Replace suspended timber subfloor by solid concrete

[Hl.house]

Our ground floor has exposed, painted(ugly) floorboards(100+ years old) with big gaps, zero insulation and zero damp proofing. This makes the room cold and we get damp smell. There are two breathing bricks at the front of the house and one at rear. At some point the rear of the house was extended and breathing brick was covered. I don't see it anymore. Under the floorboards is crawl space. I will ask DP to measure the exact depth of the void Tomorrow. The rear room has solid concrete flooring. Rear room is 20cm below the first two rooms. I would like to lower the middle room floor to level with the rear room floor to make a big kitchen diner.
Does it make sense to lower/replace the joists put new floorboards and new floor covering? or, am I better of doing a solid concrete flooring? What is the approximate cost of solid concrete flooring?

 

[omega015]

Do you have internal walls that sit on the floorboards/joists that you want to lower? If I understood you correctly then removing those joist might require some structural as not to effect the rest of the house/floors and require building control, surveyors etc.... if you have load bearing walls that will be effected. Do you have any pictures of the areas/void and floor plan etc... so that we(I) can better understand?

 

[Hl.house]

Do you have internal walls that sit on the floorboards/joists that you want to lower?

No load bearing walls on the joists/floor area that I need to lower.

Do you have any pictures of the areas/void and floor plan etc... so that we(I) can better understand?

I will need to lift floorboards to do a picture. They are full of nails at the moment.

Do you know the approximate cost of solid concrete flooring? I am trying to decide if I should stick with suspended timber or change to solid concrete.

 

[TheKeymeister]

Cost would depend on how much backfill (type 1 or 2 stone followed by sand blinding most likely) is required to bring it up to level, you wouldn't concrete the whole lot, plus cost of concrete and labour in your local area. Then factor in how easy it would be to get the concrete from the mixer into the room, you're likely to get at least some mess whilst countless wheelbarrows go backwards and forwards

Also bear in mind any electric cables or pipework within the crawl space will need to be diverted or protected beforehand.

With all this in mind I'd imagine you'd be better off going with a lower suspended floor.0

 

[Hl.house]

Cost would depend on how much backfill (type 1 or 2 stone followed by sand blinding most likely) is required to bring it up to level, you wouldn't concrete the whole lot, plus cost of concrete and labour in your local area. Then factor in how easy it would be to get the concrete from the mixer into the room, you're likely to get at least some mess whilst countless wheelbarrows go backwards and forwards

Also bear in mind any electric cables or pipework within the crawl space will need to be diverted or protected beforehand.

With all this in mind I'd imagine you'd be better off going with a lower suspended floor.0

Thank you for replying.
No electric cables but two central heating pipes which is to be be changed to UFH. Getting concrete in should be fairly easy as there is no barrier apart from the front door.

Current void depth 60cm. After lowering floor by 20cm void depth will be 40cm. Area to fill is approx 15sqm (0.4 x 15 = 6 cubic metre) Is the cost calculated per cubic metre? What will be the rough cost per cubic metre?

 

[foxhole]

You will need 100mm of insulation under the screed , had mine pumped in took under an hour and no mess.