Why Is Your House Paint Failing?
Posted on June 30, 2020
If you’re here, it’s likely because you’re exploring options for having your home repainted. Maybe it’s just time for a new look or routine maintenance. For far too many people, the need for house painting is the result of mistakes from previous painters. It probably wasn’t intentional, but if people aren’t paying attention to a variety of critical factors, even the best paint, applied by experienced professionals, can fail.
So, what makes house paint fail?
We’ll dig into more specifics below, but the primary trouble areas have to do with temperature, humidity, and the condition of your siding. Let’s dig deeper…
Siding Temperature
Professional house paint has a temperature “sweet spot” where it works the most effectively, sets and dries properly, and offers the best protection for your house. If the siding is too cold at the time of painting (generally below 50°F), or too hot (above 90°F), the paint simply can’t dry properly.
This temperature window includes a period of time after painting as well. If temperatures drop significantly after sundown, the cool air can damage the paint before it has a chance to create a protective barrier, and similarly, the heat of the midday sun in warmer months can have the same adverse effect.
Internal/External Humidity
Just as temperature affects paint’s ability to dry and do its job, so does humidity both inside and outside your home! If the weather outside is too humid, the water content in the paint might not be able to evaporate effectively, which leads to non-uniform drying that can result in cracks and peeling.
The humidity inside can also cause trouble, especially on higher levels of multi-story structures, as hot, humid air gathers in upper levels, in bathrooms, and in attics. This is often most noticeable on the outside walls of such rooms, and even around electrical outlets and upper level windows, where the internal humidity is trying to escape through the siding.
If your home doesn’t have a proper vapor barrier, this problem is compounded further.
Siding Condition
This is perhaps the most common reason house paint fails, but the specifics are many…
You want your siding to be clean, appropriately dry, and in good shape when painting starts. If the wood is saturated from rainfall, it likely needs a few days of dry, sunny weather to dry. On the opposite side of the spectrum, unfinished wood exposed to weeks of 
punishing sunlight will have a layer of degraded wood fiber at the surface, and won’t hold paint nearly as well. Fortunately, a good power washing or sanding can remove this degraded layer and prepare your unfinished siding for more effective painting.
Beyond moisture content and sun exposure, other issues with siding can cause paint to fail as well. Decayed, rotting wood won’t hold paint and needs to be replaced. Siding improperly installed, installed directly over insulation, and bad sealing can also force moisture to pass through the siding, leading to damaged paint, stains, and other moisture-based damage.
Even siding that is simply dirty or too hardened can cause trouble with adhesion and uniform drying. For dirty siding, a power wash or some work with a stiff bristle brush will make things better.
The hardening of your siding can happen from mill glaze. This is when the manufacturing process of close-planing or milling a smooth surface compresses wood fibers. This leaves something of a glaze on the surface of the wood, making it harder for paint to stick. Sometimes this is done intentionally to protect wood during the manufacturing process, but it can also be an accidental result of processing and temperature. This problem can also be solved with gentle sanding or power washing!
House Paint Variables
As you can see, house painting involves a huge variety of factors. Because every house is unique, each of these variables can exist in varying degrees of severity. The expert team and contractors at CertaPro Painters of Metrowest takes each of these concerns (and much more) into account every time we begin a job. If your house isn’t ready for painting, we’ll make sure everything is in good shape before we ever lay down the first coat. We ensure quality service, and results from the initial painting quote to the final walk through of the project!
If you have questions about the condition of your home, need an assessment about repainting, or need anything else, don’t hesitate to contact CertaPro Painters of Metrowest today at 781-296-6044!
Looking for more Home Exterior tips? Check out our other home improvement articles!
