Inside Insulation: coating or wool?

[vegaman]

Hello everybody

I plan to insulate my walls from the inside (30 cm red brick + 2cm plaster coating.

I hesitate between three products:

1 / Creation of a frame (wood or rail) and laying of 8cm wood wool directly against the wall (no air gap). Then steam brake, to finish with a plaster lining

2 / Application of a lime / hemp plaster "Can project" with a thickness of 3 or 5cm

3 / Installation of Chanvribloc (lime block / hemp)

What are for you the advantages / disadvantages of these solutions in terms of thermal, acoustic comfort, cost, implementation?

For the moment I am leaning towards the ready-to-use plaster solution Can project "because it is quick and easy to apply, and above all to avoid the installation of a vapor barrier. The only thing that puts me off a little is the weak thermal resistance and I'm afraid I won't gain a lot.

The thank you box

[ATE.Conseil]

Hi,

Indeed, these are very nice ITI solutions in natural products.
First of all, the application conditions must be set:

- Whatever solution you choose, your air tightness is partly made with the existing plaster coating. A permeability test should be carried out with a search for leaks in order to perfect it in good conditions.
- This air tightness - in the case of effective insulators such as wood wool, hemp, sheep, feathers ... - must be completed on the inside, by an "intelligent" vapor brake which will be able to vary its permeability to water vapor according to temperature and humidity conditions. The two main products on the market being the Vario and the Intello
- In order not to do things in half, it is necessary to add a sufficiently high thermal resistance, making it possible to divide by 3 (at least) the losses of the wall in question. The CIDD mentions this in particular with a R additional> 3.7m².K / W... for BBC renovations, aim for a final R ranging from 5.0 to almost 7.5

That said, if we take the 3 solutions that you mentioned:

- Natural wool between frame
This solution is by far the most effective (preferably with a wooden frame ... history of not mixing wood and metal!) Since it takes 15cm of insulation to exceed the famous 3.7m².K / W of insulation. In this case, put 10cm + Steam brake + 5cm (technical sheath) + Placo (or fermacell)
- Lime / Hemp coating
At equivalent thermal resistance, it would require 43.5cm of plaster ... and that's not counting the amount of water that goes with it and therefore the drying time
- Chanvribloc
Again, the relative effectiveness of the product requires passing over 30cm blocks (R4.2)

Hoping to have lit your candle

Philippe DESON
Council ATE manager

[vegaman]

Hello,

I do not have the place to allow me to put more than 10 cm. If I put wood wool I will put 9cm in all wool + facing to reach 10cm.

I am not looking to have a perfectly insulated house but to improve it. Today my walls are without any insulation. If I choose chanvribloc in 10cm (R 1.4), will I really make big savings? Will the investment quickly pay off?

[PITMIX]

Hello
If you want to calculate the losses by the walls 30cm of solid bricks and 2cm of plaster represents approximately 30W / m2.k
Multiply this figure by the number of m2 of your walls and the difference between the outside temperature and the inside temperature.
Now if you add 10cm of wood wool you can take 11 instead of 30 and redo the calculation.
Of course this does not represent the total losses but just by the walls overlooking the exterior. Very often the openings alone represent the same loss or more according to their states, designs and dimensions.

[ATE.Conseil]

Hello,

If you are limited in thickness, I advise you either to orient yourself towards the ITE (External Insulation) if that is possible, or to favor in this case slightly less natural products such as rock wool or wool. TH32 glass (Lambda = 0.032W / m².h) which will allow you to reach an additional R of 2.8.

Ecology is not systematically where we believe it ...

Regarding the savings brought by the insulation, if you add an R of 1.4 you will save about 36W / m² of exterior wall (say 200m² approximately or 7.2kWh / year ...)

Going to an additional R of 3.7, this gives a reduction in losses of the order of 8.8kWh / year

Well, there the calculations are raw, we do not take into account thermal bridges, other surfaces, ventilation losses, air tightness, volumes ...

PLEASE NOTE: these figures do not give less energy consumption ... 8.8kWh of savings does not mean 1 liter of fuel oil ... it must correspond to something like 1000 liters ...
It would be necessary to make a complete study to know the real economy

Greetings

Philippe DESON
ATE Consulting

[PITMIX]

Hello
If you want to calculate the losses by the walls 30cm of solid bricks and 2cm of plaster represents approximately 30W / m2.K

It's Wh / m2.k sorry

[vegaman]

Very well thank you.

What do you think of this solution:

10 cm of expanded cork in panels, glued to the wall and coated directly with lime coating?

Better solution than Chanvribloc?

[vegaman]

What do you think of an 8cm cork plate insulation stuck directly on the wall and coated with lime?

I have my radiators and heating pipes to fix, how to do it with cork?

[PITMIX]

You put the radiators on your feet. It sells separately. You should do one topic for your home rather than opening multiple topics. It will be easier to follow.

[Trept1934]

Even if it is a plaster .... as much as an insulating plaster (in fact it will especially cut the cold wall effect, so the user will have less tendency to want to heat, hence the economy), but:

- a plaster only aesthetic, it is 2 passes
- an insulating coating + finishing coating, it's 3 passes

=> Patience and length of time are more than strength or rage. That said, you can make fewer passes if you are satisfied with a coarse appearance and not stucco.

For materials, any materials merchant offers lime (8 to 10 euros for a 35-liter bag) and chenevotte fibers (13 to 16 euros for a 200-liter bag). Even in the groin. There are large power stations whose salespeople have widely distributed their products in the past two years.

For such a small surface, the wall surface must be small so the workload is limited, but not dirt or construction time because of the very long drying time (several months for lime-hemp).