ᐅ How much can wood expand and contract, and what amount of movement is considered normal?
Created on: 12 Feb 2018 10:51
M
Mizit
We live in a 23-year-old Kampa prefabricated house with a timber frame structure.
For example, at the end of September, we freshly painted the bedroom on the upper floor. About 2-3 weeks ago, we first noticed these black "cracks" on the ceiling, exactly where the ceiling meets the side wall. At first, I thought it might be mold, but it was clearly cracks.
These cracks are now clearly increasing. You can really see it. In the bathroom, along this ceiling-to-wall joint, there are also noticeable grooves of 2-3mm (0.08-0.12 inches) that definitely were not there before.
We know wood moves, that’s clear. At the moment, it’s also quite cold.
But is this normal? It seems strange to us. There is a significant crack in the ceiling in the hallway as well. It doesn’t just look odd cosmetically...
For example, at the end of September, we freshly painted the bedroom on the upper floor. About 2-3 weeks ago, we first noticed these black "cracks" on the ceiling, exactly where the ceiling meets the side wall. At first, I thought it might be mold, but it was clearly cracks.
These cracks are now clearly increasing. You can really see it. In the bathroom, along this ceiling-to-wall joint, there are also noticeable grooves of 2-3mm (0.08-0.12 inches) that definitely were not there before.
We know wood moves, that’s clear. At the moment, it’s also quite cold.
But is this normal? It seems strange to us. There is a significant crack in the ceiling in the hallway as well. It doesn’t just look odd cosmetically...
Yes, that's how it is.
Carpenters often use MS Polymer as joint sealant in such critical areas. It can be painted over like acrylic, has almost no shrinkage, and offers 300–500% elongation, depending on the type and price. And this brings us to the point. It is more expensive than acrylic: $1.45 for acrylic, $9.95 for MS Polymer. Also, it is harder to work with; a wet finger is not recommended.
Carpenters often use MS Polymer as joint sealant in such critical areas. It can be painted over like acrylic, has almost no shrinkage, and offers 300–500% elongation, depending on the type and price. And this brings us to the point. It is more expensive than acrylic: $1.45 for acrylic, $9.95 for MS Polymer. Also, it is harder to work with; a wet finger is not recommended.
