Skimming is the process by which a thin layer of plaster is applied to a wall or ceiling to provide a smooth surface. Often referred to as board finish, the amount need for a particular job can be calculated based on using 10kg to every 5 sq meters. This assumes plaster is applied to a thickness of approximately 3mm. It's worth noting that plaster should be stored in a dry place, but it does have a minimum shelf life, so bulk buying and storage might not be such a good idea unless you are using it in large and frequent amounts.
As you set about your next plastering job it's well worth cleaning the plasterboards first. Dust and dirt will create problems so a little time spent in preparation will pay dividends later. If at all possible empty the room or at the very least cover anything of value. Not only do you want to avoid damage to furniture etc, but you also want to be able to move around the room unimpeded, particularly if you're working on a ceiling which means you need the whole floor space to move around in.
When it comes to corners, they need to be properly prepared. External corners are best trimmed with angle beads. Angle beads are galvanized strips, which are simply nailed, with galvanised nails, to the boards. So long as you've taken time to square them up with a spirit level, the result is a nice sharp cover. The angle beads can be cut with a small hacksaw or tin snips but it's a good idea to use protective gloves, as the edges can be fairly sharp.
Plaster should be mixed using equal amounts of plaster to water, taking time to mix until a smooth consistency is achieved. A hand whisk can be helpful here. Once the plaster is ready wet the spot board and empty the plaster onto it. A spot board by the way, is just a board of around a meter sq; useful for catching the plaster as you work.
A small quantity of plaster should be loaded onto the hawk. Depending on your preference (right or left handed) hold at around chest height and push a measured amount of plaster onto the surface with the float. It takes practice, but you are aiming for a repetitive action which is smooth and fluid. For walls it's best to work up from the floor spreading a thin layer and then back down again from the ceiling to smooth out the plaster. A second coat can be applied as the first begin to dry a little. This coat should fill in any ridges. A clean float should be used to smooth the whole job. As the plaster starts to harden, again the float can be used as if to polish the surface. Water can be applied with a brush to help when polishing with the float and naturally fill out the smallest of holes.
This article is free to republish provided the resource information remains intact.
Shropshire Building Skills :: Shropshire's No. 1 Construction Training Centre
mail to: firstname.lastname@example.org