A bit of background: The house is ~1860 and has no practical DPC to speak of (engineering bricks and slate at the base of the foundations). After digging out parts of the bay window for expanding the airbricks (they were badly installed - above floor level, behind the skirting boards - when the house was first built and there were serious sub-floor damp/rot issues) I found that there's a rudimentary cavity of an inch or so within the wall (filled with sand/rubble up to about 4 courses of brick). I don't know if this extends to the rest of the wall. The water table is high in this area, so any prolonged rain turns the soil underneath the floorboards to a 1-2" pond.
I moved into the house in late November, and there was a damp patch on the living room wall next to the window, spreading from the shallow bay to the wall shared with the hallway. There's a later patch of plaster immediately below the staining that corresponds to the same width - if the newspaper found packing out the skirting below it is anything to go by, the patch dates to 1956. It's the original lime plaster above this. There was a heavy build-up of salts at the join between original and later plaster. The later patch seems dry to the touch.
Currently, the height of the stain is just shy of 1m above outside ground level.
I marked the edge of the stain at the beginning of December, and it had grown a little by the beginning of January. Then it was static. Over the last couple of weeks, it's grown by a further inch in places. Despite recent inclement weather, it doesn't seem overtly linked to it - there was plenty of rain and cold between January and April.
The damp seems only to be on the very surface of the plaster. I chipped a little away that was loose and crumbly, and it's powder-dry behind. There are wood fillets in the wall for the wooden corner beads to attach to, and this is all dry and sound. There's a build-up of salts behind the plaster, on the bricks, where the old/new parts joined, too.
To the outside, in the same spot, is the ugly plastic meter box, which also comes to about 1m above ground level, but everything seems dry and there's a small gap behind it for air flow. There's some occasional deterioration to the pointing, above where the damp patch is that I'll get around to repairing shortly, alongside chipping out some badly-applied concrete pointing.
Next to the meter box, the sandstone sill has heavily deteriorated, too. Even in the corner, where's shielded by the box. I've looked outside when it's raining, and there is little rain that splashes off the box and down the side, and nothing tumbling down from the gutters. The house has Italianate/gothic stylings, with a slightly overhanging second floor that shields much of it. Indeed, there's a pile of dry sandstone dust in the corner completely unaffected by rain and wind, it's so shielded.
In the bedroom directly above the living room, there's a large damp patch in not quite the same area that seems to be caused by faulty/blocked guttering and/or a knackered bit of roof (getting someone to look at it next week, hopefully). This seems to an old problem, with the wall being patched in more modern gypsum plaster (now falling off).
So what is more likely? Water making its way down the wall from the second storey - possibly through the wall cavity that may or may not exist - and settling downstairs? Penetrating moisture from driving rain on damaged pointing? Something to do with the meter box and/or the deteriorated sill? Or could it be the incompatibility of breathable and non-breathable finishes where it's been patched over the years?
The house is a sad and abused mess, generally, so the budget for any one urgent project is tight - so if anyone could guide me to the most probable cause/s I'd be very grateful!
I moved into the house in late November, and there was a damp patch on the living room wall next to the window, spreading from the shallow bay to the wall shared with the hallway. There's a later patch of plaster immediately below the staining that corresponds to the same width - if the newspaper found packing out the skirting below it is anything to go by, the patch dates to 1956. It's the original lime plaster above this. There was a heavy build-up of salts at the join between original and later plaster. The later patch seems dry to the touch.
Currently, the height of the stain is just shy of 1m above outside ground level.
I marked the edge of the stain at the beginning of December, and it had grown a little by the beginning of January. Then it was static. Over the last couple of weeks, it's grown by a further inch in places. Despite recent inclement weather, it doesn't seem overtly linked to it - there was plenty of rain and cold between January and April.
The damp seems only to be on the very surface of the plaster. I chipped a little away that was loose and crumbly, and it's powder-dry behind. There are wood fillets in the wall for the wooden corner beads to attach to, and this is all dry and sound. There's a build-up of salts behind the plaster, on the bricks, where the old/new parts joined, too.
To the outside, in the same spot, is the ugly plastic meter box, which also comes to about 1m above ground level, but everything seems dry and there's a small gap behind it for air flow. There's some occasional deterioration to the pointing, above where the damp patch is that I'll get around to repairing shortly, alongside chipping out some badly-applied concrete pointing.
Next to the meter box, the sandstone sill has heavily deteriorated, too. Even in the corner, where's shielded by the box. I've looked outside when it's raining, and there is little rain that splashes off the box and down the side, and nothing tumbling down from the gutters. The house has Italianate/gothic stylings, with a slightly overhanging second floor that shields much of it. Indeed, there's a pile of dry sandstone dust in the corner completely unaffected by rain and wind, it's so shielded.
In the bedroom directly above the living room, there's a large damp patch in not quite the same area that seems to be caused by faulty/blocked guttering and/or a knackered bit of roof (getting someone to look at it next week, hopefully). This seems to an old problem, with the wall being patched in more modern gypsum plaster (now falling off).
So what is more likely? Water making its way down the wall from the second storey - possibly through the wall cavity that may or may not exist - and settling downstairs? Penetrating moisture from driving rain on damaged pointing? Something to do with the meter box and/or the deteriorated sill? Or could it be the incompatibility of breathable and non-breathable finishes where it's been patched over the years?
The house is a sad and abused mess, generally, so the budget for any one urgent project is tight - so if anyone could guide me to the most probable cause/s I'd be very grateful!