Damp or condensation – mid terrace housewith with alleway

[eljay2]

I know this has been discussed before but I can't find the answers to my own query. I wonder if anyone could offer any advice on damp or condensation – I realise the two are different but not sure which we have got, perhaps both.

We live in a mid-terrace with an alleyway adjoining two of the terraces. About a month ago we had a new kitchen put in and at the same time we had the plaster taken off right back to the bricks from the floor up to apron 1 metre as there has always been a damp patch in the corner near the door. When I say a damp patch, the area was physically wet when we have heating on so I assume this is from condensation but most of the time it was just an unsightly darker colour than the rest of the paint on that wall. however, over the past year it has grown slightly. No mould has ever been present.

After taking the paster off, it was re-plastered about three weeks ago and all dried out well except for a patch by the door about 30cm high which is still dark plaster. Also at this time, on cold day we had the heating on full plus doing a lot of cooking and this patch was then wet, again assuming condensation. We have been running a dehumidifier every night now for seven nights and have collected 1-2 litres of water in each overnight session from the kitchen. the patch is now still dark but not shrinking.

Under the floor we discovered that there was some damp carpet due to a leaking radiator (or at least we think this) but now thinking it could be underground damp. The outside wall doesn't look too bad and the guttering seems OK.

We are prone to shutting ourselves in during the winter without opening any windows and have always dried clothes on the radiators during winter but now we have a washer drier and have started opening windows more often.

Other points: there is a slight damp patch in our living room. The plaster here was stripped back to the wall and re-plastered. originally it was two patches about 1 metre up and has now come back through the new plaster in exactly the same place. The bricks out in the alleyway (next to these offending walls) seem fine.

I am baffled – can anyone suggest a cause or solution? Is there some sort of paint that can be painted internally or externally? Should I keep the humidifier going a bit longer? We are ready to decorate our new kitchen but don't want to do the wrong thing.

Thanks anyone.

 

[tony1851]

When the walls were replastered, did they use renovating plaster or just ordinary browning and/or finish plaster?
If a wall has been damp due to rising damp in the past, it is likely that it will be contaminated with salts drawn up from the ground. Some of these salts are 'hygroscopic', in that they draw water from the atmosphere and remain almost permanently damp. Renovating plaster is formulated to suppress this process.
It is probably dry in the alley because those places are like wind tunnels and will air off easily.

 

[tim00]

1. Pics would help, interior and exterior, and a scanned plan diagram of the kitchen.

2. From your research you have the usual suspects list - carefully go thro it. ie. the door opening is adjacent to the area of concern?

 

[Chit]

Are there any pipes near this wall - are they leaking ? If you lift up the carpets are the floorboards around these walls damp?

Sounds like it's rising damp in all honesty but you need to fix this before redecorating or you'll have the same problem having spent all that money on the decoration.

One thing that you could have done before you plastered the walls would have been to use a product like hardwall which is water proof or sand and cement with a damp proof course in it and then plastered over this to include a barrier for the damp.

If you still can, you may want to think about one of these options?

 

[tony1851]

what is 'sand and cement with a damp proof course in it'?

 

[tim00]

I guess that Chit is referring to an additive with the S&C mix. Far better, in my opinion, is a mix of lime, sand and cement.

Chit, If you are referring to Thistle Hardwall plaster in the hope of achieving some kind of barrier, then thats not the way to go about rendering as tony explained earlier.

I dont want to rehearse the theory and practice of remedial damp proofing, but, if you are inclined, there is lots of relevant info to be researched on this forum.