We have recently moved into a fifties built house, brick built cavity (50mm) walls and ground bearing concrete floors.
The DPC is visible on the outside and is minimum 150mm above ground level, the finish floor level inside the house is 75mm lower than the external DPC.
I have knocked some plaster and skirting off the inner leaf and raked the mortar joints but cannot find a DPC on the inner leaf at either floor level or at the same level as the external leaf.
The face of the inner leaf is not bitumened or similar. The existing floor was/is Marley tiled with thick bitumen adhesive which I,m guessing may be the 'DPM'?
There is no apparent damp on the walls inside - luck??
Anyone know/suggest what the likely construction detail was?
The main reason I ask is because I intend to add an extension and am really not sure how to treat this situation.
Obviously I would like the FFL in the extension to be contiuous with the existing.
In the new work do I:
Fit the inner DPC at same level as external and then lap the DPM up the wall a course from the floor? - not ideal as easily be damaged by plasters or second fix joinery and I'm not a fan of dot and dab.
Fit the inner DPC at FFL (ie 75mm lower than external leaf) and lap DPM in 'normal' manner? - will not coincide with blockwork courses and will mean 3 courses of brickwork with the two below DPC being class B's which are really hard to get round here at the moment at any price.
Phoned BC to ask and they gave the impression they didn't understand the question and told me I need to excavate the external ground level to be 150mm below existing FFL (not realistically possible) with no answer about how to interface new work
Any pointers or suggestions gratefully recieved!
The DPC is visible on the outside and is minimum 150mm above ground level, the finish floor level inside the house is 75mm lower than the external DPC.
I have knocked some plaster and skirting off the inner leaf and raked the mortar joints but cannot find a DPC on the inner leaf at either floor level or at the same level as the external leaf.
The face of the inner leaf is not bitumened or similar. The existing floor was/is Marley tiled with thick bitumen adhesive which I,m guessing may be the 'DPM'?
There is no apparent damp on the walls inside - luck??
Anyone know/suggest what the likely construction detail was?
The main reason I ask is because I intend to add an extension and am really not sure how to treat this situation.
Obviously I would like the FFL in the extension to be contiuous with the existing.
In the new work do I:
Fit the inner DPC at same level as external and then lap the DPM up the wall a course from the floor? - not ideal as easily be damaged by plasters or second fix joinery and I'm not a fan of dot and dab.
Fit the inner DPC at FFL (ie 75mm lower than external leaf) and lap DPM in 'normal' manner? - will not coincide with blockwork courses and will mean 3 courses of brickwork with the two below DPC being class B's which are really hard to get round here at the moment at any price.
Phoned BC to ask and they gave the impression they didn't understand the question and told me I need to excavate the external ground level to be 150mm below existing FFL (not realistically possible) with no answer about how to interface new work
Any pointers or suggestions gratefully recieved!