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Why Does Paint Crack and Peel?
When interior paints blister or crack, the trouble sometimes can be attributed to poor-quality paint, however in most cases the trouble is actually due to poor surface preparation or the wrong methods of paint application.
When peeling occurs on interior walls or ceilings, the first thing you must suspect is that it's some sort of moisture leak inside of or behind that wall. If this happens on an painted outside wall, there might be moisture seeping in via
small cracks or other openings in the siding or exterior masonry, or the water could be coming in through gaping joints around window frames and other trim on the outside of your house. Remember that the leak may not be immediately opposite the place where interior peeling is detectable. Water can work its way into a wall, dripping down or traveling sidewise along a beam for some distance before really soaking into the plaster on the wall or ceiling of the house. In the same method, a roof leak at the top of the house can sometimes cause ceilings on stories below to blister and peel since water travels down through the wall until it hits a horizontal ceiling beam on the first floor. In most cases you’ll be able to tell whether or not water is the real cause of the trouble due to the characteristic staining on the plaster.
Even after a leak has been repaired, blistering and peeling may sometimes continue after the wall surface has been repainted. This is because the damage wasn’t properly repaired prior to the application of the new coat of paint. The old plaster could be crumbling or is loose and unless it is correctly patched, new paint applied to it will keep on peeling off.
Paint peeling sometimes happens around the edges of metal casement windows due to condensation. As warm moist air coming from the inside condenses on the cold metal frame, the gathered moisture tends to seep into open joints between the plaster and the metal, filling the plaster and working its way out through the paint, causing the paint to blister and peel in the process. To avoid this, install storm windows when possible and put on caulking around both the inside and the outside of the frame.
In older homes and buildings, another common cause of paint peeling is the accumulation of several layers of paint over previous brittle coats that no longer can bond. As every additional new coat of paint is applied the situation gets worse until finally the whole section start to crack, loosen fall off or peel. When this happens, all the old coats of paint must be taken off with paint remover prior to the application of the new paint finish.
Another more common cause of paint peeling in kitchens, bathrooms and work areas is the failure to clean and prepare the surface thoroughly beforehand. Each can of paint has instructions on the label which advise that the finish be applied only over a clean, dry surface, yet this warning is often ignored. Paint applied over a dirty, greasy or glossy surface won’t dry or adhere properly. Often cracking and peeling will occur exposing the layer of paint under it. For semi-gloss and high-gloss paints it is recommended to lightly sand or rough the surface (green kitchen scouring pads work great for this) prior to washing it down to get good adhesion.
This problem is especially noticable around fireplaces and radiators, since wall parts near these units are frequently a lot dirtier than walls elsewhere in the home. Wash all walls prior to painting and never apply paint when the wall surface or radiator is still hot. Brushing paint on a heated surface causes untimely drying, making it almost impossible to get a good bond with the wall surface.