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Choice of substrate for underfloor heating
I previously had a thread about insulating concrete vaults, thanks for all the answers there. I got answers to everything, but now I have another question about supporting substrates for underfloor heating.
I am renovating a patio and turning it into an extension of 15m2. The extension is built on an uninsulated vault with a garage underneath. In the future, I will insulate the garage roof (thanks for everyone's help), but right now I need to get started with the underfloor heating.
The conditions are that I have a sloped concrete floor. So, I have 50-60mm to work with for everything. Ideally, I would like to avoid using self-leveling compound, and I definitely want some form of insulation between the existing concrete and the heat distribution plate. Moisture can travel from the vault walls (which are against the ground) to the extension's floor; this will be drained in the future, so external impact will be minimal but still present.
We want tiles as the surface finish.
Here's what I'm thinking:
On the concrete floor in the extension, I lay:
1. Underlayment paper
2. Building plastic
3. Wooden joists with glued wedges or similar to level everything, now I have about 50-60mm to work with.
4. (22mm) 22mm spaced panel 20c/c and 16mm circuit with heat distribution plate.
5. (36mm) 12mm floor gypsum board
6. (48mm) 12mm floor gypsum board
7. Primer
8. (61mm) Adhesive and tiles
What do you think about it? Is there anything against it? Will the floor gypsum hold?
I am renovating a patio and turning it into an extension of 15m2. The extension is built on an uninsulated vault with a garage underneath. In the future, I will insulate the garage roof (thanks for everyone's help), but right now I need to get started with the underfloor heating.
The conditions are that I have a sloped concrete floor. So, I have 50-60mm to work with for everything. Ideally, I would like to avoid using self-leveling compound, and I definitely want some form of insulation between the existing concrete and the heat distribution plate. Moisture can travel from the vault walls (which are against the ground) to the extension's floor; this will be drained in the future, so external impact will be minimal but still present.
We want tiles as the surface finish.
Here's what I'm thinking:
On the concrete floor in the extension, I lay:
1. Underlayment paper
2. Building plastic
3. Wooden joists with glued wedges or similar to level everything, now I have about 50-60mm to work with.
4. (22mm) 22mm spaced panel 20c/c and 16mm circuit with heat distribution plate.
5. (36mm) 12mm floor gypsum board
6. (48mm) 12mm floor gypsum board
7. Primer
8. (61mm) Adhesive and tiles
What do you think about it? Is there anything against it? Will the floor gypsum hold?
Sure, double layers of floor gypsum hold up. It's considered a standard method. I would screw the bottom layer and at least glue the top one. The insulation of the floor against the garage ceiling seems like your biggest problem. I interpret it as you being able to fit 50 mm of insulation there. And that is to be regarded as quite little against an unheated space.
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