I've noticed some lines in the plaster ceiling of my dining room that I believe are the joists above, but they're running perpendicular to what I expected. The thing is, I don't see any support beams down in the basement. Can anyone shed some light on why this might be the case? I'm thinking about skim coating the ceiling, but I'm unsure if I need to consult a structural engineer first because of these seemingly sagging joists. Here's a link to an image for reference: https://imgur.com/a/IIh7Nn2
3 Answers
When you say 'running the wrong way', what direction did you expect? Double-check the joists' alignment. Also, remember that plaster ceilings were often attached to furring strips, which could run perpendicular to the actual joists. That might explain what you're seeing!
What you're seeing could actually be furring strips that secured the ceiling boards, not the joists themselves. Older homes often have quirky setups that aren't usual by today's standards. If you're looking to skim coat, it might be a better idea to just take down the plaster and put up new drywall. That way, you can fix any underlying issues too!
Yeah, those might not be the joists—it could be that the furring strips have fallen down or something similar. In older houses, the joists might be oriented differently than you expect. If you want a nice flat ceiling, you could consider ripping out the old plaster for a fresh start with drywall. It makes it easier to address any sagging conditions and gives you a better base for finishing.