Do I have a damp problem

[bananas4]

Not sure if this is the correct place to post this, please move if it isn't.

Last winter I had problems with the RH being 80%+, using a dehumidifier the levels would go down to the 50% range but would go straight back up if I turned it off. Last night i noticed a area half way up the wall by the front door that was peeling away and there were salt like deposits on the plaster behind the paint. If this is the problem how would i go about fixing it/ locating the problem area. I have uploaded some images of the area to imgur, linked below.

Thanks.

http://imgur.com/a/u7ydV

 

[JohnD]

is that a water pipe in your picture? Where does it go?

Have you got a water meter?

 

[bananas4]

Thanks for the reply. That is a water pipe, it is the inlet of water into the house and goes up the wall to the ceiling. I do have a water meter and have tested for an internal leak a month or two ago as the water bill had increased quite a bit turned out we were just using more water.

 

[vinn]

bananas4,
do you still want advice?

 

[bananas4]

@vinn yes please, I've been speaking with someone on another forum but they say that it will be hard to diagnose over the internet.

 

[vinn]

What material is the pipe - copper, lead, steel?
Have you noticed condensation beading on the pipe?
Can you photo at floor level, and the external position where the pipe enters the property?

Do you have damp in any other walls?

How did you test the water supply?

 

[bananas4]

What material is the pipe - copper, lead, steel?
Have you noticed condensation beading on the pipe?
Can you photo at floor level, and the external position where the pipe enters the property?

Do you have damp in any other walls?

How did you test the water supply?

The pipe looks like it is made out of copper. There is condensation beading on the pipe in the winter but there hasnt been any over the summer, the concrete floor under the carpet also gets condensation when it gets colder. The pipe enters from underground. There doesnt appear to be any damp on other walls, not sure if its relevant but in 2 cupboards in the kitchen that back onto an adjacent wall with the doors open the dehumidifier will take the RH down to 45-55% but will rise if the doors are closed, one also develops quite a mould problem in the winter as well.

I tested the water supply by taking a meter reading and leaving it for 2hours not using any water and checked it again, there was no change, the lowest measure is x0.0001m3

 

[vinn]

Thanks for the photos.

Condensation in winter is pretty normal on a water service pipe. Sleeving the whole pipe with insulation might help.
There are obvious signs of condensation on your walls.
There's also previous patches where remedial work been tried to presumably deal with the deteriorating plaster.
There also appear to be a few hairline cracks but I dont see any "salt like deposits"?

Is the wall solid or cavity?
Modern conc slabs are insulated at the edges and below, and have a membrane (DPM).
The external sand & cement plinth is in ground contact - the plinth should be hacked off 50mm above the ground.
The rendered dash was possibly installed to help prevent penetrating damp?
The flag stone is possibly raising the external level too high?

 

[bananas4]

Thanks for the photos.

Condensation in winter is pretty normal on a water service pipe. Sleeving the whole pipe with insulation might help.
There are obvious signs of condensation on your walls.
There's also previous patches where remedial work been tried to presumably deal with the deteriorating plaster.
There also appear to be a few hairline cracks but I dont see any "salt like deposits"?

Is the wall solid or cavity?
Modern conc slabs are insulated at the edges and below, and have a membrane (DPM).
The external sand & cement plinth is in ground contact - the plinth should be hacked off 50mm above the ground.
The rendered dash was possibly installed to help prevent penetrating damp?
The flag stone is possibly raising the external level too high?

Thanks for your help so far.

We've sleeved the majority of the pipe earlier this year so hopefully that will help. I managed to get my phone to take a close up shot of the original patch and it does have what look like salt like deposits, I've attached the photo so you can have a better look.

Pretty sure the walls are cavity, there is about 36cm between the inside and out side wall. The rest has gone over my head what do you mean?

 

[vinn]

The close up shows what seems like penetrating or perhaps rising damp.
The cavity might be blocked with debris, and damp could be rising up it.
The damp could be coming through from the outside dashed render
or the high ground level
or where the sand and cement plinth at the bottom of the wall is in ground contact.
Or damp could be penetrating through the concrete slab because it probably doesn't have a membrane.

Removing the skirting and checking the back of the boards for rot,
and hacking off say 300mm past all signs of damp.
Then using a 3:1 sand/lime mix or Thistle Dri Coat plaster to make good.