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.  

HOLES AND CRACKS IN WALLS

Most walls in a home will develop a crack, or cracks, at some time, including yours and mine. For smaller ones, it’s fairly easy to repair it, a DIY job, but if there’s there’s a large area of damage, it’s probably best to replaster the whole wall, which might entail some specialist help. Whatever you do, don’t rush this kind of job—a bit of patience is required for this work.

 

You’ll need a filling knife, plasterer’s trowel, hand water sprayer, plastic spreader, an old, wide paintbrush, sanding paper and block, battens, masonry nails, and hammer.

 

There’s a wide range of materials on the market, which is a bonus for the DIY  enthusiast. Use general purpose filler for smaller cracks and holes, and to finish, use a layer of fine surface filler.For the larger areas, use DIY repair and skimming plaster. 

 

Before making a start, remember what I said about patience—it’s needed from the outset, not just when things seem to be going wrong. Make hairline cracks bigger using a Stanley knife or similar, so that the filler will grip. Make sure that you brush out any loose material, and spray lightly with water. Use the plastic spreader or a filling knife to force the filler into the cracks and holes. Even off the edges the edges by stroking the filler with the knife in all directions.

 

For a larger hole, cut back the edges to the sound plaster, and ensure that you remove all the dust. Apply the first layer of filler up to about 5mm (1/4 in) thick, and press in well. Add more thin layers as necessary. Use a wide plastic spreader for the last layer, making sure it’s flush with the wall surface.

 

If you have to do an area  which is over 1 square metre, you’ll have to level it with a plasterer’s trowel. Chip back any loose edges, and press the new plaster into the hole with upward sweeps. You can get rid of any airholes using a fine surface filler. Load your tool evenly,and press firmly against the surface to save you the need for sanding. Drying times recommended by the manufacturers should be followed.

 

If corners are damaged, take a  straight batten and lightly nail it level with one edge of the corner. Leave the other side of the damaged are exposed. Spread the repair plaster or filler on the exposed edge. Smooth the surface off against the edge of the batten. When the filler is completely dry, remove the batten, and position it on the other side. Apply filler as before, and smooth level with the batten.

 

To skim plaster, apply the skimming plaster with your old paintbrush, using upward strokes. Do square metre areas at a time, brushing out the plaster as you go along. As the plaster starts to dry out, smooth out the brush marks with a plastic spreader dipped in water. If you think it can still be improved upon, sand it down lightly.