Painting over water stains

[davereid1]

With the bad weather we had recently I had water leaking into one of my bathrooms which has left water marks down one of the white walls. I sealed where the water was coming in and I am confident it will no longer be an issue.I attempted to paint with white emulsion not once but twice until someone told me you need to put an undercoat and them emulsion to cover water marks, which I have done. As this is now around 4 coats I have put on it has left the wall very blobby and uneven and some of the water marks are still showing. I feel if I just apply another coat it will make it even worse. can someone let me know what I need to do here before I add fresh undercoat and emulsion.

Cheers Dave

 

[sparkwright]

I have found that undercoat/oil based paint will show through emulsion for a few weeks, until everything dries out nicely.

Also, did you let the undercoat dry before doing the emulsion?

 

[emilybronte]

Wait until the wall feels dry (in the bathroom) then apply a coat of Zinsser Coverstain over the affected area before re-emulsioning. It should do the trick.

This stuff:

http://www.decoratingdirect.co.uk/viewprod/z/ZINCS/?gclid=CJDWz7Kdnr0CFZHJtAod4AYASw

 

[davereid1]

Thanks for the replys.

So what I done was waited until the water stain had dried.

I then put one quote of emulsion on, let is dry noticed the stains were still there. so put another coat of emulsion on marks still there.

I then put on a coat of undercoat a week or so later and then put on a coat of emulsion a few days after this.

so the wall now looks very lumpy and patchy.

so yous reckon put another coat Zinsser cover stain on top of all this?

I was thinking I would need to scrape the wall to get rid of all the coats I applied and start again with an undercoat then emulsion.

what do yous think?

Dave

 

[dcdec]

You need to thin the undercoat and apply with a mini roller, a brush leaves a heavy coating. You could just sand it back and start again, but if you go back to bare plaster apply thinned emulsion first, then the coverstain then top coats. Spread the paint out with the mini roller to avoid a build up of paint.

 

[davereid1]

dcdec cheers,

I think I would be more comfortable sanding back and starting again.

Would you use a sanding block or a scraper to do this?

You mention thinned emulsion, what do you mean exactly?

sorry for basic questions but my lack of decorating skills is nil.

Dave

 

[dcdec]

Just use a heavy grade aluminium oxide like p90 by hand or on an electric sander (a block is fine if you prefer) and then a light grade of say 240 just to smooth it out. Bare plaster is thirsty so thin emulsion with around 25-30% water to use as a sealer/primer, plus you don't really want an oil based coating going straight onto bare plaster.