# Forum Home Renovation Plastering  Will cornice stick to painted surface?

## barney118

I havent put my cornice up yet but I undercoated the gyprock is this a problem with cornice not adhering?
If not I may as well paint the wall and then put up the cornice? is this ok?

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## ah76

Assuming you're using cornice adhesive, and the undercoat on the wall is the usual stuff, then it will be fine. 
I did the same thing with a cornice 2 years ago and it hasn't fallen down!!

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## Rod Dyson

> Assuming you're using cornice adhesive, and the undercoat on the wall is the usual stuff, then it will be fine. 
> I did the same thing with a cornice 2 years ago and it hasn't fallen down!!

  It will be weaker no doubt better undercoat than the final coat though. 
I would put it up then after go around and put a screw in every metre or so and at the external corner junctions. 
The screws should be just below the surface and then filled in.   
Really it is not a great idea to put cornice up this way.  But if you do as i say it will be ok. 
We get a lot of people that have not done the job the right way and say "it is ok no problems for me"  Not having a shot at you ah76 just a comment in general. 
The trouble is with every thing there are risks involved, not every job is going to have a problem but a large % will.  If you have some movement then you will have a problem. 
The only way to do something to minimize risk is to do it right IMO.  This is why we have Australian Standards to work to, they protect the consumer to ensure the risk of problems is minimized by using the best practice. 
Cheers Rod

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## barney118

Thanks, I have used the prep coat so I will put up the cornice first.

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## ah76

I agree with your comment Rod, and I should have mentioned that the wall I did this on is basically a floating partition with an overall length of 2mt. Also, movement isn't a problem here ( probably why it's stayed put and hasn't cracked) 
You'll be pleased to hear when I altered the shape of our bathroom, the cornice was done the correct way!!!   
Cheers, 
Andrew.

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## bloodyricho

rod is spot on but an old gypies trick is to cross hatch the painted area with your Stanley knife xxxxxxxxxxxxxxxx like this all the way along. the cornice cement will grab a whole lot better. screws are generally a last resort. if the room gunna shift it shift under the cornice......

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## barney118

Who would have thought of that xxxx! I have also been told to give it a sand to rough it up. Await now for the cornice to turn up, 40L/m 9 @ 4.8 long have one spare just in case I measure or mitre wrong. for the sake of $25 a length good insurance.

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## Godzilla73

G'day, 
Another tip i was told, is to hold the cornice up on nails to support it without adhesive, mark along the top and bottom with a pencil then score along the line and 10mm in from that again with a knife and peel away the top layer of paper this leaves a clean surface to stick too. 
I've done it at my place as i was going over the top of 55mm cove on walls with a few coats of paint by the previous owners, it's worked a treat, been going through room by room renovating for the last 5 years and no cracks so far. :2thumbsup:

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## Rod Dyson

> G'day, 
> Another tip i was told, is to hold the cornice up on nails to support it without adhesive, mark along the top and bottom with a pencil then score along the line and 10mm in from that again with a knife and peel away the top layer of paper this leaves a clean surface to stick too. 
> I've done it at my place as i was going over the top of 55mm cove on walls with a few coats of paint by the previous owners, it's worked a treat, been going through room by room renovating for the last 5 years and no cracks so far.

   Yep that will work have done this myself in small runs where i didn't want to put screws.  However on a larger area it is too time consuming for me.

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## Godzilla73

> Yep that will work have done this myself in small runs where i didn't want to put screws. However on a larger area it is too time consuming for me.

   :What he said:  My times my own tho, do you try and get the screws into studs? I'd be searching forever if you do, random stud spacing doesn't even come close to describing it... :Doh:

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## barney118

I can see the studs as I am 60mm short with the sheets, nails are in position ready to go. Same goes with the ceiling battens a screw every m or so?

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## Rod Dyson

> My times my own tho, do you try and get the screws into studs? I'd be searching forever if you do, random stud spacing doesn't even come close to describing it...

  I use longer screws that get into the plate much easier than finding studs.

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## CPE W&C

I always do both once the plasterboard has been undercoated... 
First cross knife XXXXXXXXX, then a screw every 1200mm or so and on external corners. Just make sure you dont cross knife below the cornice line :Wink:

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