Cracks in Plaster: Whats causing this?

Updated: Dec 18, 2019

Cracking can occur when your house expands throughout the seasons. When the house expands and contracts it puts pressure on the brickwork (and subsequently plaster) eventually showing in the form of crack.

There are a number of variables that can determine the cause - indicating minor or major problems. We would advise that If the crack is larger than a hairline, or previous cosmetic repairs have failed - you should contact a structural engineer or surveyor for professional advice.


1) Change in moisture

A common cause for cracking is often related to moisture. Whether water has seeped in through the roof, or the floor above the affected ceiling - the combination of moisture and temperature can play a part. As the temperature changes, the expansion and contraction can place stress on the surface area and result in cracking.

2) Weight

If the crack relates to a ceiling, consider the room or space above this room. It could be possible that this area is bearing too much weight. For example, an upstairs bathroom and utilities. If not installed with all the necessary measures, this could lead to sagging and consequently cracking.

3) Construction Works

If other building works have been carried out in the property (usually above the effected room) eg flooring installation or roof repairs - It is not uncommon for cracks to occur when disturbing joists/ beams.

4) Poor workmanship

If the right precautions were not taken upon installation, this can result in cracking. At Rains Plastering we always ensure:

  • Renderers mesh is applied

  • Ceilings are reboarded where necessary (and installed securely)

  • A bonding agent is applied to any weak spots

Failure to carry out the above could result in small cracks showing through

6) Structural Issues

Larger cracks in your walls can indicate structural or foundation problems, we would always advice seeking professional advice before attempting repairs.

7) Property Location

If your house is located to a busy road, or train line - vibrations can result in movement of the groundworks and as a result form cracking.

Making a cosmetic repair on a crack

At Rains plastering we take every measure to prevent cracking from reoccurring.

  • Remove any loose plaster inside and around the crack.

  • Tie the crack together with a staple gun or similar tool

  • Apply PVA to the entire wall and crack, Allow to dry. Filling the crack with PVA with strengthen the wall.

  • Apply scrim tape over the crack and PVA again if its a high suction wall.

  • Apply two coats of multi finish.

The best way to prevent cracking on the interior of your house would be to use renderers mesh in the plaster. This is a 1m wide roll of mesh which is applied to the walls and ceilings when plastering. This gives the plaster a fighting chance when your property expands and contracts. We would always recommend you use renderers mesh when any internal plastering works are being carried out.

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