old adhesive showing through new emulsion -Gardz?

[TheRedGuy]

Hi there,
Have made a diy error of painting 2 coats of matt emulsion onto ceiling and yellow patches now showing through. I did sugar soap aftet stripping paper and removed residue but there were yellower parts that wouldn't come off- didn't scrape off either
I painted 1 coat of dulux matt then noticed the patches, I then bought some dulux supetmatt trade and put a thick coat of thst on to no availl
Could I use zinnser gardz over my fresh emulsion to seal this then repaint to save having to strip off the paint and sand down?
Thanks

 

[LJW61]

Any oil based undercoat applied to the stain will block it..When dry just emulsion again (zinssers pricey if youre not using it a lot)

 

[TheRedGuy]

many thanks,
it may be worth me investing in some gardz as I have th rest of the house to decorate too with years old woodchip in every room and ceiling. it may come in useful.for something!

thanks again