CRACKS IN CEILINGS

There can be many reasons for cracks occurring in ceilings—it could be the sagging of old joists, natural flexing of the structure, or something heavy being dropped on the floor above. Hairline cracks can be hidden by applying a new coat of textured paint or paper, but wider ones must be filled before you redecorate. If you come across a crack running the length of the ceiling, there might be serious structural problems, and you should consult an expert about it.

 

In older houses, lath and plaster ceilings may have sagged; also, the old plaster may be weak and crumbly. In the more modern building, plasterboard ceilings might have thin cracks, usually at the edges. These are quite often caused by natural settlement during the drying out after construction.

 

For carrying out the work, you’ll need a filling knife and scraper, an old paintbrush, self adhesive mesh, glasspaper and block, plasterer’s trowel, water spray and sponge, a hammer, stepladders and scaffolding boards.

 

Any cracks must be thoroughly prepared, filled, and finished if the repair is to last. Rake out any loose material with your filling knife, and undercut the edges so that the filler will get a good grip. Brush out any remaining dust and debris with the paintbrush. Fill the crack with filler using the filler knife or scraper. Dampen with the sponge so that the plaster won’t absorb too much moisture from the filler. For extra reinforcement at plasterboard joins or ceiling/wall angles, apply self adhesive mesh. You could use hessian scrim tape instead, bedding it into a band of joint filler. Cover the mesh with jointing compound using a rubber bladed applicator.

 

Cracks at nailheads are nearly always caused by condensation. Chip off any damaged plaster and apply rust converter compound before filling. For larger cracks or holes, use a ready mixed DIY repair plaster, building it up in layers as you proceed. Allow each layer to dry before applying the next one.

 

For cracks at wall/ceiling joins, use decorative coving. Fix polystyrene coving with pre-mixed special cement. For gypsum plaster based coving, use special coving adhesive. You can buy coving which has its own mitring device for shaping the ends to fit corners.

 

Remember that your work is above you, so wear protective goggles when cleaning out the cracks. Make sure that you use a strong stepladder—for large areas you can use two stepladders, with a scaffolding board in between. As with any job, safety should always be paramount.