painting over fire damaged plaster

[faycat]

Hi

Parts of our new bare plaster walls got damaged in a fire. We have cleaned most of the soot off with chemical sponges so you can only see faint marks but there is also a candle wax stain [all wax scraped off].

Do we need to treat the stained areas with anything before we attempt to decorate? If so, before or after the base coat?

Thanks so much for any advice...

 

[confidentincompetent]

Not done any for ages but in the past, after a lot of cleaning we used thinned undercoat to seal the stains before emulsions or whatever the finish was.
Nowadays we have stain blockers like this http://www.zinsser.com/product_detail.asp?ProductID=10 or dulux stainblock. They are pricey and sometimes they do fail and need more coats of blocker than it says on the tin. But never have probbs with the undercoat

Thats progresss.. good luck.

 

[faycat]

Thanks for the info. If I used a stain blocker, like the one in your link, could I just use it to cover just the stained area or would I need to cover the whole wall and the whole ceiling [or the whole room] to get an even finish with the other coats of paint?

Thanks

 

[confidentincompetent]

You can just paint the blocker over the stained area's. Wait for it to dry. Then with the paint you plan to finish with apply this just over the blocked area's wait for this to dry (be patient here) then paint the whole wall/room.
When touching in be sure to feather in the edges (let brush run dry) so you don't leave a thick edge which will show through the finished coats.

Have fun

 

[faycat]

Thanks a lot. I feel a lot more confident now that my wall and ceiling are going to look OK.

If you have time to reply again, I just wanted to check if I should put all the coats on the affected area and wait for them to dry and then paint the rest of the wall or just put one coat of normal paint on top of the satin blocker and then paint over everthing at the same time for the final coat?

Cheers!