Mysterious damp

[Felix2023]

Good afternoon all,
We own a 1901 Edwardian mid terrace 2 bed property in Yorkshire. I purchased it in 2006. On the survey (back in 2006), the Surveyor picked up a little damp on a solid brick internal wall dividing the living room and kitchen. We moved in and didn’t find it an issue (no obvious damp, wetness etc). Cutting a long story short, we now rent the house out and we’ve had no problems until a year ago…..as you can see on the attached photos, the bottom of the wall is wet across the entire internal wall both sides. The only difference made to the property just before this started was changing the windows from single glazed to double. When the tenant moved out just before the summer this year, we aired the house out hoping it would dry out. We now have new tenants in and the problem is worsening. There is a radiator on the other side of that wall and copper pipes run through that wall under the living room floor - we had the pipes checked yesterday to make sure we weren’t dealing with any leaks. The living room is timber suspended (photos taken from living room) and kitchen is solid floor. Underneath the suspended floor, the timbers are dry and the brickwork is only damp in some places but mostly dry. The plumber found no leaks. There must be a copper pipe running through the solid floor from the combi boiler to that wall.
Has anyone got any experience with this please? Any advice appreciated. Thank you in advance for your feedback.

So far, the advice we have had from people are as follows:
- could be a slow leak from a pipe in the solid floor
- could be plasterwork touching the solid floor and the solid floor is wet
- rising damp
- lack of air flow/ventilation from adding double glazing

 

[Cubist]

If the copper pipes running through/under that wall are part of the central heating circuit, assuming it's a combi boiler any leak would have induced a pressure drop that should be observable on the boilers gauge. The hot water supply is not a circuit per se and there should only be one. That aside min-hole leaks can arise due to corrosion of such pipes induced by contact with mortars or plasters but such should be very obvious.

In my opinion the problem is most likely rising damp from the ground below the wall and perhaps also the solid floor slab. The poor weather this year and last has led to a general increase in the level of ground water all over the country and many drainage systems are under challenge. That increase can I think be tied directly to the damp problems observed in that wall. There is a possibility too that if the solid floor was installed fairly recently the slab will have been poured over a DPM that is now pushing excess rising damp from beneath toward all the surrounding walls. Best check them too.