Settling of a plasterboard house or repair the occasional earthquake can speed this process.
If the lath backing is fine, you crack can mix joint compound with plaster repair of Paris for the patch.
Then prime and paint it to match the wall.
Latex paint will hide hairline cracks repair in plaster, at least temporarily.
If, plasterboard when you push on crack the wall, it flexes as though it has broken away from its support base, call a plaster specialistthe repair will involve removing the loose plaster and replacing.How to Fix Sagging Plaster Flaking and cracking plaster are relatively minor repair items, but when the plaster starts to sag, or belly out, from a wall or ceiling, it indicates deeper problems.The coverup, though, may last only a few hours or a few months.Repairing Small Cracks in Plaster, small cracks in plaster are relatively easy crack to repair, with one condition: The plaster must be firmly anchored to the lath behind.This base is usually strips of wood or metal wire mesh (both referred to as lath) that are nailed to the wall and ceiling framing.

Repairing a fringe large wall area ndungu is difficult enough, but if the ceiling is beginning to sag, working over your head with investing heavy, hard-to-handle materials is not an easy job.
Allow the compound to dry and game then sand lightly to blend the patch into the wall at the edges.
3, dampen the patch again and apply another layer of patching plaster to about 1/4 inch of the surface.6, apply another coat of joint compound with a drywall knife or wide-blade putty knife.Expert advice and detailed instructions on repairing the most common plaster wall and ceiling problems, including cracks, holes, and sagging.When it has dried a little, score the plaster with a nail, as shown at right.Gravity and the weight of the plaster exert themselves, and the first sign is often sagging, followed eventually by the collapse of the plaster surface.Plaster can also be damaged from maker the normal stresses and strains of people living in a house: holes from wall hangings, scratches from furniture, spilled liquids.(For story more about how plaster walls are built, see.What You'll Need, here are the tools you'll want to have manual when repairing cracked plaster: Utility knife, vacuum cleaner, plaster of paris or premixed plaster repair compound.Let best this dry, then apply a finish coat.You end up with a drywall surface, but it eliminates the problems of sagging, cracking, and flaking plaster once and for all.Don Vandervort, HomeTips, earthquakes are unkind to plaster walls, as evidenced by this deep crack.At this point, you may want to call in a professional.Plaster is heavy, and it needs a solid, well-anchored base to support its weight.If youre worried that much of the ceiling could come down at once, build T-shaped supports from 2 by 4s and use them to hold a piece of plywood flat against the ceiling while you work.If the lath has pulled away and the plaster is still well-adhered to it, you may be able to refasten the lath to the framing without removing the plaster.

Note: Please see the reader comment at the bottom of this page for a method of reattaching sagging ceilings using drilled holes along the crack line on both sides.
It just takes a little spackling compound to repair fine cracks, nail holes, repair crack in plasterboard and gouges in a firmly anchored plaster wall.
You can also use a simple test kit from Bunnings to indicate the presence of lead-based paint.