Yellow stain coming through newly painted wall/ceiling

[edl123]

Hi,

I have recently painted a room (wall and ceiling) in white emulsion. The paint looks perfect, but after a day or two, yellow stains start to come through where there was an old partition and on the joins where the wall has been replastered.

It doesn't matter how many coats i use, as it always makes its way to the surface.

I have used a sealant paint which seems to have worked to lock the stain in. unfortunately you can now see where the sealant is used instead of the yellow, but at least it is the lesser of two evils.

Any ideas what may have caused the yellow, or how to avoid it, as I have another 4 rooms to do and don't fancy going through all this every time.

It is a victorian building that has been vacant for 12 years and not been decorated since the 70s.

Any help much appreciated.

 

[Diyisfun]

I think you are supposed to use gloss paint, not a sealant.
I have read about this before. I think
I dont know the cause of the stain, reckon we will be told soon enough.

 

[JohnD]

yellow stain is often from a water leak.

 

[edl123]

There's no leaks, but there is a chance that the building is quite damp as it has had no heating for 12 years. May be a case of moving in and redecorating again in a year once the building has dried out.

 

[misterhelpful]

As said, water is the most common cause of such stains and can usually be solved with a stain blocking primer (many available but Zinsser CoverStain is regarded as one of the best). The stains can also be caused by underlying bituminous coatings/adhesives (many older properties seem to have something like this) nicotine and soot, amongst other things, which can bleed through new plaster skim. Damp can also leave these stains and all can usually be covered with the stain block or an alkali resitant primer.

Some stain blocks will 'flash' through your top coat of paint until dry or may take several coats to completely hide.

Out of interest, what did you use to seal the stains?

 

[edl123]

I used the zinsser bullseye. Seems to have worked, but like you say may need a few coats to cover the sheen it gives.

Can you apply it directly to new plaster?

 

[misterhelpful]

Can you apply it directly to new plaster?

There are two versions of BullsEye and both can be used on plaster but IIRC the 1-2-3 version is not so good for water stains. I'm not 100% certain but I know that one of their products is only suitable for light water stains and, as the 1-2-3 is water based, it is most likely to be that. The solvent based Bullseye is suitable for heavier water stains though.

 

[joe-90]

I prefer slightly thinned undercoat. Best for the job and cheap as chips.

 

[misterhelpful]

I prefer slightly thinned undercoat. Best for the job and cheap as chips.

Cheaper than chips these days!

 

[TheDec]

If the stains are not caused by either damp or the ingress of moisture, then a thinned oil based undercoat will suffice. Yet if there is any doubt that the staining is due to the ingress of moisture then you should apply an Alkali Resistant Primer.

Dec

 

[edl123]

cheers for the help guys. hopefully this does the trick.