dpc higher than internal floor

[Mikest]

Hi all i'm in need of some advice. I have recently had a extension built and am a little worried about the dpc.
15 years ago we had a living room extension, we have now had the kitchen and the side of the house extended, basically wrapping the ground floor of the house.


The builder 15 years ago laid down the dpc for the living room extension 1 brick higher the origional houses flooring. Theres no step in the old living room flooring and the new concrete flooring as the builder had laid the concrete at a small fall to match up with old flooring.

Without realising that the old extention dpc was laid a brick higher the builders had matched up the dpc with the new build. its olny when they came to putting down the flooring they noticed the problem, they laid the internal flooring to match the origional houses flooring. Now that the new build flooring is laid corectly matching the existing houses floor level, this resuts in the dpc level being higher than the internal floor level by one brick.

Could this be a problem for damp? and is this a major problem?
Thanks in advance

 

[noseall]

Without realising that the old extention dpc was laid a brick higher the builders had matched up the dpc with the new build. its olny when they came to putting down the flooring they noticed the problem,

Worrying, very worrying.
At no time, did the builders not think to check the floor level inside the building the whole time that they were building up to dpc????!!!

Jeepers!

Provided that they have fitted the polythene correctly, i.e. lapped into the dpc then you should be ok. However, this will be punctured like a sieve when you fit the skirting boards.

How are they going to finish the plastering? Leave a big gap at the bottom?

 

[leew2]

I recently built an extension with the DPC about 80mm higher than floor level, this was nessacery to get the 150mm min hight of the DPC above external ground level as I wanted level access from the existing floor level. The DPM under the floor was brought up the walls and lapped into the DPC and then covered with the skirting (fixed with 'no more nails' glue). No damp trouble in the 6 months or so it's been there.

Has the DPM in your floor been brought up the walls and lapped into the DPC? If so should be fine, as long as you don't put nails through it while fixing the skirting.

 

[Mikest]

hi thanks for the reply, the dpm is lapped in to the dpc. and has been plastered over. The external ground to the rear of my house is high too. Maybe this was the reason the original extension was built with a higher dpc.

If the dpm was ever punctured then how should it be rectified? Is there some sought of liquid dpc that could be applied to the skirting area?

 

[Mikest]

I recently built an extension with the DPC about 80mm higher than floor level, this was nessacery to get the 150mm min hight of the DPC above external ground level as I wanted level access from the existing floor level. The DPM under the floor was brought up the walls and lapped into the DPC and then covered with the skirting (fixed with 'no more nails' glue). No damp trouble in the 6 months or so it's been there.

Has the DPM in your floor been brought up the walls and lapped into the DPC? If so should be fine, as long as you don't put nails through it while fixing the skirting.

hi, do you now have a step at the door? im left with a step amd was wondering if it can bee removed?

 

[^woody^]

If the previous extension was built with the DPC higher than the floor, and there have been no problems, then there should be no problems with the new extension

 

[dormermike]

This is how my 1930's bungalow was built ! DPC (bitumen) is one brick higher then the internal floor.

 

[noseall]

It is possible to have a split dpc level, i.e. the outside leaf higher than the inside (or vice-versa if the need arose).

However, it would be foolish to have the internal dpc set higher than the internal floor level. There is no point and it makes no sense.