In an old building (part of a farmhouse), the rear section is being renovated. After chipping out parts of the walls, especially in the bathroom, it became clear that there is approximately 8cm (3 inches) of screed. (Apparently, this consists of three layers, as it breaks in layers when chipped: two layers of about 4cm (1.5 inches) each, seemingly made of the same material, and a top layer of about 1cm (0.4 inches) – presumably a leveling compound.)
Since removing the floor to dig deeper and install insulation would be a lot of work, this option is being discarded. Installing insulation on the existing floor and then adding another screed layer would be possible given the room height of 3m (10 feet), but this is also avoided due to the effort involved. Since we manage around 30 hectares (74 acres) of forest and do not need to economize on wood chips or firewood, any potentially higher heating cost is not a concern. That is my current reasoning.
In the bathroom (7m² (75 sq ft)), the entire floor will be removed and redone because too much has been chipped out there. An electric underfloor heating system will also be installed beneath the tiles.
Here are my main questions: Is heating without insulation effective? What is the best floor structure for tiles? Is a simple screed (how thick?) with a decoupling membrane sufficient?
In the other rooms, there are some minor uneven spots. Should the floor be ground down or is it enough to apply a leveling compound?
Since removing the floor to dig deeper and install insulation would be a lot of work, this option is being discarded. Installing insulation on the existing floor and then adding another screed layer would be possible given the room height of 3m (10 feet), but this is also avoided due to the effort involved. Since we manage around 30 hectares (74 acres) of forest and do not need to economize on wood chips or firewood, any potentially higher heating cost is not a concern. That is my current reasoning.
In the bathroom (7m² (75 sq ft)), the entire floor will be removed and redone because too much has been chipped out there. An electric underfloor heating system will also be installed beneath the tiles.
Here are my main questions: Is heating without insulation effective? What is the best floor structure for tiles? Is a simple screed (how thick?) with a decoupling membrane sufficient?
In the other rooms, there are some minor uneven spots. Should the floor be ground down or is it enough to apply a leveling compound?
M
Myrna_Loy19 Aug 2021 11:06Of course, you must not undermine the foundations.
There are no foundations; the walls rest directly on the rammed concrete.
I took a closer look. The house, or rather the part to be renovated, is situated about one meter (3 feet) above the natural ground level. So the ground was heavily built up and the walls were constructed until the rammed concrete was poured. There have never been any moisture problems. Even the fill material beneath the concrete is bone dry.
According to my parents, their neighboring house is built the same way. That’s why there are no cold feet in the middle of winter when walking on the parquet or vinyl floor.
Now I’m a bit confused. On one hand, installing a new floor structure would involve considerable extra work; on the other, it seems to work well without it. Sealing the floor against moisture with bitumen or another method and pouring a thin screed over it would be quick to do and would only reduce the room height by 2–4cm (1–1.5 inches).
What do you think? It’s not that I haven’t read the many responses, but I am still somewhat surprised that the setup at my parents’ house causes no problems.
I took a closer look. The house, or rather the part to be renovated, is situated about one meter (3 feet) above the natural ground level. So the ground was heavily built up and the walls were constructed until the rammed concrete was poured. There have never been any moisture problems. Even the fill material beneath the concrete is bone dry.
According to my parents, their neighboring house is built the same way. That’s why there are no cold feet in the middle of winter when walking on the parquet or vinyl floor.
Now I’m a bit confused. On one hand, installing a new floor structure would involve considerable extra work; on the other, it seems to work well without it. Sealing the floor against moisture with bitumen or another method and pouring a thin screed over it would be quick to do and would only reduce the room height by 2–4cm (1–1.5 inches).
What do you think? It’s not that I haven’t read the many responses, but I am still somewhat surprised that the setup at my parents’ house causes no problems.
M
Myrna_Loy19 Aug 2021 21:13Murkoff schrieb:
Not that I haven’t read the many answers, but I am somewhat surprised that the construction of the family home doesn’t cause any problems.There are so many different traditional building methods that you can’t fully assess everything from a distance. However, the comfort expectations of previous generations were different, as are the renovation materials used today. If the house is heated, ventilated, and insulated the way it was 50 or 100 years ago, it can work. But if you start installing underfloor heating, modern windows and exterior doors, vinyl flooring, and if you shower and cook more often, this can lead to building damage, especially mold.
H
HausTmMike19 Aug 2021 22:37Murkoff schrieb:
There are no foundations; the walls rest directly on the rammed concrete.
I took another close look. The house, or rather the part to be renovated, sits about one meter (3 feet) above the regular ground level. So, it was built up quite high with backfill and masonry until the rammed concrete was placed. There have never been any moisture issues. Even the fill under the concrete is bone dry.
As my parents told me, their house next door is built the same way. Even during the coldest winter, your feet don’t get cold walking over the parquet or vinyl flooring.
Now I am a bit confused. On one hand, installing a new floor structure would involve significant extra work; on the other hand, it seems to work fine without it. Sealing the floor with bitumen or another moisture barrier and then applying a thin screed over it would be quick and only reduce the ceiling height by about 2–4cm (1–1.5 inches).
What do you think?
Not that I haven’t read the many replies, but I am still a bit surprised that the setup in my parents’ house doesn’t cause any problems. Theory and practice are two different things.
If the sand under the screed is completely dry, it provides relatively good insulation and future moisture problems are unlikely.
I would recommend 4cm (1.5 inches) of rigid insulation with aluminum foil facing and 4–5cm (1.5–2 inches) of calcium sulfate screed (anhydrite screed).
Install construction foil under the screed and edge insulation strips on the sides (floating installation). Done. It probably takes about 90 minutes for a 20m² (215ft²) room.
This also keeps the floor heating consumption low, assuming there is an additional radiator in the room alongside the floor heating.
Edit: Since this is an “old building,” I would double-check with a building expert. Maybe 4cm (1.5 inches) of cement screed would be better. For flexural strength, I would recommend light reinforcement mesh in the lower third (for tensile stress).
This is just my opinion/advice.
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