Replace Suspended Timber Floor with Concrete or Vica Versa?

[Gizzydash]

Hi there,

Any advice would be appreciated on following topic.

Live in a 1965 bungalow that has mix of flooring as follows: 3 bedrooms and 1 living room suspended timber floors, large main hallway victorian tiled and believe underneath no dpc/insulation etc just thin concrete layer at top and looks like compacted stone underneath, then dining room with badly laid concrete floor which is sunk down about 50mm in middle, kitchen has been added more recently (concrete, looks like no issues). Suspended timber floors better replaced at this stage - not in good shape (rotten joists, rot on wall plates due to no dpc, blocked air vents etc).

Have had some builders out who in the main suggest just getting rid of the timber floors and get solid floors in instead - my main concern with that is tying in the dpc of the new floors to the existing one in the walls. Not sure exactly how this is done and if it's guaranteed to work, want to avoid any bridging of the dpc and future damp issues.

Then I have the hallway which is not great, throw a spirit level across it and it's down about 10mm in the middle plus it's obviously very original to the build of the house i.e. thin concrete top straight onto crushed stone. The rooms that face off onto the hall show signs of efflorescence on the sub floor walls, indicating damp in that hallway floor which is no surprise given construction.

Dining room floor just looks really badly laid - dropped about 50mm in the middle, annoying at this stage having no furniture that's level

Wondering what approach to take to end up with something well laid, comfortable to live in (warm/no damp issues etc). Do I just go all out suspended timber and change over the badly laid concrete floors, or vica versa - get rid of the timber floors and relay everything modern standards solid floors, or keep the mix but relay the concrete ones. Have no idea at this stage so any advice would be appreciated!

 

[Deleted member 292770]

how much void is under the floorboards?
Has the concrete floor sunk or was it poured badly?
You don’t need to integrate your potential new dpm into the existing dpc.
Are there signs of damp in the walls in and around the hallway with the tiles?
Builders will always opt for the option which gives them the most profit.

 

[Gizzydash]

Void at shallowest is ~400mm, going down to ~500 at rear of house.
Sunk versus badly poured - i'm not sure to be honest. Looks like potentially there was a wall in the room at one stage which was taken down and then something was done with the flooring, which leads me to believe it was just poorly laid. I can partially see the build up and it looks like 100mm concrete on top and pretty loose crushed stone below that (doesn't look like type 1 or anything).
If you don't link the new dpm into existing dpc do you not get damp bridging across the floor?
Hallway - wallpaper coming away from walls at bottom. It's old wallpaper like but I think that's a sign of damp, and the efflorescence is only present on the sub floor walls facing off to the hallway which suggests moisture passing across. In general the humidity gets high in the house.
I'm open to any option really - we're probably going to be here for the long run.

 

[Deleted member 292770]

New build with brick/block would have the dpm folded under the dpc. It won’t be possible for you to do that.
Where are you expecting damp to come from ?
Sounds like either is an option but the concrete route would be a lot more upheaval if you’re living there and A lot dearer .
Is there not a dpc in the internal (hallway) walls?
I’d almost certainly pour a new floor in that area with a dpm and chemical dpc if there isn’t one.

 

[Gizzydash]

Thanks - think the upheaval point is probably the main one - getting all the sand binding, aggregate and concrete in sounds like a move out of the house for 3/4 weeks job!

 

[Deleted member 292770]

Thanks - think the upheaval point is probably the main one - getting all the sand binding, aggregate and concrete in sounds like a move out of the house for 3/4 weeks job!

I was thinking readymix .. still upheaval.