Where is the DPC line

[denvysb]

Ok so that was no luck. I tried chipping out little bits of the cement from the red bottom line and two courses above and didn't hit any black slate. The more I chipped, the more mortar kept coming out. How far into the mortar should I chip away at?

 

[JohnD]

I'd have preferred to use a water jet, it will wash out mud and perished mortar.

If you don't see the slate, it isn't there.

 

[denvysb]

The internal floor is suspended with big gap underneath. If I was to take the floorboard off would I be able to see the dpc from the internal side of the wall? Where joists go into the wall?

 

[JohnD]

Probably

Though there may be a dwarf wall in the way

 

[noseall]

The internal floor is suspended with big gap underneath. If I was to take the floorboard off would I be able to see the dpc from the internal side of the wall? Where joists go into the wall?

The internal DPC will be beneath the joists.