Fixing Cornice

[ausdesign]

I'm about to install standard coved cornice through an extended hallway, bedroom, laundry & toilet area. I've noticed that a previous attempt in the kitchen some 5 years ago is departing company. I used a powder type conice cement mixed to a paste placed along the top & bottom internal curves & then secured with the occasional plasterers nail.
Does anyone have any hints or an alternative method.

[silentC]

Nails shouldn't be necessary at all. You might put a couple in to hold it up while the cement sets but pull them out afterwards. Maybe you mixed it too dry or it had started going off before you put it up? You have to move quick, it goes off like a rocket.

[Bluegum]

I found that mixing to about the consintancy of tooth paste works best. spread it evenly ovet the top and bottm of the cornice and then get it into position. A couple of small nails as C has said and let it set.

[Jacksin]

I dont know if this will help but a cornice fixer once told me, cornice cement will stick to almost anything except painted surfaces. Sooner or later it will part company.

A small bead top and bottom with nails tacked alongside the cornice, till it goes off, then removed seems to be the norm.

[silentC]

True it wont stick to paint. Tear off the paper first if you're applying it to a painted wall/ceiling.

[ausdesign]

Thanks.
Thinking back I did paint the walls & ceiling first as I was waiting on the cornice to be delivered. - Good idea at the time !

[echnidna]

If you can get some "no more tradesman" (liquid nails) behind the loose cornice it should stick it up permanently. Use the water based stuff so you can clean up ooze out.

[Mars]

Hi

I put my cornices up about 6 months ago, and have noticed that they are releasing slowly,The walls were painted before i moved in and also the walls and ceiling are concrete, Whats the best way to reinstall? I like the idea of tearing off the paper, though the cement didn't stick to the wall at all, it stuck to the cornice good.
What do you think i should i do?

[Bluegum]

Hi mars and welcome to the forums. Is there any way that you can get a sharp edge under them and lift them out? Depending on how much cement you've got behind them. I've never had to pull them out only put them up.

[Mars]

Hi Dave and thanks

The cornices that are up there now have all got cracking ubderneath, i can get then off no problem, and i will do to refit them in, i wanto to know, whats the best way in putting them back on the wall, do i sand the paint back to scuff a surface? or sugar soap? or can i get a stronger adhesive?

[echnidna]

liquid nails

[Skew ChiDAMN!!]

Even though it loos like seperating easily, I'd still lightly score the wall (& ceiling) plaster at the joint with a stanley knife before removing the cornice. All it needs is one small section to have glued properly to tear some paper off the wall. :rolleyes: Best to mark the cornice when removing to ensure each piece goes back in the same spot.

The scoring'd also give you a reference mark to sand above, back to the paper surface, before reaffixing the cornice as per normal. The usual wiping of the joint with a damp sponge to remove excess plaster will also refill any over-exuberant scoring. ;)

[galvarez]

Peter<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
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A couple of pointers from a plasterers perspective.<o:p></o:p>
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Firstly, in established (that is, not new) kitchen areas, putting up cornices often poses problems because of the presence of a film of cooking oil on the wall that prevents proper cement adhesion. As mentioned in an earlier post, cleaning of the cornice lines with sugar soap will help. To be on the safe side and ensure the cornice does not loosen in the future is would be advisable to mark the position of the studs and ceiling joists (these should be visible) before cornicing with a pencil and pinning the bottom (and possibly the top) edge of the cornice in place with a couple of screws.
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In contrast to previous comments, I’ve never found cornice cement not to stick to painted surfaces. I can think of various reasons why you had problems. Maybe the mix was made too runny. Maybe the brand of cement. In any case, screwing the cornice up will remedy this as once the cement goes off it sticks to almost anything.
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On tiled walls cornice cement does not readily adhere. One handy trick that I use in this scenario is to place masking tape along the bottom edge just above the cornice line. The cornice cement will adhere to this.
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Finally. Cement rendered walls can be a problem. If cornice has loosened in this instance, it may be an idea to put the cornice up with cornice cement, use nails on the bottom cornice edge to hold in place while the cement dries, and also to place plastic plugs (‘spaghetti’) through the cornice’s bottom edge and fasten with screws. May seem drastic but will ensure that the cornice will stay up long-term.

Hope this helps and wasn't posted too late.

All the best
Gus

[julianx]

the gyprock supplier that I use in brisbane sells pre mixed cornice cement in tubes like no more gaps. It works well but is an expensive way to do it if you have lot to put up. It sets a bit like no more gaps so you can't sand it like regular cornice cement.

[Mars]

Hi

My situation is painted rendered walls, and so i think i might just play it safe by just putting them on with liquid nails, sugar soap and then glue.

The Big question now is, The existing cornices that look like they wont come off ( put on originally with cornice cement) should i take them off and start from scratch of hope for the best and leave them on?

[silentC]

I’ve never found cornice cement not to stick to painted surfaces
Yeah, sure it's stuck to the paint. How well is the paint stuck to the plasterboard though, and for how long? Personally, I don't like gluing things to paint. That's just me though....

[Jacksin]

Yeh cornice cement will stick to paint for a few years then let go.

If you dont believe me (and a reputable cornice fixer) feel free to ignore it and re-install it years later.