Older houses may be full of charm, but they can also hide a lot of problems. If you've decided to decorate one of the rooms in your house, then you should check the plaster over before you paint or paper the walls. If the plaster is old, it may be failing and in need of replacement.
How can you tell if your wall plaster is okay or not?
Tap the Walls
Go around the walls you're going to decorate, and tap them in various places. If the plaster is in good condition, it should sound hard and dense — this should be like tapping on brick or concrete.
If your plaster is not doing so well, then it will sound hollow when you tap it. This may happen all over a wall or just in certain areas. This generally means that the plaster is no longer firmly attached to the wall behind it. It may have come loose or may be deteriorating.
Look For Damage
You can also tell if your plaster is in good nick from the way it looks. While minor crazing or small cracks aren't always a sign that the plaster needs replacing, more significant damage tells you that the plaster isn't doing its job so well any more.
For example, larger cracks aren't a good sign. Also, if you've taken old wallpaper off the walls when you were preparing to decorate and some clumps of plaster came away with the paper, then this is also a hint that the plaster has deteriorated.
Test the Plaster
While plaster isn't as strong as brick, it should form a solid surface that is resistant to damage. If an area of plaster looks basically sound but you're worried that things aren't quite right, then test it out.
Take a screw or nail, and try to push it into the plaster. You shouldn't be able to get the screw or nail into the plaster without tools. If it sinks in easily with just a push, then the plaster isn't in an acceptable condition.
If this happens, you'll also often make a bigger hole than you expected. The plaster around the screw or nail hole may blow out if the plaster is soft or unstable, leaving you with a much larger depression in the wall.
If you aren't sure whether your plaster is fit to decorate or not, then call out a plasterer to look at your walls. They can tell you whether your plaster needs repair or replacement.