Unless
you favour the 'rough stone wall' effect in your house, chances
are that your walls and ceilings will be plastered. In older houses,
plaster is usually applied directly to the brickwork. Newer houses
often have timber-framed partition walls clad with sheets of plasterboard,
with only a thin coat of plaster to finish the wall. These walls
will show as fairly thin or will sound hollow when tapped.
Over
time, plaster can develop surface cracks through slight movements
within the house, or it can be damaged by impact. Long hairline
cracks may also appear when the joints between the plasterboards
were not taped during installation. Accidental damage will be greater
on plasterboard surfaces, than on plaster applied directly to masonry.
Cracked
plaster is not a big problem, but it can leave a room looking neglected.
And like a broken tooth, if left untreated the problem can grow.
Cracked and damaged plaster will absorb moisture from its surroundings
and deteriorate further. It is therefore sensible to repair damaged
plaster as soon as possible and deal with cracks and fissures before
re-decorating a room.
Cracked
Plaster
If your wall or ceiling is covered in a myriad of tiny hairline
cracks, use a coat of emulsion paint to repair the damage. Make
sure the paint is well worked into the surface and covers all the
cracks.
If
the cracks are larger, they must be filled individually. Clear out
loose plaster and dust from the crack with a fine brush or a vacuum
cleaner. Mix up some all-purpose filler according to manufacturer's
instructions or use ready-mixed filler. Push the filler well into
the crack, making sure that no gaps are left, before smoothing it
to be level with the surrounding wall.
If the crack is very deep, fill it in stages, leaving the filler
to dry and harden between applications.
When
the filler has dried and hardened, sand it down to be flush with
the surrounding wall. Use a sanding block and fine-grained sanding
paper to achieve a good finish. A power-sander may be used if you
are dealing with a large area.
Cracks
Between Walls
If you live in a fairly new house, chances are that the structure
may still move a little, and cracks can appear at the joints between
walls or between walls and the ceiling. These are most commonly
filled with acrylic-based decorator's mastic, which will not crack
if further movement occurs.
Again, clean out any loose material from the cracks with a brush
or vacuum cleaner and apply the mastic along the crack. Run a dampened
finger along the joint line to create a nice smooth finish.
Leave the mastic to dry before painting over it.
Damaged
Plasterboard
Plasterboards are easily damaged by impacts and the resulting blemish
often looks worse than it really is. In fact, holes in plasterboard
can be easily repaired.
If
small and shallow, brush out any loose plaster with a soft brush
before covering the hole with self-adhesive patching tape. Then
spread filler over the tape and smooth it out. Sand down when the
filler has dried.
Patch
larger holes by repeatedly applying thin layers of filler until
the hole is fully covered. Leave each layer to dry and harden before
applying the next one and sand down to be flush with the surrounding
wall once the last layer of filler has dried.
