How to patch water damaged ceiling plaster?

[rocketman]

A small patch of ceiling in our bedroom has been water damaged. I've removed the wet part, but not sure how much should I tear off the plaster. How do I properly fix it?

 

[MitchellMc]

Hi @rocketman,

To start, have you resolved the cause and repaired the roof where it was leaking? That's the first step. The second is to let the area dry out entirely, and this could take a full week. 

Any loose paper must be removed, and then a skim coat of plaster should be applied over the area with a trowel. Once the plaster has dried, you can sand it back flush with the surrounding ceiling. Another lighter coat of plaster might be required to smooth the surface, followed by a final light sanding. 

You'll then be able to undercoat over the area and paint.

Please let me know if you have any questions.

Mitchell

[rocketman]

Thanks @MitchellMc.

The damage has been there for a very long time and it hasn't extended, but good point that I should have it double checked.

In terms of removing loose paper, I don't think I have removed it entirely, should I use a scraper to do that?

[MitchellMc]

A scraper would be an option, @rocketman. You don't need to remove the well-adhered paper, just anything that is loose and hanging off. I'd typically just grab any loose edges and tear the paper back until it is well-adhered.

Mitchell