What is chalking?

[Groupie]

I am in the process of building a small block wall and will paint it with Sandolin Black masonary paint. I says on tin if chalking occurrs treat accordingly. Hence "What is chalking" and can i stop it THX

[boxtops]

I think it's when the salts start drying out and showing on the face of the blockwork - my neighbours built a wall and as it dries out, there are big chalky-looking patches emerging.

[Groupie]

Thx box sounds about right to me ,Can i do anything to stop this happenning?

[AlBags]

Apert from using a masonary sealer on it .. no.
Brush it off first.

[beegeebee]

Many, many years ago when I was an apprentice, we used vinegar diluted 4 to 1 with water and brushed the wall. never failed B.

[Groupie]

Bee Funny you should say that,while working on the wall yesterday an "older" gent passed by and we started talking and he said a similar thing too you , paint with vinegar, but i as a "youngster" thought what an old wives tale.
But i shall try it now and we shall see in a while. Meanwhile "Watch this space" Thank you all.