Paint cracking is a common problem, usually quite visible in older homes with a lot of layers of paint. It looks like a flattened spider web of cracks in the paint. The similar term crackling is used to refer to a fuax finishing painting technique to that is meant to resemble cracked paint found in older homes.
In modern days, while building the walls we have now we use a moisture-and mold-resistant wall panels called Sheetrock (created by US Gypsum) commonly referred to as drywall. 8′ x 4′ is the conventional panel size outside of large construction. In older days it was one of two things, gypsum board or plaster and lathe. Gypsum board is similar to drywall however it wasn’t as convenient as drywall. They were both available but gypsum was the choice for a long time.
Plaster and lathe is an old building art now quite visibly dying off as new and improved techniques have rendered the art disadvantageous. After the studs (the skeleton of the house) are laid the interior wall portion takes form and the lathe would go up. Lathe is smaller pieces of wood at about 1″ wide and 4′ long. Once the lathe is up next would come the plaster. They set up guides that are four feet apart and go vertically then apply two coats of plaster. This effectively creates a sheet of dry wall. Interestingly, while demolishing the walls in older homes you sometimes come across horse hair in the old plaster. This was mixed in to strengthen the plaster.
Cracking in all likelihood will not take place in newer construction. Modern day Sheetrock should be primed with water based paint. Oil may be used in spite of the modern movement towards reducing oil based paint usage due to environmental issues. The oil based paint has a long history with the artisans of paint. The makeup of oil based paints has drawbacks. Positives reside around durability and the leveling properties of the paint as it is drying. It does take a long time for oil paint to dry, in any case oil has come a long way and is competing with water based paints.
Immediate attention would not be needed with new construction concerning cracking. New construction is defaulted merely because of the amount of layers of paint that could be on the wall and when the change from lead based to oil based to water based paints occurred!
Other forms of cracking do appear, they are referred to as “alligatoring”. “Alligatoring” is given its name for a reason, it looks like alligator skin. The most banal example would be exterior homes where far too much paint has been applied through the eons and or 10 to 20 years. Even if all coats were prepped and primed properly sooner or later the chemical change in the makeup of each consecutive layer of paint lead, oil, water, will eventually create problems. If you can get past that I bet Mother Nature will eat away at the foundation of the paint just like she forms our great mountain ranges. Eventually hot, cold, sun, wind, rain and snow will wear down on surfaces and create problems.
Sometimes the only way to deal with “alligatoring” is to remove all the paint, this is a timely process which involves the use of strippers and heat guns. Unfortunately, in the long run it is more cost effective to renovate. If the “alligatoring” has gotten extremely bad, there may be suspicion that the wood is deteriorating.
Cracking starts with a certain amount of coats of paint. For extreme cases the paint also will have been through the technical changes of the years. Meaning that older paint coats, possibly even before the sixties will have amassed over time, some may even contain lead. The complexities of these paints’ chemical make up as stated earlier will inevitably interact in some way. Paint has been guaranteed now days from anywhere to 25 years to infinity and beyond. That claim may be true providing it is new construction. The case study here is numerous amounts of paint, the first err could be with the first coat! Was that even primed or prepped and every consecutive coat should be scrutinized with that perspective.
One of the most recent problems would have been the switch from oil paint to water if not primed the water based paint may not adhere to the wall. What this means is that you may have a surface of paint that just sits on top of the wall. When you paint walls with water based paint you can risk a chance of cracking. Applying new water based paint to the surface will “reactivate” the other paint. Moisture will be added to the surface and that will cause the paint to expand and contract. Old and aged paint can become brittle and the flexibilities of that paint are lost and the paint can crack. It also can bubble and whole surfaces can just fall off the wall.
One of the ways to remedy these potentials for cracks on old homes would be to go back to the old wheel. Break out the oil paint! Oil has the right properties to re-seal the substrate, water based paint are consider a soft paint and oil are considered hard.