Convert Suspended floor to solid concrete

[Baz100]

Downstairs we have a suspended chipboard floor (floating) on top of polystyrene (above and between) concrete joists. (1987 build). Even though we have concrete joists, I do not like the feel of the floor. Still very bouncy - always been used to solid concrete downstairs.

We will extend out the back to enlarge the kitchen, I am keen to build extension in solid concrete, and convert the existing kitchen to solid concrete at the same time so we can lay large format tiles and without the echoey sound we currently have.

Is this just a case of removing concrete joists, excavating to the required depth and treat in the same way as the extension in terms of insulation, dpm, vents for rest of the suspended void, etc.

anything else I may come across/should consider?

with thanks!

 

[freddiemercurystwin]

How deep is the existing void?

 

[Baz100]

Ive only so far taken up a section in the corner that was rotten, it was about 1 foot below joist - but it did look like they had just piled up all the scrap rubble/timber/tiles under the house before boarding over it. Not sure the nominal depth. What is the actual construction of the suspended floor base - is it literally just earth? or is there levels of DPM and concrete?

 

[freddiemercurystwin]

The problem you'll have is that you have no idea of what the earth make up is and the chances are, as is typical of housing developments there is probably a couple of feet of made up unstable ground full of old builders crap and unsuitable to bear a floor onto so your plan is floored, if you'll pardon the pun!

 

[vinn]

I think that any made-up ground instability would have shown itself by now, so I think the OP is alright to clear the oversite rubble, and then prep for whatever kind of slab is required.
Depending on how your concrete joists are fixed you might need professional help to safely remove them.

OP, be aware that this is the kind of job where you must have worked out and BCO passed drawings - dont attempt to do it on the fly or you might come unstuck.