Damp or condensation problem – mid terrace with alleway

I know that damp has been discussed before on this forum but I can't seem to find the right answer. 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.

When the plastering was done,was it using conventional plaster or was it done by using sand/cement render.

Hi,

It was builder that did this for us but is on hols at moment so I wanted to investigate what I could just in case it is me being daft.

I remember coming home when it was first done and sure it was a sand and cement render (very gritty and there is bag of sand still in back garden), left to dry for a few days then skimmed with normal plaster.

Yeah that seems ok then. It does seem by your desciption that it is condensation rather than rising damp,if it was rising damp the worst affected areas would be lower down were as you say they are a metre high. must admit it does sound a little strange. Leaving the humidifier on will not cause any harm and will certainly make sure the walls are dried out. To be honest i would wait and see if it stops when everything is completly dried out.

Being where it is he probably used sand and cement with a waterproofer. This will hold back rising or penetrating damp but will do nothing against condensation. It is too hard and dense. A renovating plaster like Limelite would have given the water proofing but also it is a lightweight insulated plaster and breathable. This would have helped against the condensation.

The passage wall will most likely be 1 brick thick. This will be a very cold wall and will attract condensation. You could consider having the passage insulated, to much to write about on this particular subject right now but pm me and I can give you more information when I have the time.

You did the right thing getting a condensing dryer, that will save a bucket of water floating around the house wanting to condense some where. You need to have an expelair in the kitchen and bathroom when creating steam or at least keep a window open during cooking / bathing and keep the kitchen and bathroom doors shut.

You could consider whilst you are out opening what burglarproof windows you have, keep all the doors open in the house and let the air circulate around. More so in winter than summer. A breze from the cellar up to the attic would be useful. Another option is fitting a Envirovent unit. It cures condensation and is ideal for the undisciplined who cannot open windows. Costs a few hundred but it works.

Thanks, that has eased my mind a bit – things could still be drying out but just very slowly. The worst affect area is actually the patch in the kitchen by the door but this is about 30 cm in height and immediately above the skirting – this is where the old problem was but this time just smaller patch.

I am assuming that if this is rising damp it would happen some time after the plaster has had time to dry but after three weeks this bit is still drying (I think). Just coincidentally where the old problem was.

The other smaller patch about a metre up the wall is in the adjoining living room and is only small – about 3cm diameter x 2 of them but in exactly the same place as before yet the plaster was definitely stripped and dressed with sand/cement mix.

Opening the cellar is a good idea – we usually keep everything air tight which is good for keeping us warm but not good for circulating air around the house but this is something I am now learning. Thinking about it, I'm sure our cellar air brick was also blocked in by the previous owner so I guess I should re-instate this (cellar is under living room). Expelair unit also sounds like a good idea, thanks for that.

I wouldnt stress about it too much,see how things dry out,hopefully with the weather warming up you can have the windows doors open more.And yeah rising damp would not reapear as quick as that.

Hi is there an existing damp proof course to the exterior bricks - if there was you would normally see some drill holes in a course of brickwork quite low down. Most properties need a Damp Proof Course. I would suggest you get this looked at sooner rather than later - I know a company that will go out and have a look free of charge. Not only because of this wet patch but because of the damp carpet. What are the beams like in the cellar - do they look affected by anything?

Thanks, that has eased my mind a bit – things could still be drying out but just very slowly. The worst affect area is actually the patch in the kitchen by the door but this is about 30 cm in height and immediately above the skirting – this is where the old problem was but this time just smaller patch.

 

 

 

I am assuming that if this is rising damp it would happen some time after the plaster has had time to dry but after three weeks this bit is still drying (I think). Just coincidentally where the old problem was.

 

The other smaller patch about a metre up the wall is in the adjoining living room and is only small – about 3cm diameter x 2 of them but in exactly the same place as before yet the plaster was definitely stripped and dressed with sand/cement mix.

1)Draw a pencil line across the top of the damp patch and check it again in a couple of days. If it shrinks away from your line, then you know it is drying, albeit slowly. As its near the back door, is the frame sealant intact? Out of interest, is the kitchen a concrete floor?

2) Long shot, but may be a hygroscopic salt issue. The salts suck moisture from out of he room rather than damp ingress from the outside. Commonly appears on disused chimney breasts and can be stubborn, try an oil based undercoat around the spots prior to decorating.

Thanks HandyPandy,

You could be right there. The damp patch is shrinking very slowly and i would imagine that at this rate it would be about 6 weeks to completely dry. We are running a dehumidifier every night which is collecting about 2 litres per night so there must still be lots of moisture in the air probably due to years of putting wet clothes on radiators and not opening windows.

Regarding salts, i wipe off a little salt every day around the area of the offending patch. The patch is not wet to the touch, just dark and it does attract condensation if the heating and cooker is on with no ventilation.

Perhaps it is just still drying out but I will try some oil-based paint first before decorating.

Thanks again.