Insulation attic lost house adobe

[Eurus]

Hello everybody

new on the forum, I come to ask you for advice to improve the thermal insulation of my newly acquired house, in the North of the Rhône-Alpes region.
Problem: adobe house from the beginning of the last century, renovated in the early 80's. It has a ground floor, a floor and attic above.
A thin brick interior lining (which I will call briquette!) Is placed about 10 cm from the rammed earth. Between the two, a layer of air a priori essential for the "breathing" of the adobe.
The lost roof space is currently insulated with 10 cm of glass wool on the floor, but does not cover the gap between the briquette partition and the adobe wall. The roof is not joist, the air currents are numerous in these roof spaces. And this is where my pb comes in: I have the impression that the cold air rushes in with a malicious pleasure in this gap, and helps to seriously cool the walls of the two levels below.

I don't think I should block this space, risking not to let my earth walls breathe.

Also, maybe the solution is to isolate the crawlers? The walls will be able to breathe, but they will breathe a more temperate air, which will cool me less !!

If I am good until then, what mode of insulation do you recommend?

Thank you in advance for your wise advice

[laureilight]

it is already very clear that a thickness of 10 cm of glass wool is very insufficient. I think that at first you should review the insulation of your attic. I remain at your disposal for any other question.

[bham]

Hello Eurus.
It is indeed important to let the adobe breathe, but the installation of a “breathable” insulation cannot harm it.
I see two options for insulating the walls:
1- the blowing of cellulose wadding in this space between briquettes and adobe with, as a bonus, the installation of an interior vapor barrier, the principle being to have a sandwich of materials more and more permeable to the vapor of water from inside to outside. The installation of this vapor barrier implies, I think, the installation of a finish coating like placo, fermacell, while the interior finish already exists (I suppose). In addition this insulation makes lose the benefit of the thermal inertia of the walls.

2- Insulation from the outside, also possible by cellulose wadding blown into wall boxes; the advantage is that the thermal inertia of the rammed earth is kept for the interior heating and that the thermal bridges are eliminated. By cons vapor barrier necessary too I think (confirmation by Bucheron?).

For the insulation of the attic it goes without saying that it must be improved and ESPECIALLY obstruct this rammed space / briquettes at the attic level with a breathable material, lime, wooden board, ... lined with breathable insulation.

[Woodcutter]

So, houses like that, we see some of them passing through our construction sites ...

The first thing to do is to properly insulate the attic. 10 cm of LdV, especially if it is a little old, it is as if there was nothing at all.

Then, as said bham, we can very well isolate the intestice between briquette and wall with cellulose wadding: your rammed wall will have no disadvantage!
It is very easy to do if you have at least 10 cm with access from above.

In addition, during renovations and especially behind a rammed wall, we can do without a vapor barrier, knowing that in any case, the plaster + brick layer already has a certain capacity for regulating the diffusion of vapor.
In addition, if we can connect the wadding of the walls and that which will be installed in the attic, the total mass will work in concert for the regulation of humidity.

Unfortunately for inertia, we actually lose it.

Insulation from the outside: if the walls are really very thick, you have to be very careful, sometimes it's almost useless!
No vapor barrier in exterior insulation, the walls are sufficient for that.

You will have understood, so I advise you to do everything (or have it done ...) in cellulose wadding.

You can find more info on my site, below.

[bham]

Ah good Lumberjack you would not put a vapor barrier; do you use the vapor resistance factor "mu" for each material?
Is the mu of the plaster / brick layer higher than the mu of the adobe?

By cons in case of interior insulation finally, in the space between adobe and brick, it seems to me that the mu of cellulose wadding must be lower than that of adobe not?
If this is the case, the little vapor passing through the brick risks being trapped in the cellulose, right?

For those who discover "mu" http://foyerdemassequebec.com/Les_propr ... eriaux.pdf

Insulation from the outside: if the walls are really very thick, you have to be very careful, sometimes it's almost useless!

Why do you say that lumberjack?
Because the heating will have to heat the mass of the walls?
If that's it, once it's hot, the mass of the walls radiates by redistributing the heat isn't it?

[Woodcutter]

Ah good Lumberjack you would not put a vapor barrier; do you use the vapor resistance factor "mu" for each material?
Is the mu of the plaster / brick layer higher than the mu of the adobe?

Specify your thought, there it is a little vague ...
In which case ?
If it is for exterior insulation, it is useless: there is no massive addition of water vapor through a thick wall, especially in adobe!

In addition, rather than mu, it is better to speak in Sd, we really know what we are comparing!
Example: I use a very breathable cellulosic vapor brake, but if I give you its mu (8700 ...) you will deduce what?

While the Sd is 2 m. (Sd = mu * thickness in meters, the unit is the equivalent air gap meter)

By cons in case of interior insulation finally, in the space between adobe and brick, it seems to me that the mu of cellulose wadding must be lower than that of adobe not?
If this is the case, the little vapor passing through the brick risks being trapped in the cellulose, right?

If we imagine a layer of 1 cm of plaster and 4 cm of brick, the corresponding Sd must rotate around 0.5 m.
Cellulose wadding has a mu of 1 to 2 so the wadding thickness of 10 cm maximum will have an Sd of 0.1 to 0.2.
I do not know the mu of the adobe, but since it is raw earth, it must be lower than that of terracotta.
In theory, therefore, we end up with an outer "layer" which slows down water vapor more than the intermediate layer, but we must not forget that, given the quantity of material available in a rammed earth wall and its capacity to absorption-desorption of water vapor, we can be sure that there will never be any problems!
Especially since the rammed earth is relatively insulating in itself, the temperature curve through the wall means that we must not reach the dew point on the internal face, I think.

For those who discover "mu" http://foyerdemassequebec.com/Les_propr ... eriaux.pdf

Insulation from the outside: if the walls are really very thick, you have to be very careful, sometimes it's almost useless!

Why do you say that lumberjack?
Because the heating will have to heat the mass of the walls?
If that's it, once it's hot, the mass of the walls radiates by redistributing the heat isn't it?

Yes, before benefiting from the effect of limiting thermal losses on the exterior, the temperature of the entire mass of the wall must be increased to the temperature of the room. It can represent several hundred kWh, to repeat each year if the house is allowed to cool.

In addition, in an old house, one cannot cut the heat losses down, in the base of the walls which will be hot too ...

So it deserves serious consideration before being considered, because in addition it is quite expensive.

[Sp-Insulation]

Hello everybody

Each insulator represents its own characteristics, adapted to different types of climate.
A house in a mountainous region will not need the same insulation as a house by the sea.
There are 3 groups of thermal insulation:
synthetic insulators (based on petroleum products): polystyrene, polyurethane;
mineral fiber insulation: rock wool, glass wool, perlite, ...
insulators made from vegetable or animal fibers: cork, linen wool, cellulose wadding, wood felt, hemp, coconut wool,
sheep wool, feather ...
They must respect a thickness defined by the Thermal Regulations 2012 (RT 2012) which allows each insulator to be at the maximum of its capacities to insulate.
The insulation can be placed in a panel / roll or blown in the attic with a crust finish for the cellulose wadding.
Do not hesitate to contact us for more information.

[Gaston]

Already posted here.

[Woodcutter]

Does he advertise everywhere?

[Alain SEILLÉ]

Hello, I plan in early 2015 to start the renovation of a house that has not been inhabited for 40 years, clay floor (soon slab of lime and sand) and excellent roofing.
I want your opinions on my 4 interior walls, I plan (if possible, you will tell me) to install paneling in stages and thus fill the void between existing walls (no square in places) and paneling, the void would be filled with earth / lime / straw / sand (mixed with the concrete mixer), this would have triple advantage, the paneling would serve as formwork, additional insulation, and finish because will be painted then,
alain from 44