Wall Efflorescence area - painting

[Ref786]

Hi there,
A little portion of my wall had Efflorescence as per attached pics. I found the water was coming through the roof tiles which I got fixed. So I would like to know how I can paint the affected area now. Just cleaning and filling the damage area and repainting will do the job?

 

[JohnD]

It looks pretty bad. Scrape off the paint to expose the plaster so it can dry out dry. Brush off any new crystals. It will not dry much in winter. If the room is warm and dry you can speed it up by setting an ordinary room fan (not a fan heater) to blow on the wall, which will accelerate evaporation. Ventilate the room so the damp air can escape.

DO NOT TRY TO WASH EFFLORESCENCE OFF WITH WATER

When you paint it, use a non-vinyl emulsion such as Dulux Trade Supermatt, which is porous and allows damp plaster to dry out. You can repaint it with normal paint when the wall is fully dry (which may take a year).

 

[Ref786]

@JohnD thanks for your reply. I guess area is fully dried as I got the leakage fixed in mid of June 2024. So as per your instruction all I need is to clean the area and paint it with any water based paint ? Please let me know if I am missing anything. Many thanks

 

[JohnD]

Scrape it. There is likely to be a loose damaged surface. You can use a very fine sandpaper if it is scabby (coarse or medium will leave lines that show through paint). Don't wet-wash it.

A matt emulsion is most forgiving. If you can't afford Supermatt (comes in 5litre tins) you might be able to get something cheaper, it must be branded as "suitable for new plaster." White is always cheapest.

Apply one or two mist coats thinned with water before the final coat.

 

[Ref786]

@JohnD very appreciated! Thanks a lot

 

[Koolpc]

I would scrape it all off and leave exposed for another few months. Let it dry out thoroughly. Dont rush it.

 

[michealangelo]

I would leave it alone after scraping off the dodgy areas

Put heating on plus ventilation till spring

Then, very importantly .......prime the affected areas with alkali resisting primer ......zinser guardz etc ......BEFORE ANY repainting

2 full coats , allowing drying time to the full

It wouldn't harm you to coat the entire affected with alkali resisting primer

 

[michealangelo]

@JohnD thanks for your reply. I guess area is fully dried as I got the leakage fixed in mid of June 2024. So as per your instruction all I need is to clean the area and paint it with any water based paint ? Please let me know if I am missing anything. Many thanks

You are missing a suitable primer like guardz

 

[michealangelo]

It looks pretty bad. Scrape off the paint to expose the plaster so it can dry out dry. Brush off any new crystals. It will not dry much in winter. If the room is warm and dry you can speed it up by setting an ordinary room fan (not a fan heater) to blow on the wall, which will accelerate evaporation. Ventilate the room so the damp air can escape.

DO NOT TRY TO WASH EFFLORESCENCE OFF WITH WATER

When you paint it, use a non-vinyl emulsion such as Dulux Trade Supermatt, which is porous and allows damp plaster to dry out. You can repaint it with normal paint when the wall is fully dry (which may take a year).

I would advise a primer before repainting to deal with the efflorescence

Zinser guardz or similar

Agree with everything else