Hello everyone,
I am new to this forum and a proud homeowner.
However, I have a question and hope someone can give me some advice.
The house was built in 1890, with brick masonry and timber framing on the upper floor.
I am currently renovating it and have almost stripped it down to the shell.
The original plan was to remove the screed down to the slab, install insulation, and put in underfloor heating.
But what I realized is that there is no concrete slab; part of the house stands on a vaulted cellar filled with ash, and the larger part rests on clay soil.
The ground is somewhat uneven—I have removed about 40 cm (16 inches) on one side and around 20 cm (8 inches) on the other.
So, theoretically, there is plenty of space to insulate, but how to do this without a concrete slab?
I was thinking of using a filler material to level the surface, maybe an insulation board like XPS, then a studded membrane for the underfloor heating pipes, and then pouring an anhydrite screed on top. But will that hold?
The heating engineer is unsure whether the insulation boards can withstand this. He said the screed would weigh about 75 kg/m² (15.4 lbs/ft²).
How should the fill material below the insulation boards be compacted? I was thinking of using a vibrating plate compactor, but I’m concerned it might cause cracks in the load-bearing walls. Does anyone have any ideas?
Good luck
Melden
I am new to this forum and a proud homeowner.
However, I have a question and hope someone can give me some advice.
The house was built in 1890, with brick masonry and timber framing on the upper floor.
I am currently renovating it and have almost stripped it down to the shell.
The original plan was to remove the screed down to the slab, install insulation, and put in underfloor heating.
But what I realized is that there is no concrete slab; part of the house stands on a vaulted cellar filled with ash, and the larger part rests on clay soil.
The ground is somewhat uneven—I have removed about 40 cm (16 inches) on one side and around 20 cm (8 inches) on the other.
So, theoretically, there is plenty of space to insulate, but how to do this without a concrete slab?
I was thinking of using a filler material to level the surface, maybe an insulation board like XPS, then a studded membrane for the underfloor heating pipes, and then pouring an anhydrite screed on top. But will that hold?
The heating engineer is unsure whether the insulation boards can withstand this. He said the screed would weigh about 75 kg/m² (15.4 lbs/ft²).
How should the fill material below the insulation boards be compacted? I was thinking of using a vibrating plate compactor, but I’m concerned it might cause cracks in the load-bearing walls. Does anyone have any ideas?
Good luck
Melden
Elina schrieb:
I also studied geology – a biologist actually doesn’t know much about clay. A geologist does.Nowadays, you often hear about clay from building biologists – building geologists have so far escaped my attention.
Elina schrieb:
Regarding load-bearing capacity, so not necessarily the floor infill but rather what the house is standing on, the question is indeed justified.Exactly. Rammed earth and rammed concrete can also be combined, typically creating cross-sections that resemble Damascus blades. The compaction process is the refinement that improves compressive strength, making it suitable for basement floors as well as foundations. This technique, now almost forgotten but slowly making a comeback, was traditional building knowledge before the era of reinforced concrete—meaning it was the standard, or "state of the art," up to around 1885. It was generally common practice in buildings from the late 19th century period.
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