We don't want to remove the (sound) wallpaper from the ceiling.. An old water tank in the loft must have leaked in the past, leaving brown stains on a white ceiling. Also tar from an old chimney has leached through staining some patches.
Hello,
Yes, this will seal old dried water stains no problem.
However, RE the tar stain, the oils from the tar have the potential to block the stain from sticking to the surface very well.
If the tar stain is on the surface you would need to wipe as much of the tar off. A white spirit or sugar soap may help to break down the oils in the tar. You can then gently sand the area to remove more of the tar and create a suitable key for the paint/stain sealer.
If the tar has bled through from somewhere else then 1st it is advisable to make sure the leak which caused the initial leaching/bleed to be fixed.
You can then wipe with white spirit/sugar soap and gently sand to create a key.
As the tar contains oils it may be better to use a primer, sealer and stain killer. This is better suited for sticking to more difficult surfaces.
Thanks for using Q&A
Answered by: DGIFF
Date published: 2020-12-23