Natural insulation for lost attics?

[Christophe]

I would like to quickly improve the insulation of small attics lost. There is 30m² about. I want a R meeting the RT2005 is about 25 cm with a lambda 0.04. The roof is made of cellular concrete, the 2 thermal resistances will therefore add up.

Obviously I will choose a green materials. At availability level in the region there are 3 possible choices:

- hemp panel to cut: about 30 € HT the m²
- bulk cellulose (bag): about 12 € HT the m²
- vermiculite / perlite: about 35 € HT the m²

Obviously my choice is currently on cellulose (especially that it is a waste) but I'm afraid for 2-3 things:

- laying (a flocking done without a machine will probably be unequal)
- the behavior in time (especially in comparison with other 2)
- Rodent held (we did a lot everywhere despite the good job of Leo).

So if it's all over again in 5 years to take the pearlite that will probably take longer than the house ... no?

Edit, result, we opted for wadding and hemp: isolate-des-roof-laying-de-panels de-hemp and cellulose-t4708.html

[pef]

If you had not had a mouse I would have told you straw boots ...
But hey, it'll be the fiesta for them.

[Christophe]

Is the insulation straw treated like cellulose (flame retardant, water repellent and "ratifuge" )?

And what is its thermal coefficient?

I don't trust the straw "in the open" since it is hygrophilic ...

[jonule]

Hello,
I put all the details of laying straw bales in the rules of the art on the subject: "natural insulators: what to choose?" at this address :
https://www.econologie.com/forums/les-isolants-que-choisir-t4325-10.html

of the previously treated subject, where we can see that the straw boot is the cheapest material at last in the boot, the time that indus put it in roll or panel?

otherwise I already said on the old post (old 2 weeks only) that mice preferred polystyrene and glass wool because it is not as compact as the straw bale!
who + is, the layer of lime on the straw boot, simple to apply, repels the rodents that's why they put in the stables and tombs.

In any case, if there is wheat or other beside an isolated installation, rodents will settle there whether polystyrene, glass wool or hemp, etc ...

think well when you put an insulation, the finish! it is she who is expensive, on the straw a coating earth, straw-clay or lime is easily achievable, see a guy from my corner who offers training and has superb demo instalaltions (see photos of the achievements he did) :
http://www.trakterre.fr/


if you want, Christophe, on the internet you will even find a Fire Resistance Report delivered by the CSTB.

In fact, following my discussions with my straw supplier, a farmer, he can indeed adjust his baler at 30cm thick!

its thermal coefficient is given by its compression ratio, adjustable as you imagine, and during the compression stage you can even add other products, suddenly mixed with straw.

while waiting to find it all done in Bricodepot, while waiting for the farmer it is once again the least expensive!
finally everyone sees as he wants of course ...

for the hydrophilic straw, the layer of lime protects it so normally you do not need a vapor barrier, because the air gap between the roof and the underside is enough to ventilate / dry the insulation, but as I want the installation is sure and lasts several decades, I put a brakes rain vapor barrier.
The straw boot is very breathable, so it evacuates steam perfectly.

after, arrange it against the straw or leave 3 cm between the straw coated with lime, must see, a leroymerlin insulation arises against the isoalnt, it seems that it avoided the insulation to be cooled ...



finally here is christophe, a cheap solution: straw boots on the ground, covered with a layer of lime!
you have to lay them out, coat them, wait for them to dry, then turn them around, re-coat them.
The advantage on the floor of the attic: you can still walk on it!

[Bmag]

I chose cellulose despite the inhabitants

But she is in closed coffers.
Otherwise, I have a friend who used it in his attic and covered it with a thin layer of moistened lime to prevent its dispersion in high winds and keep rodents away.
Bmag

[bpval]

Bonjour Christophe

At my neighbor, GDF intervened in emergency the other day, because rodents nibbling on the "polyethy" tube of the meter.
She has a labrador ... but no cat ...

You can imagine what he can do with their teeth ...

Cats I am, but I especially found that the best hunters in this case are females and especially since they had litters ...

So put the straw and if your LEO is not a cat, adopt one, she makes small (once, it's Belgian) and you're quiet for at least 12 years.


Hello

[Christophe]

You have beautiful eyes you know !

More seriously, the cellulose sold is not supposed to be treated (boron salt) against rodents? For the wind no problem on the other hand the attic is "closed" ...

[Christophe]

So put the straw and if your LEO is not a cat, adopt one, she makes small (once, it's Belgian) and you're quiet for at least 12 years.

Thank you for the veto lesson

Ben to make small ca it will be hard ... it's more a real male if you see what I mean ...

Anyway, the attic is so "lost" that there is no access ...

After that there's still rat death or traps, but ... I would have preferred to take indigestible cellulose ...

[Bmag]

You have beautiful eyes you know !

More seriously, the cellulose sold is not supposed to be treated (boron salt) against rodents? For the wind no problem on the other hand the attic is "closed" ...

Yes, it is treated with boron salt and supposedly repellent for rodents. That said, rodents do not like bulk insulation in general, because it is impossible to dig stable galleries, except to use minor techniques that rodents do not know.
Bmag

Christophe, did you still modify my photo link or did it work all alone, this time?

[Christophe]

Ok that's what Christine just told me too. I think we will do a mix history to test the 2 type of insulation (see 3) with a large majority on cellulose.

For the image, nan ca had worked ... except that you had forgotten the tag [IMG], the next time it would be good