How much loose plaster to remove??

Hi,

I am replacing a ceiling and internal walls, but the plaster on the external wall is pretty ropey in places too. I have pulled off the obvious loose areas of plaster.

Does anybody have any pearls of wisdom regarding how much of this plaster I should be removing? I'm sure most of it would come off without too much effort! Although, I don't want to give myself any more work or expense than is necessary.

I have a plasterer coming in to re-skim the entire room, but I don't want all my hard work to be in vein (i.e. skimming over dodgy walls!)

btw - the house is a victorian stone construction

Thanks for any help

Mike

Reply to
Mikey C
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Trouble is, once you start pulling off loose plaster, you very soon end up back to brick everywhere ! I would inject some watered down PVA into the dodgy plaster through several small holes and see it that shores it up enough. If the wall / plaster bond is poor this can solve the problem. If not, you've lost nothing. If replastering, you can dry-line or do undercoat plaster yourself, leveling off with battons etc, and just use the plasterer for the skim coat. Simon.

Reply to
sm_jamieson

Thanks Simon,

I think I better stop pulling down the plaster! I will give your idea a go.

Cheers

Mike

Reply to
Mikey C

It's quite therapeutic taking it off, but the clearing up and disposal of it is not so appealing.

Reply to
stuart noble

Tap it, if it sounds hollow then it's not bonded to the wall. You might be able to stick it back on by running diluted PVA behind it but ideally it needs to come off. Be careful as you remove it as the plaster/wall bond is obviously weak. Stress it too much when pulling off the loose stuff will make the duff bit spread...

Reply to
Dave Liquorice

I would suggest: Remove any plaster that moves if you press on it. Remove large areas which have lost key (you can hear they're no longer bonded to the brickwork if you tap them). Don't bother with small areas like this though.

When you remove an area, the adjacent area will normally lose key too, so if you are too enthusiastic, you will strip it all off. When you have stripped a patch, paint the edges and the join with the wall with copious well watered down PVA to stablise it.

If you've stripped areas back to brickwork, that's a bit more than just a reskim. If the plasterer fixes these whilst he's there to do the reskim, timing would dictate that only gypsom scratch (under-) coat could be used (anything else would require coming back another day to do the reskim). Be very sure the walls are not suffering from any form of damp in the case of using a gypsom scratch coat.

Reply to
Andrew Gabriel

If I did the scratch coat before the plasterer arrives, what would be the best material to use?

Reply to
Mikey C

That's open to debate, and depends on things we don't know such as how much the building routinely moves around, and also what finish coat plaster you're going to have.

If it's going to be skimmed with standard gypsom finish coat, you might as well use a gypsom based scratch coat providing the walls are dry. Bonding coat is the norm (or Browning would probably work, but I'm told everyone using Bonding coat nowadays.)

Gypsom plaster will wick moisture, so you can't use it in contact with a damp wall. If the wall is damp with no realistic prospect of being dried, I use cement/lime/sand as a 1:1:6 mixture with a mortar waterproofing additive. This prevents moisture wicking through to the finish (top) coat.

All of these are quite hard and not suitable in the case of a building which is routinely moving around, for which you need a lime scratch coat and finish coat. That's a much more specialist job and longer process, as lime takes a very long time to set compared with gypsom.

Reply to
Andrew Gabriel

I'm hoping that my house stays pretty still! Although, there is one patch with some penetrating damp due to a crack in the outside rendering.

This crack is due to be repaired soon along with repainting the entire house. Although, this is unlikely to be done before I need to plaster and is only a small area. I assume sand and cement will be Ok for this area and gypson for the rest?

The skim will be standard gypson

Thanks

Mike

Reply to
Mikey C

Had a similar issue when I lived in a 130year old house, with dodgy lumpy plaster, great fun but never ending removing the dodgy old plaster.

Eventually I gave up, severly PVA'ed the wall to stop further plaster coming off and either dot and daubed plaster board to the wall with drywall adhesive on the brick external walls or battened and plasterboarded the old horse hair, plaster and lathe internal walls. Also battened and plasterboarded the ceiling to hide the "impossible to fix as the house is moving crack".

I also used plaster board with 1" of insulation on the external walls as walls had no cavity and were noticably colder than other internal walls.

Reply to
Ian_m

Victorian houses generally move a bit, as they mostly have very shallow foundations made of bricks and at best very soft mortar. This sits on soil and soil moves.

common indication of minor movement. These houses are designed to be ok with it, whereas modern builds are designed not to move in the first place.

Really you can skim & patch with anything and get a result. But... cement & gypsum dont cooperate with minor movement, and being stronger than the stone it tends to be the stone that breaks when seasonal movement happens, so you can get some structural damage. Then theres damp, cement is more likely to cause damp, etc etc. Really you should use lime, anything else can cause damage in the long run. If set time is an issue a small amount of pozzolan gives a light quick set so you can move on with the work. Best not to use cement as a pozzolan though, it can cause premature failure sometimes.

NT

Reply to
meow2222

Very few victorian houses were designed: at best one can say that houses that have lasted were built well enough to lat,which isn't saying much, or that houses that were built well enough to last were based on other houses that already had lasted.

Total bollocks. Cement will stop damp..getting in, which is good, or getting out which is bad.

Unless you want to build a swimming pool.

Really you should

Yawn. same old bollocks from the 'man from teh museum'

Before you lstet to Meow, you have to work out what this proerty means to you. Its it a work of heritage that you want to preserve in its orginal condition, with chamber pots, coal fires and a pump outside for water? or is it just a piece of victorian crap which was all you could afford,and you are working on a tight budget to try and turn it into modern dry warm comfortable accomodation.

Victorain houses stayed dry largely beacuse they burned coal, had draughty windows and doors and had chimneys. The moment you seal one up, you have problems.

They are hugely energy inefficient, badly built, and mostly ugly, and frankly if one could afford it should be torn down and replaced.

Otherwise your best bet is to simply build a modern house inside the old victorian shell. Line the thing with waterproof materials to let the damp go OUTSIDE through the crumbling brick and porous lime mortar , then line it with insulation, and make new walls over, then arrange proper regulated ventilation and heating.

With luck Meow will see it from the street, and never realise the only thing victorian about it is what you can see from the outside.

YOu aren;t probably old enough, but some of us had to actually live in 'victorian' houses as the average not well to do Victorian did. Uncomfortable, musty, damp, dusty, cramped, cold, no water, outside toilets, and rain stains down the walls and icy draughts as the wind whistled through the un sarked slates and un sealed sash windows.

And hand loading a ton of coal a month for the one source of heating.

Reply to
The Natural Philosopher

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