basement floor

[mrmiles]

Hi,

We're looking at replacing a concrete floor in the basement of our victorian house in order to get a bit of extra headroom. The existing floor was laid on a layer of well compacted hardcore, without a DP membrane. The layer is reasonably flat, but probably about 5cm higher around the edges than in the middle.

Bearing in mind that the aim is to get more headroom, what is the minimum thickness of concrete that we can get away with? We plan to tile on top of that, and it will only have kitchen units on top of it.

Thanks,

Miles

 

[Symptoms]

miles - is this the original Victorian floor? Beware of digging out this area because there is the real possibility of de-stableizing the building's structure. Seek professional advice.

 

[noseall]

i don't think it is a good idea to furnish* a subterranean space at any price.

*furnish as in place or fix objects against the walls.

has the space been professionally (expensively) tanked?

 

[mrmiles]

Hi,

Thanks - in answer to the question it's not the original floor. The basement was converted by the council about 30 years ago, and is dry (it's not below ground) and has been in use since then (it used to have a bathroom in!).

We've dug an inspection hole - the concrete slab is about 20cm thick, then there's sand blinding and a layer of compacted hardcore under that. Our plan was to remove the concrete slab and lay something thinner, perhaps 10cm instead.

The space is 4.5m x 7m. Originally there used to be a supporting wall across the middle, dividing the space into two, but that is now gone and an RSJ is mounted in the ceiling - so it's a completely open space.

Miles