Do I have a hydroscopic salt problem, as i suspect?

[dgardn2012]

Hi,

I own a converted flat on the first floor of a 140 year old railway house. I currently rent the place out, but i recently have had major condensation issues, and ended up forking out getting extra vents etc installed. It has cured the extremely bad mould problem that was there but there are some really bad patches on the old chimney breast.

It may be worth noting that last October, the chimney in question had some major repairs. Some cracked bricks around the top had to be replaced, i paid extra for both flues to have air bricks installed also. The chimney cap was replaced and the whole thing re-flaunched. It has solved the chimney leak, but these patches haven't really improved any. And got darker when the humidity was high. Under the paper it looks as though someone has hacked off the plaster in the past and redone in these places. I'm guessing they didn't use a sand/cement based render before skimming.

Im a competent DIY'er what do i need to do if it is hydroscopic? I'm guessing hack the plaster off in the effected areas, then some sort of render before skimming?

Ideally i need it to be dry, or at least in a state that i can give the chimney breast a coat of matt emulsion, ideally within a week. My tenants are leaving in a few weeks, so i need to get someone in there asap. I'm guessing re papering would be ill advised for some time afterwards.

Any advice would be most appreciated.

Kind regards,
Darren

Untitled

• dgardn2012
• 27 Apr 2013
• 1

Untitled

• dgardn2012
• 27 Apr 2013
• 1

Untitled

• dgardn2012
• 27 Apr 2013
• 1

Untitled

• dgardn2012
• 27 Apr 2013
• 1

 

[Pigeon85]

If your not worried about losing a bit of space then you could damp proof the plaster that's there then baton and plasterboard then tape and easifill the joints.
No plastering needed means not waiting 6 weeks or longer for it to dry.

 

[dgardn2012]

If your not worried about losing a bit of space then you could damp proof the plaster that's there then baton and plasterboard then tape and easifill the joints.
No plastering needed means not waiting 6 weeks or longer for it to dry.

Would 2x1 timber battons do the job? Im guessing treated with cupranol or similar preserver? What would be the most ideal dmp for the job? I have seen a black everbuild liquid membrane. Would this do the job, or sheet dpm.

 

[JohnD]

is the chimney ventilated top and bottom to prevent internal condensation and damp?

 

[1john]

2xs1 tanalised would be fine (roofing batten) skim on board is fine to paint in up to 2 weeks and gives a much more durable finish than tape and fill.

Also is the chimney vented from the rooms, as asked above. What is the source of the condensation?

 

[dgardn2012]

The condensation was due to not enough ventilation, and the life style of the tenants. There were vents i installed years ago, that were effective until recent. It turned out the bedroom vent that was there was not enough and to low. Another was put in at eye level, and the mould treated with wash. It hasnt returned since. I did knock a brick out just above the the cupboard door in the breast. Its central and aprox a 2 inch gap to each flu, as the divide between the 2 turned out to be where the brick was. But if more is need the brick that seperate them is loose and will likely spin so its still supporting the rest. The heating wasnt great until about 3 weeks ago, had to have power flush and new rads due to a really bad sludge build up

 

[Pigeon85]

2xs1 tanalised would be fine (roofing batten) skim on board is fine to paint in up to 2 weeks and gives a much more durable finish than tape and fill.

Also is the chimney vented from the rooms, as asked above. What is the source of the condensation?

ideally I would advise to have the board skimmed, but as he wants it to be done in a week then tape and fill would be the ideal solution.

 

[dgardn2012]

I have been looking at various liquid dpm options, but the smallest size i have seen is 5 liters. This seems overkill, as the chimney breast is only 5x2ft and a full size door is cut into it at that, so loads left over. I have an idea if it will likely work? could the 2x1 tanalised battens be raised from the wall by using rubber or plastic washers when fastening. This way the wood still wouldn't come into contact with any damp. Then board with foil backed plasterboard. This way the wall could breath beneath rather than sealing the damp in. I could leave one side of the vent that's in the picture open, so and moister has a way to escape. I know this essentially isn't the done thing, but would it likely work?

Speed wise, i wouldn't have to apply 2 coats of liquid dpm, and wait for each to dry sufficiently. And they all suggest leaving a strip untreated to allow moisture to escape anyway. I would appreciate any advice on this.

Thanks

 

[Pigeon85]

Before you do go any further, I'm guessing this is an internal wall is there any problem with the other side of this and was it really damp and now drying out. Maybe just the remaining moisture drying out and could well be fine now and just a case of letting it fully dry. Dehumidifier could do the trick

 

[joe-90]

Tell the tenants to stop drying clothes on the radiators.

 

[dgardn2012]

Before you do go any further, I'm guessing this is an internal wall is there any problem with the other side of this and was it really damp and now drying out. Maybe just the remaining moisture drying out and could well be fine now and just a case of letting it fully dry. Dehumidifier could do the trick

The chimney breast is on an internal wall, the leak that was causing the damp was fixed last october. It may still be drying, but when i was devorating last there were patches of paper that had bubbled away from the wall. After stripping i noticed salt deposits on the durface of the plaster. At the time i thought nothing of it, cleaned the areas with anti suphate and redecorated accordingly. However the patches that were salt covered, are where its still damp. The majority of the leak was coming through cracks in the flaunching, and dripping down the flue and leaking through a gap between the lintels that make up the roof of the cupboard, and support the divide between the flues.

 

[dgardn2012]

Tell the tenants to stop drying clothes on the radiators.

they haven't been drying clothes on the rads since early January this year. I had a dryer vent installed and provided a tumble dryer since there was no other way of drying clothes... No washing line etc

 

[dgardn2012]

I have a damp meter and will of coarse check before i do anything. There is still a month until my current tenants move out. The weather warming up doubled with the increased ventilation should surely help. The damp patches on the breast could potentially take years to dry fully im thinking? The leak was fixed only 8 months ago, but i have owned the flat for around 9 years. Its always had problems, but when i got people out to look they either fixed something that wasnt the problem and couldnt find the real cause. So its been leaking all that time, although not as bad as when it was repaired. The flat was empty for 7 years prior to me buying it. I got it for a bargain price off my aunt who could no longer live there. She to had a few problems with it. If its still registers damp when the tenants leave what are my options? I can hack and patch up the affected areas, but because i need yo get somebody in there asap idealy i could do with being able to give it a coat of contract matt, just so its clean. dry lining i could do but at the same time i dont want to trap the damp. could the patches be hacked off to speed up drying, dry line leaving a couple of inces from the floor and just fasten the skirting with a 5mm gap to allow air flow. there is a vent on the breast also. the stack has air bricks on the outside now but before 9 months ago there was know air flow in the chimney other than a few cracked areas of masonry on the top. im just waying up my options, so i can budget acordingly. thanks

 

[Pigeon85]

Ideally it would be worth waiting before doing any repairs but obviously as a rented property it needs doing sooner rather than later.

If there is no sign of damp then you could also think about just removing the affected areas, treat it then pack it out with plasterboard just enough to put a skim coat on to bring it flush. I think either way would take the same amount if time just not loose any room.