Posts Tagged ‘temperature’

Weird Cracks

March 24, 2020


I have just finished stripping off wallpaper that I hung 12 years ago. The walls beneath are in perfect condition.

Except that, along just about the full height of just about every seam, I discovered these hairline cracks.

What is very odd is that the cracks have not made the wall unstable, and no material has pulled away from the wall (as often happens when you have layers of incompatible materials that will not adhere to each other – do a Search here on “delaminating”).

I believe that my original prep 12 years ago was to skim-float the walls and sand smooth. Then I wiped off the dust with a damp sponge, then followed with my favorite primer at the time, KILZ Original oil-based primer.

My thought is that the KILZ, or possibly the underlying joint compound, has separated due to tension put on it by the wallpaper seams, possibly shrinking and expanding over the years due to minute fluctuations in humidity and temperature.

Why that happened I don’t know.

This past year, I’ve had opportunity to remove wallpaper from several jobs that I hung as far back as 20+ years ago. All were over the very same original prep conditions. But none showed these little hairline cracks.

I always like to understand why something happens. That way, you have the potential to prevent it from happening in the future.

Not that I’m particularly concerned in this case. The tiny cracks have not created any problems, and the wall is not unstable.

I felt perfectly comfortable hanging the new paper right on these walls – however, I made very sure that no seams of the new paper landed exactly on top of those cracks. That would eliminate the chance of any stress put on the cracks by the new seams potentially causing them to weaken and pull away from the wall.

Potential Trouble Brewing

July 7, 2019


What you see here is a bit of rubbery latex paint and texture that has peeled away from the wall in this powder room. The surface underneath it felt gritty and dusty and porous. I had the feeling that if I had tried, I could have peeled all the paint off the wall.

This is not good.

This paint is probably peeling because of a combination of poor quality materials (cheap paint), improperly prepared surface (inappropriate or no primer, not removing dust from the wall, incompatible coatings (latex over oil based, not sanding or deglossing a gloss paint before repainting), climate fluctuations (humidity, temperature), stress on the wall (pulling off a piece of tape), or more.

All this is not so bad under paint, because paint just kinda sits there on the surface. But wallpaper actually puts stress on the surface beneath it, as it dries and pulls taught. Over time, fluctuations in humidity and temperature can exacerbate that, causing the paper to expand and contract ever so slightly, and then put tension on the wall where the seams fall.

This can result in not just the seams coming loose, but in the various layers inside the wall actually delaminating and coming apart from themselves.