If you find yourself needing to repair an area of plaster in your home, you will realise that there are many lots of options available for repairing the problem area. While the best option is to take plastering courses and learn how to repair the problem in the correct manor, there are a some other options that will help temporarily repair the damage until you learn how to fix it permanently.
Understanding Plaster
The first thing you need is to gain a better understanding of plaster. For example, because plaster is a hydration product, it is very similar to concrete. In other words, once mixed with wated a chemical reaction process begins. This process cannot be reversed and the mixture will dry and set within a certain period of time. This means that, if you don't get the timing right, you will find less than desirable results.
Considering Your Options
When you start looking for ways to repair your plaster, you will find that there are several dry powders available that are also fast setting compounds. With these products, you add water in the same you add water to plaster. As such, they will set in much the same way as plaster. The biggest difference is that the products are available with different set times so you can choose how much time you will have before starting the project. Some types of plaster can be sanded to create a smooth finish if the application to the damaged area is not as smooth as you would like. This can be very useful if you are not experienced and the finish may not be as smooth as you would wish.
Repairing the damage
Small holes in plaster are easy to repair, providing the lath backing that held the original plaster is still intact. If it is, simply mix joint compound with plaster of Paris and use it to fill the hole (the compound retards the plaster setting time and makes it easier to work with). Clean away any loose plaster and dust and fill from the edges in, working the plaster mix into and through the lath for a good bond. Do one rough, or "scratch," coat and allow it to dry, then apply a finish coat.
If you must repair a hole in a plaster wall where there isn't a backing that will hold the plaster from behind, you'll have to install backing first. Enlarge the plaster hole just enough to reveal some remaining well-anchored lath.
Cut a piece of wire mesh to fill the opening, push the mesh into the hole and hold it in place with wire ties wound around one or two dowels or sticks. Apply the plaster/compound mix in layers, allowing each to set hard before adding another.
Let it dry, then snip off the wire. If the hole is large and your plastering skills are weak, use joint compound only for the finish coat, and sand it smooth.
