How do I sort this damp stain on the ceiling?

[ihatealldiy]

Hi
Recently I had some leak in the shower upstairs as one of the silicon linings had come loose. I have fixed that and there's no more water leakage. But it has left me with this problem on the ceiling in the room below. How do I go about it?
1. The old paint comes off in layers and if I continue pulling it out, it may extend right across the ceiling!
2.Any way of getting a smooth finish to enable painting over it?
3. All suggestions with details would be really appreciated as I am not very good at diy. Apologies!


Many Thanks

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[nicholasdanny]

I'm no DIY expert but I would lightly sand around ther affected are and then feather in (lightly brush) some stain block paint that takes moisture and stops any further algae or staining from the damp and the when dry paint back over with the same paint as your ceiling to cover.

 

[ihatealldiy]

I'm no DIY expert but I would lightly sand around ther affected are and then feather in (lightly brush) some stain block paint that takes moisture and stops any further algae or staining from the damp and the when dry paint back over with the same paint as your ceiling to cover.

Thanks for that. I am comfortable using a stain block,etc to sort out the stain.My worry is the appearance of apparent depression on the ceiling due to the loss of thickness at the big spot. Any way to completely conceal the defect and make it even with the surrounding areas? Do I need a filler?

I have enclosed an image of something similar to illustrate what I am talking about.

 

[misterhelpful]

I can see that some of the plaster skim had come away and agree that you will need to level the surface out before painting.

Firstly, you will need to remove all the loose material back to a sound surface. You may think it will come off the whole ceiling but it 'usually' only goes a few inches past the damaged area. If you don't remove all the loose material, you will probably have issues with the edges when filling.
You could then apply a coat of stain block over the stain before applying a filler. If the area turns out to be pretty large, you could use something like EasiFill with a plasterers trowel or taping knife. This will be the easiest to sand and feather in when dry, if you are not very experienced, but other fillers or ready mixed skims are available.
Once dry and sanded, dust off and apply a mist coat of watered down emulsion before applying your finish coats (it wouldn't hurt to apply another coat of stain block after misting). The biggest problem is trying to get the surface to match the texture of the surrounding paint and you may find it will take a few coats to get it looking even.