Wood casement around your windows swell and contract with weather changes and humidity in the house. This causes the plaster in the lower right and lower left corners of your windows to crack and shoot the crack downward. Sometimes it’s a hairline and sometimes a small chunk.

Why does plaster crack around windows?

If your home has walls that are plastered, then straight vertical cracks typically form when the plaster expands in humidity and shrinks as it dries. These are normal and are usually the type of cracks you’ll find in a new build property.

Why is there a crack under my window?





The most common cracks under your windows are shrinkage cracks, which are often vertical and appear a few months after constructing your foundation. As concrete dries, it shrinks and begins to crack, usually under your windows. Noticing shrinkage cracks in foundations is commonplace.

Why does drywall crack under windows?

Cracks form due to stress placed on the seams. These cracks tend to occur around high-stress areas like windows, door frames, and corners. This stress can come from many sources. Temperature fluctuations can cause the drywall to expand and contract creating stress that cracks the seams.

Should I worry about cracks in plaster?

Absolutely, cracks in plaster walls are a normal part of owning a home and usually nothing to be concerned about. In fact, many new houses are prone to cracks while the house settles over time.

How do you fix crumbling plaster around windows?

take out all the old plaster, pva the area to repair and apply multi finish, if its only a small area, use polyfilla. you would need find out if the plaster is crumblling due to water damage first if so you would need to re-seal the window from the outside first.

How can you tell if a crack is structural?





As the name suggests, structural cracks occur because of poor construction sites, overloading or poor soil bearing.



Telltale signs of structural cracks in your foundation are:

  1. Stair-step cracks.
  2. Cracks on foundation slabs or beams.
  3. Vertical cracks that are wide at the bottom or top.
  4. Cracks measuring 1/8″ in width.


What causes hairline cracks in plaster?

Often, a wall or ceiling could have been freshly plastered and the hairline cracks appear due to shrinkage in the plaster. In older properties, hairline cracks can begin to occur where lath and plaster walls and ceilings are present which loses its integrity overtime.

When should I be worried about wall cracks?

Jagged or diagonal cracks indicate that the foundation may have shifted or sunk, or another problem has occurred, such as the deterioration and collapse of supporting wood members due to termite damage. Likewise, cracks wider than one-quarter inch indicate a potential problem with the home’s structure.

How do you stop plaster from cracking?



The first prevention tip is stopping the plaster or render from drying too quickly. This means avoiding plastering and rendering in direct sunlight or where there is a strong wind. The premium time for plastering or rendering in the warmer months is early in the morning, as it is less humid at this time of day.

Is a crack always subsidence?

Not all cracks are due to subsidence – fine, hairline cracks are usually nothing to worry about.

How do you permanently fix cracks in plaster?


Quote from Youtube video: And then we're gonna add a piece of mesh tape right right and then on top of it we're going to run another pass of joint compound.

Why is plaster coming away from wall?



Over time, plaster may delaminate or become detached from the surface beneath. In the case of stud walls and ceilings, timber laths are fixed between the studs or joists and the plaster is pushed through the gaps between the laths. Rotten laths can result in plaster sagging or bowing.

Can condensation cause plaster to crumble?

If the condensation issue is not treated, it may result in peeling paint or plaster. If the walls appear wet and the plaster damaged, then this is likely to be a result of condensation.

What causes plaster to peel off walls?

Excessive moisture can cause the top layer of plaster to peel up. There are typically 3 coats of plaster applied to any plastered wall: the scratch coat, the intermediate coat, and the top coat or hard coat.

How do you fix crumbling plaster walls?

Quote from the video:
Quote from Youtube video: And all I need to do is cut that as close as I can to the plaster you can see I'll just pull out on the wire mesh got to be careful with this might recommend using some gloves for this.

How do you paint cracked plaster walls?



Mix up a small batch of setting-type joint compound and use it to fill the crack and all the holes. Smooth the wet compound with a trowel; then, as it begins to harden, wet it and smooth it again. After the compound sets, sand the area lightly, then prime and paint.

Can you paint directly onto plaster?

You can paint straight onto/over plasterboard in most cases, you simply need to cover the joints and any holes created by your fixings first. Being able to paint directly onto the surface of the new wall is convenient and saves time and money. You can also plaster over painted plasterboard at a later stage.

Should I leave windows open after plastering?

Yes it is expected when plastering is completed all the water in the plaster has to go somewhere while the plaster dries out. Either get some windows open ajar or get a dehumidifier in (severe case).

What happens if you don’t mist coat new plaster?

Top tip: If you don’t let the plaster dry and apply emulsion paint to wet plaster, it’s likely to crack and peel off. Painting new plaster that’s completely dry can also leave you with uneven brush strokes. So, the next course of action is to create your own mist coat paint.