Thermal and acoustic insulation

[jaffry26]

hello, I would like to isolate my floor at the thermal and acoustic level on a surface of approximately 20m ². I have seen a lot of topics but I am not decided yet, because I want the most natural materials possible.
is hemp effective? cellulose if not?
is there a material that is even more comfortable for the summer?

Thank you in advance for your answers.

[jaffry26]

I also found a link to the different criteria to take into account http://www.maisondesbioenergies.com/la-maison/le-confort-thermique.php
also the table that is already present on the forum https://www.econologie.com/forums/tableau-comparatif-des-isolants-t2977.html
so I restart the subject ... but I do not know if these insulators can do thermal and acoustic

[Christophe]

Cork is a natural thermal and acoustic insulation interesting but quite honest ...

[aerialcastor]

Is it to insulate the floor of the attic?

For summer comfort it is the diffusivity (phase shift) that must be taken into account.
The lower the diffusivity, the more heat, but the time it takes to cross the material.
From the data I have (to check because not cross-checked)
diffusivity:
cellulose wadding (35kg / m3): 1.3 * 10 ^ -3 m² / h
hemp (30kg / m3): 3.4 * 10 ^ -3 m² / h
granulated cork: 1.5 * 10 ^ -3 m² / h


It is therefore the wadding that is best placed for summer comfort. In addition she plays a good acoustic role.

Cork is a material that resists moisture and is renewable (provided it is used without excess, resources are limited). I find it a shame to use it in the attic where all its features will not be exploited. Let's keep it for the underbody and the floor, where there are no alternatives other than polymachin.

[jaffry26]

hello and thank you for your answers.

a friend had just spoken to me about cork but in fact it's quite complicated if you have to renew it.

At the same time, I also read that many other insulators do not take two decades without being changed ...

there is of course the price that hinders me a little: I did not think so expensive, unless there are tips to order in large quantities and benefit from cheaper rates?

Can a concrete / sand mix hold on it?

[Superform]

For cork, no, do not renew it, arialcastor just says it's renewable. In my home there is an association that recycles the corks to make loose insulation. Recycled, recyclable, fireproof, does not interest animals ... everything to please!

[Obamot]

Eternal debate. I know this issue has been debated here and we are not all exactly of the same opinion. However:
1) lightweight, low density materials are the best thermal insulators (ie argon used in double or triple glazing).
2) heavy materials, high density are the best sound insulators.
(ie concrete, glass etc.)

As a counterexample, a concrete wall also insulates from the cold, but it takes a few meters of thickness to reach a reasonable coefficient of conventional thermal insulation, but not with the same comfort (impression of cold despite everything) ... Who has already slept in an atomic shelter will know what I want to talk about )

Cork is indeed a good thermal insulator, but if you want to use it as sound insulation, it will take a thickness such that the price will be quickly dissuasive.

Often relatively light thermal insulators and purportedly also offered as “sound insulators” are often only “sound correctors” and often marketed with biased data sheets “to sell”.

To do this, they publish the isolation gain in dBA rather than in weighted measure (dBB and there it changes everything - spotting whether this mention is mentioned or not, often helps to defeat the trap.)
The best is still to choose a material, the most powerful possible, but adapted to each case. Leave deferred work in time and proceed in stages ...