Repainting after water stains

[Tringa]

A few weeks ago we had a major water leak and a number of the walls and ceilings are water stained (as in the photo). I think I know the answer but thought I'd check on here before I redecorate.

Am I correct in thinking I'll need to use a specialist paint, such as Zinsser Cover Stain, before repainting with ordinary paint to prevent the stain from showing through?

Thanks

Dave

PS I was the cause of the water leak! I used the basin in the bathroom in the loft extension and left the tap on. The plug wasn't in but the inflow was greater than the drain could cope with. The water then flowed into the bedroom, through the ceiling to the bedroom below and through to the ground floor. I was not flavour of the month for a while

 

[ecoleman]

Is that drywall? Is it properly dry?

Drywall can take ages to dry out fully depending on how wet it got. I'm no expert but if you paint over it with a paint that will prevent the stain from showing through, you just lock moisture in.

 

[Tom_the_great]

Morning Mate,

Yes 100% Stain blocker (one designed for water stains not generic stains) I would advise something like this:

https://www.johnstonestrade.com/product/advanced-stain-block-primer

proven its worth, however couple of things to note A: ensure the walls are 100% dry don't rush it. B: Even though the one I suggested is solvent based (for a reason) it will come with a smell so ensure its well ventilated area.

This can be over coated with any water based emulsion no issue.

Regards Tom.

 

[Mr Bump]

I would defo agree with let dry out more as much as possible and then paint with stain block

 

[Tringa]

Thanks for the replies.

The wall is plaster on brick and feels completely dry. Although I said this was a few weeks ago, I've just checked and it happened eight weeks ago and every surface stained by the water feels dry now, but it did take a long time before the smell of damp disappeared.

Dave

 

[Mr Bump]

you might want to also wash the wall with anti fungicide as well

 

[Nod]

Thanks for the replies.

The wall is plaster on brick and feels completely dry. Although I said this was a few weeks ago, I've just checked and it happened eight weeks ago and every surface stained by the water feels dry now, but it did take a long time before the smell of damp disappeared.

Dave

Should be pretty dry by now but might be worth getting someone with a damp meter round to check for you (or BUY ONE YOURSELF) (check a known-to-be-dry wall and consider that as a datum for the previously damp one). A decent paint designed to cover stains will probably have a fungicide built in. Cover 18"+ beyond the extent of the staining and give it as many coats as the tin says.

 

[Mikesphotaes]

I always use Dampseal.

 

[sirch]

If it's dry and stable ordinary oil-based gloss paint works well as a stain blocker

 

[Nod]

If it's dry and stable ordinary oil-based gloss paint works well as a stain blocker

Oil based undercoat is easier to cover with other paints (emulsion doesn't stick to gloss very well.)

 

[Tringa]

Thanks again.

Dave