Leak onto lath/plaster

[Carol]

My cold water tank sprung a leak a few weeks ago pouring water down through the ceiling and beams. Luckily it was at a weekend so was spotted quickly! Now it is dried out I am thinking about the stain from the oak beams and re-decorating. So far the plaster is still well attached and I am hoping to avoid a hefty insurance claim. What should be used on the brown stains which won't upset the lime plaster ? Found some spray stuff in the DIY place but it didn't look very suitable.

Any ideas? Having just brought back ginger puss from V-E-T following expensive dentistry am keen to do it economically. £280 for extractions, anaesthetics and medication, but at least he no longer smells revolting!

 

[DJH]

Firstly I would advise Carol that you let everything dry out thouroughly and gently. The plasterand lathes will take along tome to dry out and then I suspect a coat of whitewash will do the job nicely.
You don't say if the ceiling is 'drooping' at all but that can be repaired by firstly propping it up using a cushion of something like bubblewrap on a flat board to gently jack the ceiling back up. An acrow prop is ideal but anything long enough to push the board up keep it there will do. The next thing to do is to pop up into the attic with Henry the vacuum and clean the area that is drooping. After that, if it's possible, carefully thread some fine wires(copper or galvanized) under some of the lathes (one or two or even more wires for each lathe) and then wrap or tie the wire either around some pieces of wood which span the joists or a put a screw into the wood and wind it around that. Next you'll need to lightly dampen the lathes and plaster and then spread a good layer of plaster of Paris over the affected part. Leave it for a day or two and then carefully take the prop(s) away from below.

In the future you can put some strain on that section of the ceiling by giving the pieces of wood that span the joists a turn or wind it around the srews once or twice.

It's worked for me in the past....

Doug

Later edit. I've just remembered that an alternative way if you can't get a wire under the lathes, is to screw in some short screws with washers into the lathes (taking care not to screw through the plaster) and twist the wire around the screw under the washer and then around the timber across the joists.

 

[Penners]

I have no experience of this kind of problem, so I'm sure that DJH's clearly experienced answer will be helpful. My only slight concern is the recommendation to support the ceiling on a cushion of bubblewrap. I fear this may considerably reduce the drying effect of air circulation across the affected area.

 

[Flyfisher]

We sufferer a similar problem last year, resulting in a ceiling so wet that the paper peeled off. That wasn't a problem in itself - indeed it saved me a decorating job! - and the ceiling subsequently dried out with no apparent damage, albeit with some staining and a bit of mould that had to be cleaned off when everything had dried. That was in stark contrast to a previous house where a leaking pipe caused the plasterboard ceiling to disintegrate and collapse.

Because we have yet to decorate, the whole incident was far more benign than I had feared. These old houses can be pretty resilient!

 

[Penners]

FF - was the water-staining on the lime plaster easy to cover? How did you do it?

 

[Flyfisher]

The entire room is due to be decorated and I haven't yet got around to it.

My current thought is to cover it all with lining paper first before painting, but that'll be a question for the future because we haven't really decided on things.

 

[DJH]

I'm sorry Penners I didn't make it clear that the bubble wrap is only used as a cushion to press the ceiling back up while the repairs are carried out and then taken away when it's safe to do so then letting everything dry out. Thanks for pointing that out.

 

[Penners]

Sorry, DJH, I misunderstood.

 

[Carol]

Ceiling is firm and unsaggy, now all has dried out. Main problem is terrible staining on the wall below, old and smoke blackened beams make a lovely mess! Have bought a tin of stuff that is supposed to cover up stains but would like to know if it will cause no problems with the plaster. Wonder if it might be possible to use something like sugar soap to remove some of the marking or if it is better just to cover it up?

Can't face thought of lining paper, am having dark thoughts about costs of period property owning since I was widowed last year. Rest of room was just emulsioned!

 

[Feltwell]

Lath & plaster is fairly tolerant of a one-off soaking, unlike plasterboard. So long as you've let it dry out thoroughly it will be fine.

If the rest of the wall is emulsioned then using a stain block paint won't do any harm. Most stain block paints are just emulsions with extra pigment basically - Ronseal's was when I dealt with them years ago - is yours a white paint? If so that will be likely what it is. Not very breathable but if the rest of the wall is emulsioned anyway then it won't make much odds.

 

[Penners]

Most stain block paints are just emulsions with extra pigment basically

Really? I thought they had a shellac content.

 

[Feltwell]

Really? I thought they had a shellac content.

Not that I've heard of Penners, but I'm far from being an expert on paints. I dealt, admittedly a few years ago, with the Ronseal and Cuprinol brands and they were basically super-opaque white emulsion. I have heard of zinc based stain blockers though.

 

[MdB]

Mica and our old friend calcium carbonate are also used.

 

[Penners]

And perhaps titanium dioxide?