Concreting suspended floor

[beezo]

Hi guys,

A family member has got a 200 year old house, ground floor has given way badly and it at the point of collapsing completely. I cut a section out of the floor to reveal that the joist were completely sodden and rotting. This is what has obviously caused the floor to drop.

Now on looking closer, the damp course is higher then the timbers so there's obviously nothing stopping water traveling up the brickwork to the joists. The joist ends are not even wrapped to at least offer some protection.

Anyway, at some point half the living room floor has been concreted so she would like the same doing to this part.

The approx depth is 355mm to the soil below so should be no issues in insulating it correctly and pouring in the concreting providing there are no services underneath the floor that maybe cannot be removed for whatever reason, only way to find out is to remove the old floor first hey!

Now this house is a single brick with no cavity, the main problem I can see is that if the floor is concreted, the finished floor level will approx 100mm lower than the liquid damp course level. Now as the room will need dry lining again, I'm worried about the ingress of damp through the brickwork to the plastboard.

Is there a damp proof membrane that I can use to over come this or is there a proper way to sort this issue out? Thanks in advance for any help you can offer

 

[beezo]

Anyone?

 

[LanceCorpralJones]

Could you not finish the plasterboard just above the dpc and use a deep skirting board to cover the gap?
You could use a PVC skirting boad about 140mm wide to cover the gap. It won't rot should there be any damp come into contact with it.
http://www.nationalplastics.co.uk/index.php/pvc-skirting-boards.html

 

[beezo]

Could you not finish the plasterboard just above the dpc and use a deep skirting board to cover the gap?
You could use a PVC skirting boad about 140mm wide to cover the gap. It won't rot should there be any damp come into contact with it.
http://www.nationalplastics.co.uk/index.php/pvc-skirting-boards.html[/QUOTE]

Yes, I could and it would probably work but just wondering if there a 'proper' way to fix this. Don't understand why the damp course level is so high on the inside of the building

 

[theprinceofdarkness]

"Tank" the wall from slightly above the wall DPC to the floor DPC, using SRBF mixed with cement. It runs so put on 3 or 4 coats. The real problem is that it goes really far, a cup full will do 18" X 30' and you can only buy it in 5l containers.
Frank

 

[beezo]

"Tank" the wall from slightly above the wall DPC to the floor DPC, using SRBF mixed with cement. It runs so put on 3 or 4 coats. The real problem is that it goes really far, a cup full will do 18" X 30' and you can only buy it in 5l containers.
Frank

What's SRBF mate?

 

[noseall]

"Tank" the wall from slightly above the wall DPC to the floor DPC, using SRBF mixed with cement. It runs so put on 3 or 4 coats. The real problem is that it goes really far, a cup full will do 18" X 30' and you can only buy it in 5l containers.
Frank

What's SRBF mate?

Perhaps it it a dyslexic version of SBR....

 

[maltaron]

I am somewhat surprised that you say you have a DPC in a building from the early 1800's. Could be a later bodge. Your floor has rotted either because the ground level outside has been raised or any air bricks or vents are blocked. Houses of that age depended on ample air movement under the floor and generally around the building to keep dry. Modern living which seals all the drafts is a death warrant to an old building. I would suggest that a slate or plastic DPC is inserted in the brickwork 150mm above outside ground level and the DPC layer under the concrete floor turned up the wall and into the DPC.

 

[beezo]

I am somewhat surprised that you say you have a DPC in a building from the early 1800's. Could be a later bodge. Your floor has rotted either because the ground level outside has been raised or any air bricks or vents are blocked. Houses of that age depended on ample air movement under the floor and generally around the building to keep dry. Modern living which seals all the drafts is a death warrant to an old building. I would suggest that a slate or plastic DPC is inserted in the brickwork 150mm above outside ground level and the DPC layer under the concrete floor turned up the wall and into the DPC.

Hi, it's a liquid damp course that was put in around 10 years ago. The type where you drill 2 holes in each brick and fill with a chemical. The level of the ground outside has been raised using concrete and this is level with the bottom of the ventilation vents so this concrete needs ripping out. The vents will be bricked up before the concrete goes in.

As regards to damp proofing the internal wall to protect plasterboard/skirting board. I have seen a blue'ish varnish that was used to damp proof a cellar. Really stunk fume wise but apparently the dogs dangles. Anyone any idea what the 'stuff' is?