Can you paint over chalk covered walls?

Can't you wash it off? Never seen such a thing.

As in kids just went to town and chalked the entire wall? I'd try to wipe it down first and use some sandpaper to get off as much as you can before you paint.

Please give us a bit more info! How did the chalk get all over the walls? If it was the kids--the chalk should wash off! If there's another reason-let us know so you can get much better solutions!

Is it all different colors? Then it's too dusty to just paint over -vacuum and brush it off then,repeat, then depending how much color is left wash it down well with some dish soap and water then dry thoroughly. you will need to prime them first(to get white) then you can paint/white wash. If it's just white no problem just get loose dust off and whitewash it. (Traditionally, whitewashing wasn't actually paint, but a mixture of lime and salt. Used on adobe exteriors, wood fences, barn exteriors, and a multitude of surfaces, whitewash killed insects, neutralized germs, reduce odors, deflect heat absorption and other uses. Traditional whitewash formulas are probably not the appropriate material for interior walls, as it rubs off easily. The same soft, streaked, countrified effect can be achieved with thinned paint, either white or another muted color.) https://homeguides.sfgate.com/use-whitewash-stain-over-wall-color-32412.html

Stiff brush or push broom and someone vacuuming. Then prime with Kilz and paint.

Thanks for giving us more information to help you solve your problem. It helped immensely to try and find a solution for you! Just from what I have researched, using a stiff brush to brush off as much as you can and vacuuming all the dust off the walls and floors--as William suggested-- and then scrubbing with a stiff brush and a bucket of soapy water should remove most of it. Rinse it with clean rags and clean water. Let it dry VERY well before you attempt primer. Since it's a cinder block wall you might have to use a concrete primer or sealer. The article I am including suggests using exterior paint over the primer. Here's the info on painting cinder block walls: https://homeguides.sfgate.com/paint-cinderblock-wall-23561.html

Good Luck to you and I hope it all works out!

Thanks for giving us more information! Try scrubbing and vacuuming with a stiff brush. Then scrub with a stiff brish and warm soapy water to remove as much as you can. Rinse and wipe with clean water. Let this dry VERY well before you attempt any primer. You may have to use a concrete primer as this is a cinder block wall. The article I am including suggested using exterior latex paint over the primer. https://homeguides.sfgate.com/paint-cinderblock-wall-23561.html

Good Luck to you! I hope it all works out.

If you can get ALL of the chalk off your already painted walls then it should work to paint over it. if you see any color at all i would use primer.