There are numerous reasons why the plaster along the exterior walls of your home will crack and make the interior walls look very ugly. It is important to determine the cause of any cracks you find so that you can repair them effectively. Some of the major causes of these cracks are listed below.
1. Structural cracks
Structural cracks, as the name implies, are caused by structural weaknesses in a building that are further worn down by certain conditions, such as the bathroom shower. A steam shower or a steam room cabin must be properly fortified with tiles.
The most important structural cracks include:
o Settlement resulting from inadequate or improperly located footings, use of undersized or improperly spaced members, missed bracing, or shrinkage of wood
o These cracks are usually large and well defined, extending along the surface and through the plaster.
o They can start near the corner of a door or window, or go up and down the corner where two walls meet, or along the joints between the walls and the ceiling.
2. Map and shrinkage cracks
Poor workmanship and the use of poor quality plastering materials are the main causes of what are known as “map cracks and” shrinkage cracks, that is, shrinkage in the plaster. There are ways to distinguish between these two types of cracks in plaster:
o Cracks in the map are usually caused by an incorrect bond between the plaster and the base
o They are less noticeable than structural cracks and go through the plaster, but do not extend completely along the surface, as is the case with the latter.
o They are formed by a series of cracks that extend at various angles and span areas generally 6 inches or more wide
o Shrinkage cracks, on the other hand, resemble map cracks, except that the cracks themselves and the areas they enclose are much smaller.
o They differ from map cracks in that they do not go completely through the plaster and are generally limited to the finish coat.
o Careless workmanship is usually the cause of these cracks
o Steam from a sauna can expand these cracks; an infrared sauna unit is the best way to do it
3. Loose plaster
Sometimes the keys or clasps that hold the cast to the base break or loosen, causing the cast to bulge and crack. On ceilings, around plumbing, bathroom fixtures, and kitchen fixtures, it often hangs in this condition for a long time before falling off, being held together by hair or fiber in the plaster. Occasionally, the nails or fasteners used to hold the batten in place can corrode and break, allowing the portion of the plaster that covers the loose batten (s) to warp and crack.
Tools needed for repairs
For small holes and cracks, a small diamond-shaped masonry trowel or wide-bladed putty knife, for plastering larger areas, a masonry trowel and a shallow pan.
Materials needed
o Plaster of Paris or commercial plaster for patches
o A small amount of ordinary glue if necessary
o Clean water
Mix the plaster
o All mixing boxes and utensils must be clean and clean water from your glass sink, bathroom vanity or bathtub should be used in the mixture.
o Special care must be taken that no remains of set plaster remain in the mixing box.
o The water must be placed in the mixing box before the dry plaster is sifted into the water.
o The mixture should be shaken well to dissolve all lumps.
o It should be of such a consistency that the caulk can be picked up with a wide blade knife and forced into the crack or broken into the wall
Using plaster of paris
If only a small amount of fresh plaster is needed, plaster of Paris can be used alone. Plaster of Paris sets very quickly. If using without retarder, only mix a one-time amount that can be set in 10 minutes or less.