Cracks in plastered walls are common, and while some cracks might not need attention – others could have serious structural consequences. But how can you tell the difference?
In a nutshell, there are two groups: non-structural and structural cracking.
1. NON-STRUCTURAL cracks are not detrimental to building integrity, but they may need to be addressed due to cosmetic reasons or to take proactive steps to prevent those cracks from growing over time and eventually reaching the structural stage.
a) Crazing is a network of hairline cracks that are usually very fine and shallow and do not extend through the whole depth of the plaster. Craze cracks are of little importance, do not open and close with time, and can be covered using a good quality Acrylic.
b) Map cracking is similar to crazing except that it is usually deeper (sometimes going through the plaster). These cracks normally occur when a plaster mix with a high cement content is used or the plaster is allowed to dry too quickly. These cracks can be filled with a proprietary filler and painted over. Glass fibre tissue can also be applied during painting. A textured coating or Fibre paint can also be used to hide/waterproof these cracks.
2. STRUCTURAL cracking does affect the integrity of the building and can be caused by differential movement of the foundations, moisture expansion/drying shrinkage of masonry units, or thermal movement of the roof. Because these cracks originate in the wall and not in the plaster, repairing the plaster is ineffective. In the case of structural cracking, we would suggest calling RENU in, to establish the cause of the cracking and to recommend the best restorative measures.
