Replacing Concrete Floor (DPM damage)

[deanalewis]

Hi Folks,

I wrote before about my floor with the DPM with a hole in it. How come most people say just lay DPM / Lap it up the walls and then Insulate and Concrete it?

I thought it needed to be 'toothed' into the mortar to join with the DPC on the actual bricks?

I spoke to several builders who replace floors and they said just putting a new DPM down and running it up the walls a little would be sufficient but would this not cause thermal bridging with the old sub floor still in contact with the walls further down?

Would the DPM not need to be slotted into the mortar or would the wall be injected instead?

 

[Alastairreid]

Dpm and thermal bridging have no relation.
You would install the insulation round the perimeter of the slab to prevent a thermal bridge and yes the 1200 gauge Dpm laps into the dpc course.

 

[deanalewis]

Ok I had a surveyor out instead who recommended to break the slab and install a new DPM at cost of £500 inc removal and refitting

 

[JohnD]

if it can be done for £500, that seems very reasonable to me. Presumably the new floor will be to modern standards, incorporating insulation as well as a DPM.

Perhaps for a bit extra you could add UFH.

 

[noseall]

£500?

Untitled

• noseall
• 17 Jan 2015
• 3

 

[deanalewis]

Yeah

Basically tear up the original 100 mm screed, Replace the DPM / Add a layer of sand add another DPM (Lapping up walls) then Insulation then Screed.

Just as a note the floor being replaced is in an extension that was only built in 2002 - The plumber put pipes BELOW the DPM and somehow Building Control did not see this.

Room is 2.1 x 2.1 meters so he based his calculation on 100 per meter.

Other people ive been quoted by come in roughly the same

around £200 to dig it all up
and about £170 - £200 to lay a new screed.

He used his damp meter on internal walls and such and everywhere else is bone dry except where the leak was in the bathroom but the fact there is damage to the DPM he advises fixing it.

Not bad - I am based in Northern Ireland so builders here are fairly cheap.

 

[deanalewis]

Where as damp companies where going to tank the floor with an epoxy and inject walls for £2000.00 and the poblem only actually costs £500 to fix lol.