Yes it was built around 1900. The water pipes run down the passageway to the road and are lead. The drains run down the same way as well as the gas supply.
The level of the floors inside are about the same level as outside too.
He was an old boy who seemed to know what he was talking about and said he'd been correcting builders bad work with concrete floors for years but didn't show any RICS certificate. He said there was no lime mortar used by exposing some render on the corner of the passageway and showing me with his damp meter.
Next door the lady has damp in her passageway and inner walls too and had some airbricks installed for £1700 but they haven't worked as I suspected.
When we moved in the owner had to redo the walls because of a damp survey but no injection solution was installed.
When redecorating and pulling off the wallpaper I did notice the hallway had a newish plaster like the damp-proof we had just done. (halfway up the wall etc)
The guttering looks ok but there are cracks in the rendering below which I thought maybe the cause of the damp initially but it only affects the ground floor corner of the room which is the passage wall, and it goes right up to the corner top and then under the window along the skirting nearest the window.
There is also a gap in the concrete mm wide from the outside wall at the back of the house where the window has damp on the inside along the skirting. When it rains or when I've pressure washed the floor area around there the water has pooled and disappeared down the gaps as the concrete wasn't angled to get to the drain.
Damp showed over 200 on his damp meter inside the hallway inner wall and 4m across the room at the passageway wall. He pulled the carpet up in the room with the damp in and it was above 200 as well, same as the hallway concrete floor.
What possibilities are there?
The roof
The Concrete floor replacement
The cracks in the render
The pipe/s that run down the passageway out of the property
the pipes that run from the house to the passageway
The gap in the outside ground cement.
The groundwater table height.
The absence of lime mortar used
If the damp is present in the concrete floor then that would mean moisture is penetrating everywhere somehow.
Could a leaking water pipe really affect such a large area? If it was a water leak I would see it in the water bill I would have thought. But a cracked drain could be the problem that would continue to supply the house with water that wouldn't have been seen by the water meter.
How would I go about getting someone to inspect and diagnose the problem?
This has to be the next step as you mentioned but
How much would it cost to replace guesstimating the floors in two rooms the same size 4x4m and hallway 9mx1.8m?
He hasn't given me a quote yet and said it would take a week to do each room and replace it with the timber floor.
My neighbor said she has a professional to come and check the damp tomorrow in her place and has asked me to come along.
What are some good things to ask this person when I see them tomorrow? and will they give an answer to the problem by the time they've finished most likely?
I'm assuming her problem is common to my problem but could be wrong.