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Damp on ceiling

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Doug71

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My mother lives in a little old house which has a few damp issues one of which has me baffled.

There are a couple of damp marks which are slowly getting bigger on one of the ground floor ceilings where it meets the wall. This is an internal wall.

damp 1.jpg


damp 2.jpg


I have lifted the floorboards in the bedroom above and there is no sign of damp or anything wet apart from a kind of tide mark on the top side of the plasterboard that forms the ceiling below. There is no plumbing or pipes anywhere near it.

I am told that the wall had damp problems so was dry lined with timber battens and foil backed plasterboard.

My theory is the damp on the ceiling is caused by moisture coming out of the old wall which has nowhere to go because it is trapped behind the dry lining, that cavity will be really damp and it's soaking into the ceiling?

Does this sound right? Any other theories? How can it be solved, will some vents help or should we get rid of the dry lining altogether and use some breathable type plaster? Could I put some holes in the ceiling above where it's dry lined to vent it although this would just be letting the damp air circulate around the first floor joist?

I think the external walls have had the same treatment but also contain kingspan.

The house is really damp in places and also has issues with dry rot :(

Any advice appreciated, Doug
 

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Woody2Shoes

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Hi -

What was the source of the damp that caused the 'damp issues'?

Was the celiing re-boarded when the downstairs wall wall re-boarded? Is the ceiling in contact with the (masonry of the) wall?

I would guess that it's unlikely that the moisture has come from condensation caused by the drying out of a previously wet wall - the scenario you describe - but not impossible.

I'd be looking at central heating pipework/rads, water pipes and the roof/gutters above. Water coming in somewhere upstairs can quite easily track sideways - potentially quite a distance e.g. running along a wall plate/wall junction.

Cheers, W2S

PS if the wall we're looking at is aninternal wall then it's unlikely to have a cavity in it - and given the age of the house even less likely to have anything in it!
 

Woody2Shoes

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Woody2Shoes":2we50r0p said:
Hi -

What was the source of the damp that caused the 'damp issues'?

Was the celiing re-boarded when the downstairs wall wall re-boarded? Is the ceiling in contact with the (masonry of the) wall?

I would guess that it's unlikely that the moisture has come from condensation caused by the drying out of a previously wet wall - the scenario you describe - but not impossible.

I'd be looking at central heating pipework/rads, water pipes and the roof/gutters above. Water coming in somewhere upstairs can quite easily track sideways - potentially quite a distance e.g. running along a wall plate/wall junction.

Cheers, W2S

PS if the wall we're looking at is aninternal wall then it's unlikely to have a cavity in it - and given the age of the house even less likely to have anything in it!
PPS what is the construction of the external walls and roof?
 

sunnybob

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Its very possible for it to be a plumbing leak. There might be a cable or a sloping piece of wood that will carry the pipe drip many feet away from the actual leak.

Get back under the floorboards and follow that tide mark.
 

Phil Pascoe

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If the wall is cob or random stone check there isn't a downpipe outside fixed to wooden pegs - these rot and allow water to track in through the wall. I had two instances of damp in my house, one was caused by this - it actually showed on a joist about three feet down from it - and the other was where the end of a batten was exposed to the elements after the roof had been renewed and the render poorly finished. This showed about eight or nine feet away.
 

Doug71

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A bit more info.

The wall that was dry lined is just an internal 4" brick wall which showed signs of rising damp, I am told the plaster kept coming off which is why it was dry lined.

External walls are 9" solid brick walls, the pointing isn't great in places.

House was modernised maybe 40 years ago, I think new concrete floor, walls re plastered, new ceilings. Think maybe 10 years ago the place got dry lined to cover up the damp walls/failing plaster, the dry lining will just butt underneath the existing ceilings.

There is no wet central heating system in the house only electric heaters. The only water upstairs is a water tank which is quite a way away and fed by pipes that run up a different wall, continue up through the floor then to the tank/ cylinder, only about a 9" vertical run of pipes straight through the floor, no pipe runs under the floorboards, no bathrooms upstairs.

When I mentioned a cavity I meant the cavity between the back of the dry lining plasterboard and the face of the damp internal brick wall.

I have left the floorboards up and am keeping an eye on things.
 

Phil Pascoe

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My friend is a very good joiner and experienced builder - he's lived in his house for forty years with a damp patch on a wall without finding the cause. :D

edit - I should of course have said without being able to find the cause. :D
 

CHJ

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Does the internal wall adjoin the outer solid wall or a chimney breast in another room?
Which way do the joists above run, at 90 deg. or in line with the wall, do they terminate in the solid outer wall?
 

Doug71

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CHJ":25t0kuzz said:
Does the internal wall adjoin the outer solid wall or a chimney breast in another room?
Which way do the joists above run, at 90 deg. or in line with the wall, do they terminate in the solid outer wall?
Yes the internal wall adjoins the solid external wall, you can just see it in the second photo and there is some damp in that corner.

The floor joist are at 90 deg to the internal wall, their ends are built in to it, they run parallel to the external wall.
 

Woody2Shoes

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Doug71":1egz1ulr said:
CHJ":1egz1ulr said:
Does the internal wall adjoin the outer solid wall or a chimney breast in another room?
Which way do the joists above run, at 90 deg. or in line with the wall, do they terminate in the solid outer wall?
Yes the internal wall adjoins the solid external wall, you can just see it in the second photo and there is some damp in that corner.

The floor joist are at 90 deg to the internal wall, their ends are built in to it, they run parallel to the external wall.
Aaaah... the left hand wall is a solid external wall and has the joist ends in it? This would be my prime suspect... What is the external finish on the external wall - render?
 

Woody2Shoes

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Woody2Shoes":4y7hzp5d said:
Doug71":4y7hzp5d said:
CHJ":4y7hzp5d said:
Does the internal wall adjoin the outer solid wall or a chimney breast in another room?
Which way do the joists above run, at 90 deg. or in line with the wall, do they terminate in the solid outer wall?
Yes the internal wall adjoins the solid external wall, you can just see it in the second photo and there is some damp in that corner.

The floor joist are at 90 deg to the internal wall, their ends are built in to it, they run parallel to the external wall.
Aaaah... the left hand wall is a solid external wall and has the joist ends in it? This would be my prime suspect... What is the external finish on the external wall - render?
Sorry I've just re-read your second post - external finish is brick! What direction does that wall face, what protection does it have from the prevailing wind. What is the state of the guttering/downpipes in that area?
 

MikeG.

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Doug71":33u4htrm said:
........The wall that was dry lined is just an internal 4" brick wall which showed signs of rising damp........
Rising damp won't have found its way up there. That's coming down from above, or in from the side.
 

CHJ

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Doug71":3ft1dtur said:
Yes the internal wall adjoins the solid external wall, you can just see it in the second photo and there is some damp in that corner.
OK, is it a case that the internal wall is cold and chilling the ceiling edge that is in contact with it and is attracting condensate from the room humidity because of insufficient ventilation?

Doug71":3ft1dtur said:
The floor joist are at 90 deg to the internal wall, their ends are built in to it, they run parallel to the external wall.
OK that eliminates damp coming through the external solid wall into the joist ends and tracking along.
 

Woody2Shoes

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In my experience, once an externally exposed leaf of masonry becomes saturated with windblown rain, it becomes much more permeable to water (and loses most of any thermal insulation capability as well). Further wind will push an extraordinary amount of rain straight through it, until it gets a chance to dry out enough not to be saturated any longer.
 

Doug B

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Could it not just be a cold spot that attracts condensation? I’ve certainly seen that before especially on old properties that have double glazing fitted & all drafts sealed up.

I’d clean up the patch & try putting a dehumidifier in the room for a few weeks & see what difference it makes, worth a try before going down an expensive remedial route.
 

Woody2Shoes

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Doug B":2mtmiy4u said:
Could it not just be a cold spot that attracts condensation? I’ve certainly seen that before especially on old properties that have double glazing fitted & all drafts sealed up.

I’d clean up the patch & try putting a dehumidifier in the room for a few weeks & see what difference it makes, worth a try before going down an expensive remedial route.
I think that's very unlikely. I think that water is somehow coming in from outside, through that external wall, and then tracking along a joist or two. I'd be carefully studying the outside wall (during and after rain) near/above that corner - watching how gutters/downpipes work. I don't think that remedial work need necessarily be expensive.
 

wsb1207

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Woody2Shoes":onacyqbs said:
Doug B":onacyqbs said:
Could it not just be a cold spot that attracts condensation? I’ve certainly seen that before especially on old properties that have double glazing fitted & all drafts sealed up.

I’d clean up the patch & try putting a dehumidifier in the room for a few weeks & see what difference it makes, worth a try before going down an expensive remedial route.
I think that's very unlikely. I think that water is somehow coming in from outside, through that external wall, and then tracking along a joist or two. I'd be carefully studying the outside wall (during and after rain) near/above that corner - watching how gutters/downpipes work. I don't think that remedial work need necessarily be expensive.
It does sound like the damp is coming through the brickwork, even if the pointing looks ok it could still be loose enough to let water past. We had something similar on a job a few years ago. After repointing we 'painted it ' with Stormdry protection cream and that solved the problem. I doubt that the cream on it's own would have worked though given the state of some of the pointing.
 

Doug71

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Doug B":32p1m232 said:
Could it not just be a cold spot that attracts condensation? I’ve certainly seen that before especially on old properties that have double glazing fitted & all drafts sealed up.

I’d clean up the patch & try putting a dehumidifier in the room for a few weeks & see what difference it makes, worth a try before going down an expensive remedial route.
It did have new double glazed windows a few years ago which I think didn't help, I have a dehumidifier which I will put on for a while, never thought of that #-o

Here is a photo from above the ceiling showing the tide mark on the plasterboard, it's averages about 4" deep and runs full length when you look from above although you can only see the odd damp patch in the room below. The plasterboard is softer where it is darker coloured, definitely damp. I wondered if maybe it had been dry lined using a stud wall rather then just battens and the damp was running along the head of the stud wall but there is a cavity of at least 1" below the plasterboard ceiling.

damp 3.jpg


Here is the external brickwork looking very porous, should we get the whole end of the house rendered?

brickwork.jpg


Here is another problem, this was an external wall but now internal after extension was added maybe 40yrs ago, it's very damp.

stairs.jpg


As you can see the old place has a few problems. Planning on doing a lot of work on the place but want to get it right, don't want to be doing it again in 20 yrs time. Many of the problems have just been covered up/hidden away and forgotten about.
 

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CHJ

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Is this a terraced property or detached? If detached can you improve external drainage away from the footings.

Looks like external groundwater problems and the property is sitting in it with overall 'wet feet' so to speak with no damp courses.
 
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