Have a lot of rooms in an old 4 storey victorian house that have plaster problems, also near enough all ceilings have problems (about 15 rooms worth) so need to do sometihng about them.
For example in the attic conversion There's a strip of wood at the level of the base of the original roof (couple of feet above the floorboards) and it's been plastered over (probably 20yrs ago) with a sandy light coloured plaster followed by what looks like a newer skim (pretty siure I see old paint between the layers). So below the wood there's brick work and above the wood there's brick work (so bricks built on this wood and the plaster covers it all).
The plaster surrounding the wood has lost it's key (I beleive that's the right term?) and can be knocked (with a small crowbar) relatively easily away from the wood and surrounding brickwork (this means the brick work is expossed a few inches above and below the wood). It seems to be worse closest to an outside corner of the room that's close to a dormer window (there's a couple of feet of flat wall then sloping ceilings for the roof).
Whoever added the window didn't add any insulation or waterproofing to the stud like work (a lot of the wood is the original roof) they'd added below the window which is part of the eaves. I've removed a section of plasterboard below the window and you can see the inside of the eaves, there's also evidence of mild water damage right in the corner most likely due to poor fitting flashing (I can see daylight through tiles etc.. and it's very draughty). When I first opened it, it was a little damp, now it's been open a week or so I've not seen any evidence of water (I'm assuming it's evaporating off quickly now).
In one area near the corner there were visible cracks in the plaster and a little paint had flaked/bubbled, the paint could be scraped quite easily and the top plaster skim could be scraped quite easily. wherever a crack was the whole base plaster could be easiliy knocked off (knocked of a few feet square until it was no longer easy to do).
I'm new to house rennovation so what little I know is from books, TV and commonsense,l so I don;t know what everything is called or what's normal (it's like having wood sandwiched between brick doesn't sound like a good idea to me!).
In the two rooms I've checked (there's three on this floor) the wood area of plaster is very easy to remove relative to above and below it for no obvious reasons, so I'm assuming it's either allowed water into the plaster or enough movement to damage adhesion (or maybe plaster doesn't stick to wood well long term?).
Does that make sense?
I'm not sure what to do. Seems the presence of wood is either causeing a problem or making it worse (the corner problem is more than just the wood), so need to do something about that.
I've tried plastering a couple of times (just as tests) and when I got the mix right it wasn't that hard to do a flat skim over the test area. So I don't see a problem plastering this area (and many others in the house) if thats the best solution.
Should I scrape of any loose plaster, loose in the sense that jabbing at it with a crowbar knocks it off without too much force and then replaster the damaged areas followed by a reskim to get a good finish. Or fill in the holes I've made and drywall over the lot?
If it's remove damaged plaster and make good is the proceedure is something like this-
Remove all loose plaster,
Brush away dust etc... from brickwork
PVA the wall (5:1 ratio?).
This is where I'm not sure.
is it
fill the hole with two coats of plaster, the first to fill the hole the second to get a flat finish.
Or do you do this in one go (It's under an inch thick).
Also any reccomended plaster type, I'll be buying from B&Q most likely?
I've tried I think thistle Multi-finish and I had no problems with it. My first test was with a white plaster from Wickes and it wasn't as good.
thanks for any tips.
David
For example in the attic conversion There's a strip of wood at the level of the base of the original roof (couple of feet above the floorboards) and it's been plastered over (probably 20yrs ago) with a sandy light coloured plaster followed by what looks like a newer skim (pretty siure I see old paint between the layers). So below the wood there's brick work and above the wood there's brick work (so bricks built on this wood and the plaster covers it all).
The plaster surrounding the wood has lost it's key (I beleive that's the right term?) and can be knocked (with a small crowbar) relatively easily away from the wood and surrounding brickwork (this means the brick work is expossed a few inches above and below the wood). It seems to be worse closest to an outside corner of the room that's close to a dormer window (there's a couple of feet of flat wall then sloping ceilings for the roof).
Whoever added the window didn't add any insulation or waterproofing to the stud like work (a lot of the wood is the original roof) they'd added below the window which is part of the eaves. I've removed a section of plasterboard below the window and you can see the inside of the eaves, there's also evidence of mild water damage right in the corner most likely due to poor fitting flashing (I can see daylight through tiles etc.. and it's very draughty). When I first opened it, it was a little damp, now it's been open a week or so I've not seen any evidence of water (I'm assuming it's evaporating off quickly now).
In one area near the corner there were visible cracks in the plaster and a little paint had flaked/bubbled, the paint could be scraped quite easily and the top plaster skim could be scraped quite easily. wherever a crack was the whole base plaster could be easiliy knocked off (knocked of a few feet square until it was no longer easy to do).
I'm new to house rennovation so what little I know is from books, TV and commonsense,l so I don;t know what everything is called or what's normal (it's like having wood sandwiched between brick doesn't sound like a good idea to me!).
In the two rooms I've checked (there's three on this floor) the wood area of plaster is very easy to remove relative to above and below it for no obvious reasons, so I'm assuming it's either allowed water into the plaster or enough movement to damage adhesion (or maybe plaster doesn't stick to wood well long term?).
Does that make sense?
I'm not sure what to do. Seems the presence of wood is either causeing a problem or making it worse (the corner problem is more than just the wood), so need to do something about that.
I've tried plastering a couple of times (just as tests) and when I got the mix right it wasn't that hard to do a flat skim over the test area. So I don't see a problem plastering this area (and many others in the house) if thats the best solution.
Should I scrape of any loose plaster, loose in the sense that jabbing at it with a crowbar knocks it off without too much force and then replaster the damaged areas followed by a reskim to get a good finish. Or fill in the holes I've made and drywall over the lot?
If it's remove damaged plaster and make good is the proceedure is something like this-
Remove all loose plaster,
Brush away dust etc... from brickwork
PVA the wall (5:1 ratio?).
This is where I'm not sure.
is it
fill the hole with two coats of plaster, the first to fill the hole the second to get a flat finish.
Or do you do this in one go (It's under an inch thick).
Also any reccomended plaster type, I'll be buying from B&Q most likely?
I've tried I think thistle Multi-finish and I had no problems with it. My first test was with a white plaster from Wickes and it wasn't as good.
thanks for any tips.
David
