Damp issues arising from pipe works?

shanclover

We just moved into a 1930s house and noticed damp around the walls on the ground floor. We had some plumbers around and they said they are 100% sure there is no water leaks.  We lifted up the carpets and saw there seemed to be pipeworks running through the concrete floor. The newer cemented part does have a higher damp reading. Does this mean the DPM has been damaged/ failed? What we could do get this issue solved? Thank you 

FreeBear

How are you measuring the damp ?

If it is with one of those meters with prongs on the end, you need to be aware that they are only good for untreated timber. Sticking the prongs in to anything else will give inaccurate/misleading readings.

Assuming there is a DPC in the concrete section, it will not "fail" - It will be protected from the environment and any damage by the concrete above and below. The only way it could be damaged is by drilling holes right through or physically breaking up the concrete. What is more likely is that the area is colder than the rest of the floor, and you are getting condensation forming.

princeofpounds

Damp meters are calibrated for wood. They don't really work properly on other materials, and you certainly can't compare readings across different materials as they will naturally have different conductivity.

Those buried pipes are almost certainly for your central heating system. It is very, very unusual for them to fail when encased in concrete, although not impossible. They are almost certainly not causing the damp on your walls.

Do you have any pictures of the actual damp (inside AND outside on the affected areas, large view for perspective please - cover the gutters and the ground if you can).

shanclover

FreeBear said:

How are you measuring the damp ?

If it is with one of those meters with prongs on the end, you need to be aware that they are only good for untreated timber. Sticking the prongs in to anything else will give inaccurate/misleading readings.

Assuming there is a DPC in the concrete section, it will not "fail" - It will be protected from the environment and any damage by the concrete above and below. The only way it could be damaged is by drilling holes right through or physically breaking up the concrete. What is more likely is that the area is colder than the rest of the floor, and you are getting condensation forming.

Yes I’m using metres with prongs. I understand they can be inaccurate but the readings are around 30-40% at some part of the wall and I can see damp patches too. The house was empty for sometime and it could be as you said just condensation ( I do hope so!). I just want to make sure I’m not missing anything else. 

shanclover

princeofpounds said:

Damp meters are calibrated for wood. They don't really work properly on other materials, and you certainly can't compare readings across different materials as they will naturally have different conductivity.

Those buried pipes are almost certainly for your central heating system. It is very, very unusual for them to fail when encased in concrete, although not impossible. They are almost certainly not causing the damp on your walls.

Do you have any pictures of the actual damp (inside AND outside on the affected areas, large view for perspective please - cover the gutters and the ground if you can).

Yes one front wall needs repointing and it causes damp patches around the window. But the other two walls internally show damp patches too which confuses me.  Here are the photos for the internal walls 

FreeBear

princeofpounds said: Those buried pipes are almost certainly for your central heating system. It is very, very unusual for them to fail when encased in concrete, although not impossible.

The cement in concrete will corrode any copper it is in direct contact with. It will take a long time (25+ years) with good quality pipework. But there was a spell during the 1980/90s when cheap low quality copper tubing flooded the market which started to fail after 20 years (had to fix a few problems in a friend's house).

That aside, this house certainly has some damp issues. No need for a meter, they are clearly visible. Unfortunately, without knowing more about the property and the history, identifying the root cause is not going to be easy. It may be, the house originally had a suspended timber floor which was replaced with concrete. If the DPM wasn't fitted correctly or the detailing around the edges was substandard, this would cause the problems illustrated. If this is the case, fixing is not going to be cheap.

Doozergirl

What is on the other side of those walls? 

A porch?  

shanclover

Doozergirl said:

What is on the other side of those walls? 

A porch?  

Hallway. There is also a radiator. 

Doozergirl

Hmm.  Are there any roof edges in that vicinity?

Can we have photos of the other side, please? 

Was the house done up to sell?