An individual seeking to put up curtain rails in thin plaster walls can run into considerable difficulty. The walls of the past were often made with a system that is known as plaster and lath. In this type of construction, a relatively thin coat of plaster (several coats applied at different times in fact) were put over a skeleton consisting of basic structural framing elements and thin wooden strips. The problem here is that plaster is quite thin and cracks easily. Thus if someone tries to screw a piece of hardware like a curtain rail into it without going about it the right way, they can run into problems with cracking plaster or with a mount that is not strong enough to last long, causing the curtain rail to break and fall out of the wall.
Plaster or Drywall?
Most house construction that occurred after the 1950s employed drywall rather than plaster. Some people confuse the two. Drywall consists of large 4 x 8 sheets of papered gypsum mounted on studs or other framing members of the house.
As a matter of fact, drywall can run into many of the same problems as plaster when someone tries to mount curtain rails. That is to say is someone does not mount a curtain rail right, drywall is often not strong enough to support curtain rods, particularly ones carrying heavy drapes, and the walls can fracture causing the window dressing suspension to fail.
Keeping all this in mind, here are some tips and suggestions for making suspension of curtain rails work right:
Screw into Lath
If the individual is indeed dealing with an old plaster wall rather than drywall, there will be a series of thin parallel strips of wood from floor to ceiling in the wall. This is known as lath and represents the under skeleton of plaster walls. The key if someone is screwing something into such a wall is to make sure that whatever screws they are using go into the lath rather than the spaces between it. Lath is fairly strong and should support screws unless the curtains are very heavy. An individual can find this lath either with s a stud finder (see below) or simply by tapping a nail gently into the wall and seeing if it hits wood or seems to punch through into empty space. They can fill the small hole this leaves with spackle if need be. They will only need to find two spots where the rail needs to screw in so it shouldn't be too much of a problem.
Another solution, and this works well with both plaster and drywall, is to use special anchors. These anchors go into pre-drilled holes in the plaster or drywall and expand, grabbing the wall. The screws then screw into these. These work well as long as the rails and curtains are not too heavy. If there is too much weight however, the wall can crumble just as it would with screws of nails.
By far the best idea is to screw into wood. This thus involves finding with the studs or lath strips under the plaster or drywall. Then the individual can simply mark where these are and screw the curtain rail into them accordingly. There are devices called stud finders that are used to do this. Some of them work magnetically and others use more high tech means, but their purpose is to find probable areas where there is wood rather than empty space in the walls. They don’t always work 100% reliably, but they can be a useful tool.
A final idea is adhesive. Structural adhesives may be strong enough to hold the curtain rail if rightly applied. The individual simply glues the curtain rail to the wall (perhaps strengthening the installation with some anchors and screws) and this supports the weight adequately.