What is at the bottom of the floor?

[Berglund4]

Hi!
I've inherited an old cottage and in one of the rooms the floor has settled, so I thought I'd level it, and I've removed the old floorboards to see how it looks.
It seems like the floor is completely separate from the rest of the construction, is it common that they built like this at that time?
As expected, there's sawdust used as insulation, but in some areas there's a bottom layer with some clay gravel dust-like material, what is that? (see image)

 

[O]

Hello!
I have inherited an old cottage and in one of the rooms, the floor has sagged, so I thought I'd level it, and I've removed the old floorboards to see what it looks like.
It seems like the floor is entirely separate from the rest of the construction, is it common that they built like that back then?
Then, as expected, there's sawdust as insulation, but in some places, there's a bottom with some clay gravel flour-like material, what is that? (see picture)

can't see any picture

 

[Berglund4]

Images

 

[Unikt namn]

It is not enough to "upload image".
You also need to "insert image" in the post.

 

[Berglund4]

It's not enough to just "upload image".
You also need to "embed image" in the post.

How do I do that from a phone?
Can't find any option.

 

[Dilato]

How do I do it from my phone?
Can't find an option.

 

[Berglund4]

[image]

[image]

Doesn't work, too much time has passed.

 

[Dilato]

It doesn't work, too much time has passed.

Then click on

and upload the images

 

[Berglund4]

But that's what I've done..!

 

[Hep]

Images are up now.

 

[Berglund4]

Could it simply be ordinary clay?
I found that it was used in the past in both floors and walls.
It's under the sawdust, directly on the underlying layer of boards like a sort of crust, about 2 cm thick.
An old-time moisture barrier?

 

[Bonnabygg]

Could it simply be regular clay?
I found that it was used in the past in both floors and walls.
It's under the wood shavings, directly on the lower layer of boards like a kind of crust, about 2 cm thick.
Old-time waterproofing?

Crawl space foundation.
I think it looks like cement?

 

[Oldboy]

Could it simply be regular clay?
I found that it was used in the past in both floors and walls.
It lies under the shavings, directly on the lower layer of planks like a kind of crust, about 2 cm thick.
Old-time waterproofing?

Yes.

A layer of clay plaster served both as a windproofing against floor drafts and as rodent protection.
Clay plaster is suitable as it is the most pliable/flexible mortar that can withstand some movement from wood without cracking. It can also be reinforced to further reduce the risk of cracking. Additionally, it's incredibly convenient that the boards of the flooring, beams, as well as the sill can be as uneven, crooked, and twisted as possible. Compare this to building with paper, fabric, or boards. Everything must maintain the exact right distance and be even and straight, (which never happens in old houses).

It was used in the past because it was available (for free) as well as often sand and bran. History has shown that it is also the best sealing material available for floorings. It is a quick and easy way to windproof and rodent-proof a flooring, it is cheap, it is long-lasting, it is natural and contains no harmful or environmentally damaging substances, and it is 100% recyclable. Just add water to the old crumbs and it becomes new pliable clay to use.

Edit: Cement or lime mortar can also be used, but clay plaster is the best.