantity at 675 kilos, which will make me a total of 911 euros including tax. He does not make any discount on the price but he offers me the free loan of the carding machine over a weekend, and he is ready to take back the excess bags from me if there were too many.

This proposal seems interesting to me, and I therefore wonder if the price of the product seems to me honest, and if the quality does not seem too kind the first price of the material of insulation.

I would therefore like some informed opinions on this subject.

Then, according to some opinions it is better to put a steam brake, others not. I plan to place them, but only on damp rooms (wc, bathroom kitchen)

Are there enlightened opinions on the matter to pass judgment on my reflections?

Thank you.

[Woodcutter]

[...] As for me I brought in a Pro who advised me to leave the existing rock wool, and to lay over the cotton wool. about 25 cm at a density of 25/30 kg m3.

I have not yet received his quote but it should be around 2200/2500 euros (he must make a living).

Personally, I NEVER leave an old mineral insulator before putting a new plant in it, for various reasons, the main one being that they don't age at all in the same way, and also that their behavior in the face of steam is not the same at all ...

For the price, it's a bit expensive ... For this thickness, the material supplied should not exceed 2000 € TTC. Must now see the specific points (hatch, fire conduit, etc ...)
Furthermore, you have 25% tax credit on this, which will reduce your bill to around € 1500 including tax

[...] I thought of doing it myself (I am quite a handyman) So I found a reseller of cotton wool. He offers me French-made wadding (Bellouate, lambda 0,039) packaged in 13 kg bags. He evaluated the quantity at 675 kilos, which will make me a total of 911 euros including tax. He does not make any discount on the price but he offers me the free loan of the carding machine over a weekend, and he is ready to take back the excess bags from me if there were too many. [...]

For density, it is rather necessary to start on 30 kg / m3 and in addition add 10% in thickness for settlement.
We therefore obtain 756 kg for 90 m². That would make you € 1020 including tax.

For the advertised price (1.35 € / kg including VAT) it is quite competitive, but in the industry, everyone knows that Belloy (the boss of Bellouate) pulls on prices to make room for themselves in the sun ...

I tried his wadding and I do not like it too much because it is very, very loaded with boron salts (18% !!!) and suddenly, it makes a lot of dust and stings quite a nose ...

[...] Then, according to certain opinions it is better to put a vapor brake, others not. I plan to place them, but only on damp rooms (wc, bathroom kitchen)

Are there enlightened opinions on the matter to pass judgment on my reflections?

Thank you.

When you install 30 cm of cotton wool, you can do without a vapor barrier, even over damp rooms.

Below, the reflection deserves to be approached, but anyway, if you do not remove your LdR, I think that it is useless.

[lelenedenantes]

according to a craftsman seen yesterday, be careful with the cotton wool very "fashionable" at the moment

not to use in humid region

very chemical, volatile, and not ecological product ...

[Woodcutter]

according to a craftsman seen yesterday, be careful with the cotton wool very "fashionable" at the moment

not to use in humid region

very chemical, volatile, and not ecological product ...

What is this piece of crap?

Your craftsman in question, does he lay mineral wool?

[lelenedenantes]

he lays cotton wool, mineral wool too ...

[clasou]

Hello,
that's true when looking on wikipedia and looking for info on boron salt.
Suddenly the idea of ​​returning to the chevenotte came back at a gallop.
Because it is true when filling between the BC and the breeze block covered by the honeysuckle it may pass, but in the attic lost especially that it is volatile.
a + claude

[Woodcutter]

he lays cotton wool, mineral wool too ...

Did you read my comments on your other post?

[Woodcutter]

[...] but in the roofs lost especially that it is volatile.
a + claude

What is volatile?

[clasou]

Hello,
wadding, I opened a package, since I bought three, in fact I put at the beginning of the filling.
That I covered with the goat.
And it looks as nice as glass wool. to breathe of course.
a + claude

[Woodcutter]

It has nothing "volatile" ... Volatile is the property of a body to transform into vapor ...

On the other hand, when we brew it a lot, it creates a dust of vegetable fibers, which we must indeed not breathe too much. Cotton wool applicators wear masks.
Not at all the same level of danger as mineral fibers, however ...

In addition, not all wadding is of the same quality (dust, swelling, salt content).

I have already explained to you several times the differences between wadding and chenevotte ...