Insulating by combining reflective insulation + cellulose-based insulation

[Garald]

Yet another episode of the insulation saga - perhaps the last one?

 

As some of you remember, I am renovating a (hitherto uninsulated) house from around 1930 in the Paris area.  On the south side, I have a bit of space, and I also very much have a need for as much sound insulation as I can get (busy street); thus, unsurprisingly, we are going to use 145cm of cellulose-based insulation (BioFib Trio) - counting an air layer and an anti-fire barrier, we are talking about 18cm or so.

 

On the north (courtyard) side, however, I don't have that much place to play with. My architect considered polyiso (PIR) for a while, but there is some contradictory information regarding its safety in case of fire.

 

Now my architect proposes the following solution for the north side: combine reflective insulation (as in, e.g., https://www.materiaux-naturels.fr/produit/1468-iso-lin-hpv-isolant-mince-reflecteur , which gives R=3.25) and about 45mm of BioFib Trio. In total, the insulation provided is well above the norms (R>=3.8). 

 

What is the catch? 

 

 

[SteamyTea]

4 hours ago, Garald said:

What is the catch? 

Unknown long term performance.

[Garald]

2 hours ago, SteamyTea said:

Unknown long term performance.

Anything I should be particularly concerned by?

[SteamyTea]

4 minutes ago, Garald said:

Anything I should be particularly concerned by?

I had a quick websearch and just hit the academic paywall, but there does seem to be a fair amount of longitudinal studies about it.

Seems dirt and loss of refelectivity is the issue.

You can use your university login to read that stuff, and anything interesting you can post up.

[Garald]

12 minutes ago, SteamyTea said:

I had a quick websearch and just hit the academic paywall, but there does seem to be a fair amount of longitudinal studies about it.

Seems dirt and loss of refelectivity is the issue.

You can use your university login to read that stuff, and anything interesting you can post up.

Send me a link or two to get started?

[SteamyTea]

1 minute ago, Garald said:

Send me a link or two to get started?

https://www.sciencedirect.com/science/article/abs/pii/S0378778818315986

 

 

[Garald]

Thanks!

[Garald]

I'll just include some links to the insulation materials the architect is proposing, for ease of reference. The price is surprisingly sane - around 20 eur/m^2.

 

https://www.ati-isol.com/gammes/isolants-respirant-hpv

https://www.materiaux-naturels.fr/produit/1468-iso-lin-hpv-isolant-mince-reflecteur

https://www.isolation-itr.com/non-classe/thermo-laine-lin-2.html

http://www.isolantmince-discount.com/fr/isolant-mince/56-isolant-multicouche-m17-pro-lin.html

https://www.winco-tech.com/fr/produit/skytech-pro-xl-toiture-isolant/

 

The only one to have a (very) good fire rating is the last one, which, on the other hand, seems to involve fibreglass, whereas the others contain no synthetic fibres. Same dilemma as usual.