Why Does House Paint Peel?
December 28, 2015
The most common problem we encounter when it comes to painting existing buildings is the issue of peeling paint. Many our of residential painting projects are actually requested due to this very reason. So this begs the question, How do you prevent paint from peeling?
One of the most common problems associated with paint jobs is peeling paint. Many painting jobs are actually requested as a result of peeling paint and therefore the most common question we receive is “how do you prevent peeling paint?”
Paint can peel for various reasons and there is always a lot of different variables in play, however the only thing that really matters is that the current paint coating is losing its adhesion.
So lets look at the reasons why paint looses its adhesion
1) Moisture and Water
Moisture is the most common cause of peeling paint. This can be related to moisture created when having a hot shower or when rain is able to enter the cracks or splits in exterior timber. In our experience the most common areas in which we have had to repair peeling paint is the bathroom, laundry & kitchen. In most cases the peeling paint has been limited to the ceiling and could have been prevented by the proper coating system being applied. There can always be other reasons for causing peeling paint however excessive humidity, steam and moisture penetration will undoubtably be the major cause of peeling paint.
2) Excessive Layering
Because most ( not all ) peeling paint is limited to ceilings it then becomes extremely common that the second most popular cause to peeling paint in our experience is due to excessive layering which in turn means multiple paint coatings over the span of a number of years. As each new coat of paint is applied more weight is being added to the coating that was first applied to the ceiling, which is creating the adhesion. Over time gravity will take care of the rest and then you have the cause of peeling paint.
3) Poor Preparation
It all comes back to the preparation, before any paint is applied its important to ensure that the area to be painted is clean, dry and sound surface. Painting over dirt, grease and grim will inevitably lead to peeling paint issues in the future. Primers are designed to penetrate the substrate ( on a microscopic level )and create adhesion for additional coatings, Most times peeling paint is a result of not using the correct primer. Primers are an essential part of the painting process as they create the adhesion needed to allow for long term piece of mind.
4) Heat / UV
So we know that moisture and water can cause peeling paint but excessive exposure to heat and UV rays will also do the same. The reason why paint peels is due to the loss of adhesion to the surface, when paint is subjected to excessive heat or uv rays it can dry the paint film out which will cause the paint to loose its elasticity. When the paint loses elasticity it wont flex and move with the expansion and contraction of the building which will cause the coating to crack and split.
5) Incorrect Paint Application
We touched base on the need to use correct paint primers, by not having an understanding of the type of surface / substrate that is being painted over it can cause peeling paint. For example, if we were to have an oil based enamel and we plainly used a water based acrylic over the top ( which wasn’t a primer ) it would not adhere and scratch off. This simple concept can then be extended to nearly every type of substrate we encounter when painting, its extremely important to throughly understand the potential problems that may arise from a specific substrate and which coating should be used in which order to best maximise the additional coatings.
6) Weather and Micro Climates
Weather may not be the smoking gun to peeling paint but it will defiantly be the force which delivers the cause. Its important to understand that each house is different not only in appearance but also in the way in which it is affected by the weather. Some houses are closer to the beach which will receive more harsh winds which will also bring large amounts of salt and sand, other houses may be on an acreage which will experience an intense dry heat in the summer and very cold winters. All of these different variables for each house allow for different control methods, for example if your home has heavy vegetation surrounding the house and allows for moisture to harbour then you can bet that if you have peeling paint it will be due to the moisture that has been created via the heavy vegetation.
7 ) Old Age
Just like everything else in life, paint does not last forever. Paint is designed to protect the surfaces which in a whole make up our biggest investment. Over the life span of a coating system it will be exposed to a range of variables which will erode the coating which in turn will allow all of the above causes to create the issue of peeling paint.