Plastering Guide Barry
Plastering Guide
Plastering is a DIY task that can often turn into a nightmare. Plastering is a skill that can only really be mastered with a lot of practice. This is especially true with "professional" plaster. This is usually more difficult to mix correctly, sets quicker and unless you really know what you are doing, can drag off the wall easily. DIY plaster has been formulated to solve many of these problems, but it is still important to understand the basics of plastering.
Plaster Types
Professional Plaster
Gypsum Plaster is the choice of the professionals and is usually applied in two coats. The first coat, the undercoat, is applied to about 10mm thick, and scored to provide a key for the second layer. The second player, or skim, should be applied to around 3mm thick in a single layer. If working on a particularly absorbent surface, a HSB (High Suction Background) undercoat plaster might be used. Specially formulated Finish plaster can also be bought for skimming plasterboards.
DIY Plaster
As previously mentioned, DIY plaster has been made to overcome some of the difficulties of pro plaster. DIY plaster comes in two basic forms; Repair and Finish, and is readily available in pre-mixed tubs or ready-mix bags.
- Repair plaster, also sometimes called one-coat plaster, is very easy to apply and can be used in thicknesses of up to 50mm. Repair plaster is especially good for filling wide and deep holes in walls such as those left when a pipe has been removed. Repair plaster needs to be "keyed" to give the finish plaster something to adhere to.
- Finish plaster is used over repair plaster to give a smooth finish for painting, papering or tiling. It can also be used directly over plasterboard or simply to smooth existing plaster. Finish plaster should only need to be around 3mm thick.
Plastering
Make sure you have the right tools before you start. You will need: Plasterers Trowel, Hawk (small, flat board with a hand) and a Straight Edge. Load the hawk with the mixed plaster and carry it to the wall. Scrape a small amount onto the trowel and spread it onto the wall in a sweeping arc. Never hold the trowel flat to the wall, keep the blade at a slight angle and let the plaster squeeze through the gap between it and the wall.
Repeat this until the area you are plastering is covered. When the plaster has dried out slightly, you can use the trowel to smooth it out. If you are plastering a small area, fill it with the repair plaster in the same way and then use the straight edge to level it off. Hold the straight edge against the wall, and move it over the plaster in a side-to-side motion.
Finish plaster is applied in basically the same way. Just ensure the plaster is not applied too thickly. Smooth off the finishing plaster with the trowel held flat. As with the repair plaster, this is best done when the plaster has dried slightly. Plasterboard can be skimmed with finish plaster, or the joints can simply be covered with Joint Tape and the nail holes ...