[peter49]

I noticed some brownish marks on kitchen ceiling where their were cracks in the plaster.house is 100 years old and has always had cracks in the ceiling.I chopped out the cracks and filled them in,painted the whole ceiling in moisture resisting paint[2 coats] and it still shows trough but even worse now.what can I do to stop this.

[ma0641]

What is above the kitchen? Brown stains are typically noted with water leaks.

[peter49]

I do have a shower above but the stains are well away from it by about 3 foot, I've sealed the shower again

What is above the kitchen? Brown stains are typically noted with water leaks.

Many thanks for your answers and suggestions,I will try some of them out.

What is above the kitchen? Brown stains are typically noted with water leaks.

I've tried wickes stain cover and its done the trick, which suggests that it was the nails making the stains when I filled the cracks.

[peter49]

What is above the kitchen? Brown stains are typically noted with water leaks.

There is a shower to the left of the stains but when I chopped out the cracks, I chopped out the cracks all over the ceiling even the ones that had no brown marks,filled them too and painted but even those cracks went a bit brown.could it be the filler reacting with the nails what the plaster is attached to as its wooden nailed slats on the ceiling with plaster over it as its an old house.

[joypulv]

Yes to moisture causing rusty nails that hold on the lath (wood slats), but probably from the shower, not the spackle or joint compound.
Water can trickle across the ceiling before settling in a spot slightly lower than other spots.
Another cause of brown stains (about 3" across) is dead mice, but you would find a corpse.

[smearcase]

Try stain blocker paint such as Kilz. You may need moisture resistance for the future but you need stain blocker to cover the stains from the past and possibly several coats over several days.

[ma0641]

Kilz or BIN, shellac base, not latex. If stain reoccurs, you have a water issue.