What should I do with this problem?

[DragonMovie]

Hi everyone!

I was going to spend today decorating but on closer inspection we’re a loooong way away from paint.

I fixed a leaky gutter a couple of months ago which I knew was causing issues, so today before decorating I hacked at some bubbled plaster and discovered that it’s still damp underneath.

I found lots of layers of repair including some bits where someone has skimmed over wallpaper (is this normal?)

I’ve stripped all the damp wallpaper away and taken as many layers as possible off. Under there are some cracks in the plaster which I’m guessing was caused by the damp or which at least explains the papering over the cracks.

My questions

1. Why is the wall still damp months after fixing the gutter? Is it because we haven’t had a summer so it hasn’t had a chance to dry? Or are the many layers of paper and plaster trapping the moisture in? Could it be because of the window (original)? See the gaps between the window and the wall.
2. What do I do next? My plan is
3. Run a dehumidifier to see if I can dry the wall.
4. Hire a plasterer if I do dry the wall and replace the window if necessary
5. Decorate.

Is this the right course of action? Is there something else I need to do too? Who should I hire to fix this?

Thanks!

Sorry - photos attached

More photos

I can't help, but this seems like a question for @PigletJohn :)

Honestly, I'd get a professional in. You don't know what you're doing (neither would I), and imo there are some things you just have to suck it up and spend money on. I tried my hand at artexing a small patch of ceiling recently. Disaster! Professional decorator did it quickly for £40. Money well spent!

I'm not a builder but these things would be worth investigating

1. where the leaky gutter was, did the dripping damage the external pointing, so the rain water is still able to penetrate the wall?
2. Is that wall cold, and does it get condensation. Is the wet from the outside (damp) or the inside (condensation on the cold wall)
3. Is the roof above intact, is damp coming down from the roof?
4. I am guessing that yes the damp has been stuck behind the layers of paint and wallpaper. Is the wall now drying out?

Given that it is raining outside on and off for the next few days, if you strip the paint/wallpaper and put a heater by the wall, you should see a visible difference quite quickly if there is no ongoing source for the damp.
If you don't then it probably is still coming in somewhere

Are you sure it isn’t coming from the window? We had huge problems with damp coming through old cracks in the masonary where the window does had been fitted.

@Disfordragon it could well be coming from the window.

@BlondeDogLady definitely up for getting the pros in. Don’t know what sort of pro though - I don’t want to pay someone to decorate if there’s some huge unnoticed issue which rears its ugly head again.

@steppemum good idea with the heater - I suppose I’ll know soon enough if there’s an ongoing water source!

Thanks all!

We had similar damp patches due to failed pointing.
Looks like a period property so maje sure you use / get whoever does it to use lime mortar as modern cement mortar is too hard.

I think the rule of thumb is a wall takes a month to dry out, per inch of thickness. And it being cold and wet weather won't have helped that.

The pinky plaster is modern plaster and this gets perminantly damaged by being wet (something to do with salts) and will need to be removed. It looks like a skim coat so you might be able to scrape it off or chip it off with a bolster and hammer. The white plaster underneath is lime plaster and that will dry out over a couple of months once it can breathe again. Once it has dried out you can get the wall skimmed in lime plaster and then paint.

You will need a plasterer who can plaster in lime.

If you want someone to do the whole thing then they might want to take it back to brick. Make sure they don't put plasterboard on and then plaster over that as the board will just rot if there is another leak.

If you stick with lime then even if it reoccurs then the plasterwork will be fine.

from the photos, I think this is a house from round about 1890, perhaps in East London, built in yellow stocks with lime mortar and originally, lime plaster, distempered, which has later been patched with gypsum.

the wall will take about a year to dry once the leak has been properly repaired. You can speed it a bit by stripping off all paint, paper and perished plaster (probably the brown gypsum) and setting an ordinary room or desk fan (not a fan heater) to blow on the damp patch. The lime plaster (creamy colour, gritty) will probably recover. It is a good idea to repair it in lime plaster, but not many plasterers are used to it. If it still has distemper on it, you can scrub it off with kettle hot water and a scrubbing brush, then wipe away with an old towel. It will not come off with cold or hand-hot tapwater. Distemper is usually in pastel colours, because it contains chalk plus colouring, and glue.

I'd be inclined to level it off and paint it with Dulux Trade Supermatt (not anything else, even with a "similar" name) which is a special paint used for new plaster, and wait for a year. Supermatt contains no vinyl and is porous allowing water vapour to escape. It is available in a small range of colours. White and Magnolia are the cheapest. It is not very durable, but you can overpaint it with any other (vinyl) emulsion ONCE THE WALL IS FULLY DRY and not before.

it would be interesting to see photos of the outside to gauge the success of the gutter repair.

Oh I love a piglet john answer.

the cool calm voice of professionalism.

(I may have a small crush...)

@PigletJohn I am VERY impressed with the accuracy of your analysis of my house!! Correct on all fronts - 1885, east London, yellow brick. I’d ask how you know but I know a magician never reveals his tricks!

I’ll post some pictures of the outside tomorrow.

There are so many layers of paper and then gypsum on top of that. Should I do my best to remove it all?

I don’t remember seeing any layers that match your description of distemper but I could have another look tomorrow and see what happens if I put kettle hot water on it.

Thanks all - very reassured to hear that it’s normal that it’s not dry yet. Will definitely look for someone who can plaster in lime.

I ran a dehumidifier in the room earlier and it didn’t measure it as particularly damp - it read 49 and I believe below 50 is ok. Being on the top floor though I’m sure this could be lower, although it also rained today so probably not a great day for running it anyway.

Thanks again everyone!

Stripping off paper and paint will allow the wall to dry faster.

The gypsum plaster is most likely ruined by being damp so scrape and chip it out to expose the wall so it can dry. You may expose whiskers. They are usually called horsehair but may actually be coconut husk fibres. Gingery brown. Horsehair mattresses were the same.

White powder will be efflorescence, scrape and brush it off dry. It will not hurt you, just mineral crystals. Any wood in the wall may be rotten and need to be removed. Look out for fungus tendrils or cuboid cracking indicating dry rot which is serious.

Distemper is a sort of paint that is washable so has some water resistance, so best removed.

As for recognising the house, I have seen similar before.

I'm a little (big) bit in awe of @PigletJohn.....