We are just finishing up (cross our fingers) our first Wisconsin winter in our new (to us) home and the other day notice something strange along the exterior walls. Roughly 4 ft up from the floor a horizontal line is visible that continues down the exterior wall. If you run your hand down the wall (From top to bottom), you can feel a slight bulge right where the line is. It seems to be at the seam of the drywall.

The house is roughly 40 years old. There are no cracks in the anywhere on the drywall, which leads me to rule out a foundation issue. Could this be bad mud/taping/hanging job the builder? or cold weather related? or something else?

  • Standards may not have been so high 40 years ago, or we both got the wrong guys doing mudding then, or perhaps the mud of the era has some very long term shrinkage. I do both nails and seams when I get around to painting a room. Anywhere I haven't they are all quite visible.
    – Ecnerwal
    Commented Dec 22, 2015 at 4:02

1 Answer 1


A typical horiontal seam for drywall occurs at 4ft. Usually its the best seam because the 2 long edges (of a 4'x8' sheet) are usually tapered, making a blended seam nearly perfectly flat.

Fixing this depends on how perfect you want it to be.

Nearly perfect: rough up paint 15" above and below bulge. Using bulge as a guide, put down general purpose joint compound above and below with a 12" taping knife. You are building a ramped area that will fool the eye, because it extends over 24"

When dry, lightly sand with fine grit sandpaper blocks. Shine light along wall from above. If no prominant shadows emerge, paint and enjoy.

If not, recoat and resand. I've never had to go beyond +/- 12" to hide a seam.

Is the wall flat? No. Is it not noticeable by casual inspection? Probably.

Perfect is a whole 'nother chapter.

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