Hi I have a house that is 12 years old and am starting to see the rafters outline through the drywall. Is this a problem? What can I do with this? Thanks moe

Don't understand this one. Drywall hangs from ceiling joist. You should not see the outline of joist. Do you mean that you are seeing the joints of the drywall or the outline of the tape?

Hi when looking up at ceiling I can see dark lines in the drywall every 2' where the joist would be. It is darkest near the wall and up about 2' also at the top about 1' this is in a vaulted ceiling. Hope this makes sense. Thanks moe

The best that I can guess (and it is just a guess) is that you have a moisture problem. Could be condensation or could be roof leak. If joist are getting wet the moisture might be telegraphing through drywall. Bet you have a flat roof.

Hello,
I agree with Harold. If you can see dark lines at the joists you have a moisture problem. I would have it checked for mold ASAP as this can cause serious health issues.
Mike

Yes, sounds like a moisture problem. Go in the attic and check it out, make sure your vents are not blocked too.

Thanks everyone,I will get up there and check it out.

I have the same problem on my vaulted ceiling and found the answer. This is common in cathedral type ceilings. When the temp drops outside the studs and rafters conduct cold to the warm inside of the home forming mild condensation. The dust particles in the home begin to stick to the drywall where the drywall meets the cold wood. Over time dark lines become visible. You can try washing but usually you will have to repaint. The only way to prevent them from recurring is to reduce the indoor humidity in cold months with a dehumidifier. Also keep the air filters in your heating system maintained. Hope this helps.:)