ᐅ Insulation of the ground floor slab / underfloor heating if applicable
Created on: 18 Feb 2021 13:42
W
Winniefred
Hello!
We plan to insulate the ground floor floor this autumn. We have a house from 1921 with a vaulted cellar that is not insulated. Insulating the cellar ceiling is not an option, so we want to insulate the floor. We have been living here for 3.5 years and in winter it feels too cold underfoot, plus it’s also a building regulation requirement. We will start with the living room this year and then do the rest gradually. The cellar remains at a constant 14°C (57°F), but we want to address this to save even more on heating costs (the rest of the house is well insulated and our heating energy consumption is low).
We want to insulate as effectively as possible since we are putting in the effort anyway. The current structure is: laminate flooring, old linoleum, probably OSB underneath, floorboards, wooden beams in slag. All of that will be completely removed. I like the Fermacell floor system—it seems lightweight and suitable for DIY. The rough ceiling would need to be primed, then a bonded screed applied, followed by a rigid insulation board and then the dry screed panels. After that, I imagine a nice cork parquet or something similar.
Has anyone had experience with this setup? Or with bonded screeds in general? Are there other ideas for floor insulation that can be done as a DIY project?
We currently only have a gas heating system. Underfloor heating in the living room would be nice but is not essential. The existing radiator heats the living room perfectly well at the moment.
Looking forward to your input!
We plan to insulate the ground floor floor this autumn. We have a house from 1921 with a vaulted cellar that is not insulated. Insulating the cellar ceiling is not an option, so we want to insulate the floor. We have been living here for 3.5 years and in winter it feels too cold underfoot, plus it’s also a building regulation requirement. We will start with the living room this year and then do the rest gradually. The cellar remains at a constant 14°C (57°F), but we want to address this to save even more on heating costs (the rest of the house is well insulated and our heating energy consumption is low).
We want to insulate as effectively as possible since we are putting in the effort anyway. The current structure is: laminate flooring, old linoleum, probably OSB underneath, floorboards, wooden beams in slag. All of that will be completely removed. I like the Fermacell floor system—it seems lightweight and suitable for DIY. The rough ceiling would need to be primed, then a bonded screed applied, followed by a rigid insulation board and then the dry screed panels. After that, I imagine a nice cork parquet or something similar.
Has anyone had experience with this setup? Or with bonded screeds in general? Are there other ideas for floor insulation that can be done as a DIY project?
We currently only have a gas heating system. Underfloor heating in the living room would be nice but is not essential. The existing radiator heats the living room perfectly well at the moment.
Looking forward to your input!
Winniefred18 Feb 2021 15:27From the basement, it is clear that everything above the structural vault is currently 5.5cm (2 inches) thick (floorboards, OSB, linoleum, laminate). I don’t know how thick the vaults themselves are, of course. However, I don’t think we will need to remove large amounts of material. Under the center of the caps, I measure 2.09m (6 ft 10 in), and under the center of the supporting arches, 1.92m (6 ft 4 in). At the supporting columns, the arches start at a height of 1.82m (6 ft). The entire structure is made of bricks and mortared.
How much filling will be needed above the raw ceiling is uncertain, but this gives a rough idea to estimate. Dry screed panels, screed infill, etc., can then be adjusted to the desired final height. I think we will use screed infill, as we had good experiences with it in the bathroom on the upper floor. The basement obviously involves building physics requirements that we never had to consider elsewhere in the house. And this is where I have the greatest uncertainties. We have a system that has worked for 100 years. Naturally, I don’t want to build anything that will later cause condensation and mold.
Pagoni, I will take a closer look at the systems you mentioned!
How much filling will be needed above the raw ceiling is uncertain, but this gives a rough idea to estimate. Dry screed panels, screed infill, etc., can then be adjusted to the desired final height. I think we will use screed infill, as we had good experiences with it in the bathroom on the upper floor. The basement obviously involves building physics requirements that we never had to consider elsewhere in the house. And this is where I have the greatest uncertainties. We have a system that has worked for 100 years. Naturally, I don’t want to build anything that will later cause condensation and mold.
Pagoni, I will take a closer look at the systems you mentioned!
N
Nice-Nofret18 Feb 2021 15:29Thick wool carpets provide good insulation – that’s why they have been so popular for centuries.
Winniefred18 Feb 2021 15:33Nice-Nofret schrieb:
Thick wool carpets provide good insulation – which is why they’ve been so popular for centuries.Yuck, carpets, no thank you. We have kids and pets.
In our living room, the temperature is always around 20–21°C (68–70°F), and the floor temperature was recently about 15°C (59°F)...
Winniefred18 Feb 2021 15:34I am a typical representative of the half of humanity that tends to feel cold. Over the past few weeks, I have only managed to get by with two blankets and a hot water bottle that my dear husband prepares for me every evening. We definitely need to change something about this.
Winniefred22 Feb 2021 11:58I have now spoken with neighbors who have the exact same house. They even installed underfloor heating 25 years ago, but with liquid screed. It has a separate heating circuit connected to a simple gas boiler. They are very satisfied and would do it again.
I think I'll ask our heating engineer how complex it would be, specifically the "rough installation" for it.
I think I'll ask our heating engineer how complex it would be, specifically the "rough installation" for it.
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