# Forum Home Renovation Plastering  Removing old cornice.

## munruben

Is it difficult to remove part of the old cornice.  I have just installed a new kitchen and new bulkheads above some cupboards and of course they need to have cornices around the bulkheads. I have bought the new cornices to match the old ones which are quite fancy and deep. Now where the bulkheads meet the wall and the old cornice I need to mitre the old cornice with the new and create an internal corner. I have figured the best way for me to do this would be to cut out a small section of the old cornice, say about 300mm so I can join in a small section of new cornice with a simple but joint where the old meets the new and with the mitre cut on the other  end for the angle of the internal corner against the bulkhead. I hope I have made this clear.
So what I need to know is how do I remove the old section of cornice without damaging or removing part of the ceiling or wall so the new cornice can be fitted.

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## wheelinround

Removing can be the fun part the experts may have better ideas
Like rip it off and replace the lot. 
I have used a spatula like the ones used for icing cakes thin and long with enough force it can separate the bond unless its Liquid nails 
Make a template prior removal John as often all doesn't go well :Annoyed:

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## Rod Dyson

I *would not* cut it back 300mm, as then you have to match a mitre as well as a join. Joins are much harder to match. 
Even though the cornice looks the same, often it comes out of a different mould that is slightly different. Slight differences may be apparent in a join where they are not so apparent in a mitre. 
To cut the mitre you need to use a stanley knife and be patient while cutting away. 
To mark where to cut measure how far from the wall the cornice projects on the ceiling, then mark this measurement on the cornice by measuring out from the corner along the ceiling edge of the cornice.  
Then with a pencil draw a line directly from that mark to the bottom corner. This will give you an indicater where to cut.  
With the stanley knife make a cut as deep as you can through this line, err on the side closest to the wall as you can trim easier than fill, then cut in a v along that cut from the wall side. Continue until you cut all the way through. 
I normally then cut a mitre on a spare piece of cornice and hold it up to see how it matches then trim as requried untill you get a perfect match. 
This takes 20 minutes or so but is wll worth the effort! 
Cheers Rod

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## munruben

Thanks guys. So Rod you are saying to cut the mitre on the existing cornice and mitre the new cornice up to that. I will give that a go. I see your point about the joint that would have to be pretty good if I cut it back 300mm. 
 Okay Ray, so what do I do if they have used liquid nails?  Start praying.?  :Smilie:  
Will catch up with you later Ray. got your messages ok.

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## Rod Dyson

John, cut the mitre on the existing cornice first, then trim that to match a properly cut mitre that has been cut in a mitre box on an off cut of cornice that is easy to handle.   When you have it fitting nicely you cut your full length and it will also fit just as well. 
When you cut a free hand cornice institu like that you will never get the cut right the first time.  It is better to under cut on the first attempt then trim as required to get the right fit. 
Cheers 
Rod

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## Lexi01

> I have used a spatula like the ones used for icing cakes thin and long with enough force it can separate the bond unless its Liquid nails

  Hi John,
How did you go removing the old plaster?  Did you use the advice posted (above)? I'm about to remove a room of cornice and had the same idea to use a thin spatula-like tool to break the glue... 
I'd be interested to see if it worked.

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## Agnes

Hi all, I am new on this site, my name is Agnes and I live in the UK.
We own a 100 + something old Victorian, very small, detached, single walled, Irish quarry workers cottage.
Before we purchased the house the former owners had glued some Polystyrene coving 
between the ceiling and wall in the hall, up the stairs and landing, probably to hide cracks where wall meets ceiling.
We are trying to get it off, but have not had big success without ruining the plasterboard of the ceiling and walls. 
Does anyone here know of a trick to remove this without the big damage to walls and ceiling? 
If you do, please post an answer to me, as we are desperate to get it off, but without the extensive damage that the removal does.
We intend to replace it with proper wooden or plaster coving, but the removal of the Polystyrene leaves large bits that take large bits off the wall with them when we try to remove them.
If you possibly can Please give us advice.
Best regards.
Agnes

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## gpkennedy

The cottage sounds great.  One hint when removing any cornice is to cut into the plaster with a sharp blade both below and above the cornice. What this does is to minimise damage to the ceiling and wall plaster. The cut should be more than a light score. It should be deep enough to cut through the paper face of the plaster.  I have made some assumptions here.
Good luck.
George from Melbourne OZ

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## Greg Hudson

G'Day.
I had to remove a whole pile of cornice + 2 art deco ceiling roses (which were out of character) and tried using a reciprocating saw to do the job, but it was difficult because I had to bend (flex) the blade to get it parallel with the wall. 
I gave up, and purchased a BOSCH PMF 180 E to do the job (after watching a professional using one here when he was installing new floorboards under existing skirting / base boards). His was a Festool brand - cost over $500 ! 
Basically, it is the same as what doctors use to remove plaster off people's arms / legs when they have broken them. The blade vibrates left / right very fast, and slices through plaster like it's butter.   See:  PMF 180E Multi 
The angle of the blade is adjustable, allowing you to get into really tight spaces, and because of the z shape, you can zoom along parallel to the wall or ceiling, eating away at the cornice cement used to hold them up - without causing any damage to the wall itself. 
From memory, I think it cost about AU$150 (in 2010) but the replacement blades were like $50 each !!! No way I was going to pay that, and ended up grinding new teeth using a Dremel with a cutting wheel. It only took about 10 mins, and now it looks like 10 vampires teeth in a row  :Redface: ) 
Regards, Greg.

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## r3nov8or

> John, cut the mitre on the existing cornice first, then trim that to match a properly cut mitre that has been cut in a mitre box on an off cut of cornice that is easy to handle.   When you have it fitting nicely you cut your full length and it will also fit just as well. 
> When you cut a free hand cornice institu like that you will never get the cut right the first time.  It is better to under cut on the first attempt then trim as required to get the right fit. 
> Cheers 
> Rod

   When reading the early parts of this thread, I thought the suggestions would go along the lines of matching internal corners of skirting board. That is, to mitre your second piece, and then with a fine blade and tooth saw (e.g. coping saw) cut away the mitred 'remains', slightly back-cutting to ensure a snug fit with the first piece.  
The advice wasn't so, but I'd give that a go, as it means you don't have to touch the old cornice at all.

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## CPE W&C

The way Rod explained it is the only way to go in my opinion. Anyone who has been in the game for 20 odd years has done hundreds of these cuts, and as stated, more often than not the new cornice isnt a perfect match. Its a pain in the bum but worth the extra effort. I sometimes use a key hole saw depending on the cornice as well, but can be a pain and pull out hemp/glass. You can burn the hemp off to 'clean' the mitre but not on the fibreglass made cornices of today...

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## r3nov8or

I'd still go my way. It's another of the many 'tried 'n true' methods in it's own right, just one usually done around your ankles rather than above your head. And there is no possibily of wrecking the original cornice (possibly flakey and best left alone) as it is not being cut into. I'd need a rock solid reason not to try.

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## CPE W&C

> I'd still go my way. It's another of the many 'tried 'n true' methods in it's own right, just one usually done around your ankles rather than above your head. And there is no possibily of wrecking the original cornice (possibly flakey and best left alone) as it is not being cut into. I'd need a rock solid reason not to try.

  Just make sure you score the original cornice where the mitre will be, otherwise youll be back up there in 2 months repairing a crack :Smilie:

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## Handyjack

As Greg has found, and I would have suggested, a multi function tool could be the way to go.
Different brands are available, Ozito, Bosch, AGE? and Fein. Prices vary with brand and blades that come with the tool from about $99 to >$500. A cordless variety is also available.
Like any tool practice will improve the quality of the cut. Scraper blades are also available which might be all you need.

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## Rod Dyson

> Just make sure you score the original cornice where the mitre will be, otherwise youll be back up there in 2 months repairing a crack

  Yes I agree with this.  Really scribing is NOT a good way to to do this job.  I would much prefer to take my time and cut a mitre into the old by scoring with a trimming knife until all the way through.  The rough cut hemp etc helps bind the cornice adhesive in the mitre preventing cracking.

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## r3nov8or

> Just make sure you score the original cornice where the mitre will be, otherwise youll be back up there in 2 months repairing a crack

   Fair enough. But I might have to do it just to see how long it lasts.  :Smilie:

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## CPE W&C

> Fair enough. But I might have to do it just to see how long it lasts.

  Also, scribing would be pretty much impossible on a more decorative cornice such as victorian/corbel/federation type. Should be easily done on scotia type cornice though. Roses, bells and bows etc have a pretty straight forward profile. 
When you do it reno, put a picture up :Wink:  Ive never tried it to be honest, although i have thought about it from time to time, especially when joiners cut their kitchen bulkheads around the cornice and you have to cut a 45 mitre and cut the cornice off at the bulkhead as well!

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