Water Ingress?

stuart45

When lumps start forming on the surface of walls it's normally salts being brought out. There's various types, and if some of them are hygroscopic they will attract moisture as a low R/H.

ChilliBob

Thanks for the reply, not sure what you mean by R/H? - Relative Humidity?

Are you saying perhaps it's something internal and not a leak/water ingress perhaps? - I ask because if it was a leak in a gutter I'd have expected to see something running down the pebbledashing perhaps? - I guess if it's a crack behind pebbledashing though that may only present its self inside.

The fact it appears to have got worse with no rain for ages feels like a bit of a clue to me, and perhaps your (if I'm reading your reply right) internal theory has legs. If it's somehow to do with moisture, would it not present its self as mold first?

The walls are lined with lining paper, as of probably 30 years plus, not sure on the condition of the plaster behind - I know my folks haven't had them plastered, so probably original walls from when the house was built, so I'd guess 100 years or so old.

The only difference to 'living' situation for my folks is their grandson (22) staying with them - which generates more washing and more showers than they've had typically but that's about it.

stuart45

When salts are present on the surface mould won't survive on it. It's possible that the wall has been slowly damp over the winter through very small cracks in the pebbledash. It's worked it's way through over time and brought some salts with it. The salts can attract condensation which wouldn't normally form at that temperature and relative humidity.

It's only a possible theory, it could be something else.

ChilliBob

Yeah, there's many possibilities to consider, I'm guessing that scenario still results in the same conclusion though - something outside needs to be sorted before doing anything inside.

Micro cracks under pebbledsshing sounds horrendous :/

stuart45

Hairline cracks can be difficult to spot in pebbledash. Although they only allow a small amount of moisture in, if it's a strong cement mortar it tends to get trapped in the wall. It can take a while to soak through a solid wall to appear on the inside plaster.

ChilliBob

The way I'm sort of seeing this at the moment..

• Probably no visible damp or signs in the loft
• Gutter looks fine (needs to be checked)
• Pebbledashing may be an issue

I get the impression you can't really 'repair' pebble dashing to cover cracks so to speak, so not sure what a professional would suggest - clearly knocking all of one side of the house off opens you up to a world of nasty possibilities hiding under there. Not something my folks would be wanting to contend with at this stage.

If insurance aren't interested, as I suspect, I do wonder on my Mum's idea of a surveyor - not sure what they can add or if they'd be much use.

stuart45

You can use a suitable mastic to fill any cracks you find.

ChilliBob

Fair enough, that's sure preferable to the scenario I outlined :o - bet it's fun putting mastic on pebbledash :o

I wonder if I were to use some binoculars and try to scan for cracks if that'd be useful - might give it a go next time I'm over there.