Bedroom Wall/Ceiling Chimney Damp

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gary-m

gary-m

Member
Hi all - bit of a sage this one, or it's turning into one.

We moved in a year ago and had this in one of the bedrooms:
20160222_211642_zpszkin6ykl.jpg


This patch is in line with a chimney stack which was used as a flue for a convection gas boiler (replaced May this year so chimney is now unused, cowel remains and open at the bottom). Initially, we assumed the damage was historic and been fixed although it didn't seem to be drying out.
I went on the roof and checked the flashing and also in the loft where directly above, the blocks were white with salt. Again, assumed old damage.
The flashing seems ok and also some of the pointing with some of the lead looked different so possibly confirmed this had been looked at (not ruling out a leak, mind).
IMG_20160621_201929_zpsnlfpyjtp.jpg


IMG_20160621_201916_zpsn7hqjvad.jpg


As you can see in the above, I've drilled (course above lead) and injected some dryzone, also painted with some weatherproof stuff just in case. This was Feb 2016.

The plaster still didn't seem to be drying out any (checking with meter) so got a dehumidifier which seemed to be working, to a point.

We got some plasterers in hoping for some pointers who skimmed the whole room for us. He did mention stripping off the plaster near this damage and using sand/cement but he said it didn't need it. I (wrongly) assumed he knew more than me about plaster but I gave him too much credit (as when I showed him my meter, it seemed like he'd never seen one before).

Anyway, the patch didn't dry out:
IMG_20160910_223413_zpswq4gg67q.jpg


So I chopped it all away to see what was going on (rather than pull apart the chimney!).
IMG_20160927_194736_zpsbebntca4.jpg

To the left of the red pull rod, the blocks are 2 thick and have wooden cladding and I did find one of them had a crack and also a small hole. Not too big a gap to have caused this, but I've filled them anyway (around a week ago).

Today, I've pulled out another block and my meter shows the bricks on the chimney are slightly damp (showing about 19% on meter), but what is puzzling me is why the blocks above aren't damp , including those in the loft (if it is coming from the chimney soaking up and ineffective DPC)?

I read on this forum about cleaning up the salt which can absorb moisture and cause issue, so I've also done that today (stiff brushed and pasted some water/vinegar/washing up liquid solution)

IMG_20161002_132107_zpswqj4prbs.jpg


This is the current state of the wall - blocks to the left seem ok for damp and the bricks in the right seem to be the highest from the meter (2nd brick along right from the bit of wood - seems to be centre of the stack).

Aside from buying more DPC cream and better waterproofer for the bricks, I'm not sure what to do!
Appreciate any help (if you're still awake)...

Gary
 
Welcome to the forum.
You speak of timber cladding, where is it exactly? Is it defective?
The whole thing might just be saturated.
I'm not convinced injecting drizone on a chimney is going to help.
If you have a small amount of heat in the room & a dehumidifier working, I would expect to see a dry wall. As it is not drying, moisture must still be getting in. Logic dictates that the weak area is the chimney/roof joint. I would suspect the flashing. Salts in the loft indicate a level of damp has been present for a while, which makes me think you are looking for a very small breach, and the moisture has built up over time.
This forum might not solve your problem, but there are knowledgable guys here that are going to come up with ideas that might help.
 
Lead flashings on chimney where roof abuts chimney , lead soakers should be under tiles
& one missing might be letting rain in
 
Hi, thanks for replies.
Here's a drawing of the layout and where the damp patch relates to and where the cladding is. I think the wood is ok as behind this, the wall is fine, is just where the chimney is
wall-2_zpszwe0upo0.jpg


While writing that up, the answer to me does seem to be the roof/flashing although wasn't sure.
Chimney is still there, just now unused (flue remains in place, for now and cowl on the top).

I think i'll get someone in to repair/replace flashing. Think that is best course of action?
 
i'm not sure that I understand 2 leaves of blockwork, wonder why it needed to be so thick? Is it done correctly?
 
The leak from thte caldding has seeped through to the inside chimney you need to let it dry out. Gypsum is hygroscopic and the dampness is already in the existing plaster when your fellas skimmed they should have hacked off and sbr and cement slurried and sand and cement or you can get newton membrane for the whole chimney. The drizone wont do anything there as it's not rising damp but residual dampness altreday in the brick. Where are you?
 
Dropsalot said:
i'm not sure that I understand 2 leaves of blockwork, wonder why it needed to be so thick? Is it done correctly?
Click to expand...
house built in 65 - further up, the blocks are laid flat, you can see this in the upper part of the gable end. not sure why and not sure I can answer if it's correct.

flynnyman said:
Is the chimney blocked up in the room? Any chance of a pic of the whole wall in the room?
Click to expand...
Sorry, didn't mention this - there's no fireplace in the bedroom, the chimney served the kitchen below (at originally, maybe) and more recently, the boiler. it's now redundant but still has a flue in place which is connected to the cowl.

sponker said:
The leak from thte caldding has seeped through to the inside chimney you need to let it dry out. Gypsum is hygroscopic and the dampness is already in the existing plaster when your fellas skimmed they should have hacked off and sbr and cement slurried and sand and cement or you can get newton membrane for the whole chimney. The drizone wont do anything there as it's not rising damp but residual dampness altreday in the brick. Where are you?
Click to expand...

I thought this was possible, but the patch doesn't quite line up with the crack I found (and patched up) and although wasn't directly under the eaves, was fairly close to it. If it is this, i should see it drying out fairly soon, right? I don't mind waiting a week or so to see if there's improvements and the weather is bound to test it. I would sand/cement over the patch but prefer to leave it until i know it's fixed before i do - don't want to find the damp affects somewhere else, probably below it. I'm in Warrington.

Cheers for responses, is appreciated.
 
The patch wouldnt line up directly mate as you are talking gravity and water will go downward and always take the path of least resistance first. To dry it out faster get a heatgun on it
 
sponker said:
The patch wouldnt line up directly mate as you are talking gravity and water will go downward and always take the path of least resistance first. To dry it out faster get a heatgun on it
Click to expand...

After watching that bloke on youtube, not sure i trust my damp tester anymore ;)
The cladding crack was to the right as you look from the outside of the house, but yes, i guess it could travel across and down? Or maybe there are 2 problems, old (or possible still ongoing) flashing issue and cladding hole?
Heat gun on the ceiling skim? that would mean I can just see if it goes damp again and not use my 'salt tester;' ;)
 
Throw the meter away it will always give a reading so is there a chimney breast in this room? You say it served downstairs but looking at it on the roof the there must be a chimney breast in that room?
 
My money is on the area above the roof. You need to look again there. Lead or other damage around the chimney. Rendering the part above is a good option too.
 
Here's the view from above, if it helps...
top-down_zpsldzrdyx3.jpg

No breast as such inside the room, but it's ajoined...
I think i need the flashing checked by someone who knows more than me (ie. any roofer)
 
I see :) Deffo flashing, looks like there is a bit missing in the second pic also a small hole on the top but could be the pic, the chimney is open? What kind of pot is on there? Was it plastered withstand and cement befor you hacked it off or was it a gypsum backing coat?
 
Bit missing in box (in pic below)? If so, I've put some flashing strip in there as i thought the same, done while plastering was going on so about 4 weeks. Hole in red circle? If so, is muck :)
Pot is a metal cowl with metal flue attached and sand/cement around it.
Was just plaster, not sand cement.
IMG_20160621_201916-2_zpstxw6bgvs.jpg
 
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We are getting closer to diagnosing it :) so you patched that bit up with flash band? Yeh that bit I thought was a hole :) the problem may be the chimney is not vented because you still have the flue connected to the cowel and you say the flue is no longer used? What you will have is the void around the flue which is not vented and if the flue is metal it will get cold and cause condensation which may be causing the problem. You also have a gypsum based backing plaster that will hold moisture and will never dry out. I would suggest pulling the flue out so the chimney can fully vent and plaster up with sand and cement. :)
 
Nice one, thanks. I'll remove it next weekend (if weather permits).
So the plaster removed, I'll sand/cement up - you reckon the ceiling will dry out (if there is no leak, of course, and it is damp from within the chimney due to flue)?

Thanks for help! Taken me a year of messing about (on and off) and this post might have solved it in a few hours!
 
Pull the flue out if you have no intention of getting a log burner coz they are expensive to put in, if you have no leaks this I'm sure will be the problem. It looks like a cold spot and you are not really venting the chimney hope you sort it :)
 
flynnyman said:
Pull the flue out if you have no intention of getting a log burner coz they are expensive to put in, if you have no leaks this I'm sure will be the problem. It looks like a cold spot and you are not really venting the chimney hope you sort it :)
Click to expand...
No chance of using this chimney in future, the fridge is now below it!
I put my log burner in my last place, stood on stack feeding in the flue - no scaffold or even roof ladder :)

Will check on insulation and also replace cowl when flue out.

I'll update when I've made any progress and thanks for all replies - you know if I'd have called a roofer they'd have replaced the whole flashing, charged me for the pleasure and left me with the damp patch :)
 
I think you still need to look at the roof! It's a quite big spot and for quite long time to be condensation or old stuff. Look closer at the highest area around the chimney above the roof. It's like collecting all the water and redirecting to the wall. Just an idea of course.
 
vfr12 said:
I think you still need to look at the roof! It's a quite big spot and for quite long time to be condensation or old stuff. Look closer at the highest area around the chimney above the roof. It's like collecting all the water and redirecting to the wall. Just an idea of course.
Click to expand...
Sounds like the simplest thing and I would agree it's the roof coz water comes down :) not up like some people think :)
 
Yes, it's open. The boiler had a cast iron flue connecting to the flexi flue in the ceiling (or thereabouts).
The hole is still open and will leave it that way.
 
gary-m said:
Here's the view from above, if it helps...
top-down_zpsldzrdyx3.jpg

No breast as such inside the room, but it's ajoined...
I think i need the flashing checked by someone who knows more than me (ie. any roofer)
Click to expand...
How do you do these drawings?
 
vfr12 said:
Does this mean you agree with me flynny?
Click to expand...
No












Hahahahaha that would be the simple solution but I we have to diagnose all the other problems aswell :) I die a job early this year and they had four firms out who all done work and it boiled down to a chimney that wasn't vented. The guy who's house it was gave me ten ways to do it and I told him to leave it to me and he couldn't believe the problem was so simple once I sorted it. Every day I wish I could get on the gravy train but I can't lie :( I have thought about getting other people to lie for me but I can't change :)
 
flynnyman said:
No












Hahahahaha that would be the simple solution but I we have to diagnose all the other problems aswell :) I die a job early this year and they had four firms out who all done work and it boiled down to a chimney that wasn't vented. The guy who's house it was gave me ten ways to do it and I told him to leave it to me and he couldn't believe the problem was so simple once I sorted it. Every day I wish I could get on the gravy train but I can't lie :( I have thought about getting other people to lie for me but I can't change :)
Click to expand...

Thank f**k for that! Thought for a second you are getting softy ! :loco:
 
vfr12 said:
I think you still need to look at the roof! It's a quite big spot and for quite long time to be condensation or old stuff. Look closer at the highest area around the chimney above the roof. It's like collecting all the water and redirecting to the wall. Just an idea of course.
Click to expand...

Here's pic of that - am not sure water is collecting here (and lead is lipped quite well), I don't think it is but will check after rain next.
IMG_20160621_201904_zpsu4ovaju3.jpg
 
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