| About Plaster Products | This page gives a brief description on manufacturing and fitting. |
| Cornice |
All the Cornice manufactured is made using Quality fine casting plaster and re-enforced with Hessian, along with two 10ft X 3mm wooden lathes that runs along the top and bottom edge of the Coving which gives it the strength needed. Some companies make cornice with two mixes of Plaster per length as this sometimes helps to keep the the Hessian away from the face of the Cornice, though this is not really important as when the cornice is dried or painted you can't see it anyway. A two part mix can sometimes cause problems when fitting such as the first coat of plaster breaking away from the second coat, for example, sometimes when fitting you may need to bend the cornice slightly to make it fit tightly, if so, you can risk parts of the pattern dropping off.
| One single mix can also makes the Cornice much stronger and lighter. Fire surrounds can be made with 2 mixes, as they don't need to be as flexible as other plaster products. |
|
If you are fixing Cornice yourself for the first time, Its probably easier to let it dry out. Though fitting as soon as the Cornice has been made gives you much more flexibility.
|
All the Cornice's are fitted with adhesive, and small drywall screws into each length with a cordless drill through the wooden lathes of the Cornice and into the plasterboard of the room, as some cornice's can be heavier than others, the screws will just sink and grip into the wooden lathe of the cornice when fitted, This is useful as you don't need to wait to remove the nails while the adhesive sets, because the screws have fixed it then the adhesive sets later. If you do this yourself you have to keep the screws well clear from cables and pipes. If the cornice is dry it can crack around the screw hole. Most fitters find it much easier to fix cornice when its just been made, its much more flexible. If the traditional hand made cornice is in stock or unused for too long it can lose its shape and may be unusable.
Ceiling Roses
Ceiling roses are also made from a single mix. The large ceiling roses are fitted with adhesive and long drywall screws into the joists, the surface is first sealed with watered down Polly bond PVA, ( though this isn't needed for all jobs ) and then scratched with a knife to help form a keyed surface, If the ceiling rose is a larger one ( over 600 mm ) its best not to use adhesive alone but also get some screws through the edge of the rose and into a joist, or a piece of wood placed in the right place above the plasterboard. even with smaller roses its best to put a few screws into the rose just through the plasterboard, this will help while the adhesive sets. All the ceiling roses have double Hessian for strength, so the screws just sink through the plaster and into the Hessian.
Everyone casts plaster products differently, and everyone has learned how to fix from different people, I trust where my knowledge has come from, When you buy Cornice, you should always use the instructions recommended by them, and not by what you read here, as some Cornices don't even have wooden lathes or Hessian, so adhesive is the only fixing method for those types of cornice.
