Damp treatment on victorian brick house?

[elleread]

Hello.
Having read through some old posts, I realise what a minefield this subject is, but I hope I can get some useful advice here.
We live in a Victorian brick-built end-terrace house. When we moved in just over a year ago, the survey showed up some areas of damp in the dining room chimney breast, but the advice was 'it's just one of those things you have to live with in a house of this age' (you can't actually see any damp patches).
We have now got a large (and spreading) area of damp (visibly obvious- and very wet to the touch) around the chimney breast and exterior wall in the loft conversion which is our main bedroom.
Today we had a survey by a local company who tested all our walls with a damp meter which appeared to show very high levels in all walls. He said it was penetrating damp and recommended a chemical treatment to the entire exterior brickwork (which you can see is quite crumbly and porous in places) which apparently stops water penetrating while still allowing the wall to breathe.
Is this a good idea? Will it cure our very damp bedroom? Or is that more likely to be condensation, or a problem with the roof? There are no other damp stains in evidence anywhere else in the house.
Sorry this is a bit long-winded, I just feel very confused by all the advice I have read.
Thank you.
Eleanor

 

[Gareth Hughes]

Hello.
Having read through some old posts, I realise what a minefield this subject is, but I hope I can get some useful advice here.
We live in a Victorian brick-built end-terrace house. When we moved in just over a year ago, the survey showed up some areas of damp in the dining room chimney breast, but the advice was 'it's just one of those things you have to live with in a house of this age' (you can't actually see any damp patches).
We have now got a large (and spreading) area of damp (visibly obvious- and very wet to the touch) around the chimney breast and exterior wall in the loft conversion which is our main bedroom.
Today we had a survey by a local company who tested all our walls with a damp meter which appeared to show very high levels in all walls. He said it was penetrating damp and recommended a chemical treatment to the entire exterior brickwork (which you can see is quite crumbly and porous in places) which apparently stops water penetrating while still allowing the wall to breathe.
Is this a good idea? Will it cure our very damp bedroom? Or is that more likely to be condensation, or a problem with the roof? There are no other damp stains in evidence anywhere else in the house.
Sorry this is a bit long-winded, I just feel very confused by all the advice I have read.
Thank you.
Eleanor

Under no circumstances treat the exterior brickwork with miracle-gunk. It will not solve your problem, and in the longer term may well make it worse.

Possible sources of damp (not an exhaustive list):

Failed pointing to exterior brickwork - repoint in a mortar mix to match the existing
failure of external brickwork (mortar and bricks) - cut out and replace spalled or cracked bricks
Failed flaunching to chimney pots / pointing at top of stack - re-seat pots and repoint
Failed flashing where stack emerges from roof - replace flashing
Insufficient ventilation within redundant chimney flues - check internal vents
Failure of roof covering - check for damaged, missing or slipped slates / tiles
Failure of guttering / downpipes - go and have a look for drips and dribbles when it rains

Eliminate all of these by tried and tested traditional methods, don't go for a chamical treatment which will do no good.

And remember, it's been an unusually wet year

 

[Gareth Hughes]

Oops, hit quote instead of edit :roll:

 

[Nemesis]

And remember sticking a meter in a wall is not the most reliable methid of diagnosing damp.

If you wish to flog expensive treatments to the gullible, however, it's a very useful tool.

 

[elleread]

Thank you. This is very helpful. I did have the feeling he was more of a salesman than anything else.
The brickwork around that area is noticeably deteriorated. Would you advise that this is the first thing to try- having the worst bricks cut out and replaced? What about the pointing- is cement mortar acceptable or should a more traditional mortar be used?
It seems that whoever we get round to look at the problem (have had roofers, builders, chimney specialists...) has a different opinion and are all trying to sell us something!
Does anyone have advice on finding a reputable tradesman? We live in Nottingham.
Eleanor

 

[JMartin]

There are a plethera of companies claiming that their product will eliminate penetrating damp. All are just trying to flog their product by tapping into homeowner's fears and discomforts.

I'm not very experienced in fixing the problems of the sort you have using more traditional methods so I'll bow out and leave you to more experienced hands.

 

[Matt Green]

What is the current internal finish on the end wall?

Did you just plaster directly on the brickwork and have you used emulsion paint?

Can you describe what syptoms you are seeing too.

cheers,


Matt Green

 

[Gervase]

I can only echo what Gareth has said, and advise you to avoid any chemical treatment at all costs - they invariably cause far more damage than they purport to cure.

 

[elleread]

Hi.
We didn't do the loft conversion so I can't be totally sure of the way it has been finished.
It seems that the plaster is directly on the brickwork on the end wall and chimney breast. The wall was most likely painted in emulsion.
The damp patch started on the end wall in the corner where the chimney breast meets the angle of the roof and has now spread to the inner part of the chimney breast (the bit sticking out into the room, if you see what I mean) as well as about a foot into the end (exterior) wall. It is much more damp on this exterior wall.
We had one of the chimneys lined for an open fire about a year ago and the other (redundant) has very recently been capped as it was letting in a lot of rain. It is open and ventilated at the old fireplace however.
As I said, the brickwork on the outside of the chimney is in poor condition, although the flaunching has recently been checked as new chimney pots were fitted. The flashing has in the past been sealed with bitumen. The slates are old and a lot of water runs down between the chimney stack and dorma window.
I'm definitely against chemical treatment now but I just want to know what to tackle first!
Eleanor

 

[Matt Green]

I've never liked the diagnosis of "driving rain through the brickwork" as a cause of damp- and it should give a more uniform distribution pattern than the one you are seeing.

Flashing leaking around the chimney sounds a fair bet.

It could also be water trapped in the brickwork from a time before the works to the chimney to make it watertight slowly moving through to the interior. That would give a bubbling of the finish as the water behind pushes it off.

If it feels damp to the touch it may well be water condensing on the highest and coldest part of the room.

Solving damp problems without seeing them is painful.


Matt

 

[elleread]

Would posting a pic help? How do I do this?
Some of the paintwork is definitely bubbling, other parts are kind of sticky and damp. (The stickiness I attribute to the time in the spring when it dried out- I optimistically painted anti-stain paint on the area then emulsioned over - didn't work - obviously..!)