Lite brown marks on celling after painting.

[chrisb1357]

If it does not block water stains what would the next option be to paper over it

Chris

B&Q usually only stock International brand Alkali Resistant Primer and sometimes Dulux Trade. Unfortunately, they are probably the two most expensive versions, although well worth the money.

Leyland or Johnstones are just as good but usually a fair bit cheaper from a decorators merchants.

I'm not fully convinced that alkali resistant primer is the ideal product as it won't always block water stains, should it turn out that's what you have, but it won't do any harm.

 

[TheDec]

Mr H,

Alkali resisting primers are well known within the trade for their stain blocking properties, from simple stains such as the op has discovered, to fire damage and flame retardant applications,

With pigments containing titanium dioxide, zinc oxide, suspended within an oleoresin binder they really can't fail can they.

Dec

 

[misterhelpful]

Mr H,

Alkali resisting primers are well known within the trade for their stain blocking properties, from simple stains such as the op has discovered, to fire damage and flame retardant applications,

With pigments containing titanium dioxide, zinc oxide, suspended within an oleoresin binder they really can't fail can they.

Dec

Agreed, but as said, from my own experience it hasn't always blocked water stains. Not saying it won't in this case just that sometimes it may not be ideal.

Chris,
Water stains will still find their way through paper so you really need to ensure they are hidden before doing anything else. I'm imagine in this case the alkali primer will work, but IF it doesn't, a stainblock recommended for water stains will.

 

[TheDec]

Well in my 40+ years in the trade i've never known it fail, stange really I suppose.

Dec

 

[misterhelpful]

Well in my 40+ years in the trade i've never known it fail, stange really I suppose.

Dec

Yes, but you learn something every day - if you are willing to.

 

[TheDec]

Give it Mr H you are condeming a product that is both designed and formulated to seal these types of stains and indeed very many more, not really a learning curve is it,

Dec

 

[misterhelpful]

Er Dec, if you read my posts you would notice that I have said it usually works but in some instances hasn't. Not my fault if you haven't had the same problem.

You seem very quick to jump on anything from me that remotely differs from your opinion lately. It's a bit boring now!

 

[TheDec]

Well if thats what you think, Mr H when someone decrys a paint or primer that works I do tend to get a bit offish if I have come across a litle sharp then I apoligise. It is just that I have a great passion for this trade and I will always defend it.

Although if I feel that either the wrong advice is given or someone deems to challenge good advice I will react accordingly, if you find this either boring or annoying I apologise but thats the way it is.

Dec

 

[joe-90]

Stop wasting money on fancy primers when cheap oil based undercoat will do the job. Even hairspray will do the job.

 

[TheDec]

Problem here is that if these stains are the result of previous water damage alkalis would have formed within the skim, And sometimes although I admit they are rare an alkyd based undercoat can and I mean can fail. and that is why I advised a resistant primer.

Dec

 

[chrisb1357]

Umm i am being told 2 things now LOL.

Alkali resisting primer or Oil Based Undercoat

 

[joe-90]

They are only water marks. The water based paint reactivates the stain and it bleeds through. All you have to do is stop the water in the emulsion from reaching the stain and it's sorted. They talk some piffle on here at times. In the real world it's done with oil based undercoat.

 

[TheDec]

Chris I can understand your confusion here, I am becoming such myself, the reality here is an oil based undercoat could fail were as a alkali resistant primer won't. The only time these primers can fail is two fold either moisture is still present or they were incorrectly applied, eg they have been thinned or the stained areas were not completly covered or indeed a comination of both.

Dec

 

[chrisb1357]

Hi Dec,

I am going to go for the Alkali Resistant Primer i think even if they cost a bit more than using undercoat. I dont want to use undercoat and then find i still have to buy the primer.

I am going to apply it to the whole celling as its only a med size hallway celling.

Just to confirm its ok to paint this over the matt white paint thats on the celling.

Chris

 

[misterhelpful]

.Although if I feel that either the wrong advice is given or someone deems to challenge good advice I will react accordingly, if you find this either boring or annoying I apologise but thats the way it is.

Wasn't challenging, just offering a different opinion, hence my grievance.

As decorating has been my livelihood for the last 20 years I too have a bit of a passion for it.

No falling out intended, just thinking more than one opinion can sometimes be more helpul.