How to remove wall chalking?

Question

I have problem with wall chalking. I have tried to clean it with TSP like other users suggested in previous questions but it didn't really help. I want to make sure that this time paint and primer will not peel away.

Any other ideas?

Thanks

Answer 1

First, I really wonder if the chalking you are seeing is coming from a previous layer of paint or if it is coming from the actual wall surface.  Are you sure the walls were ever painted?

Drywall should not chalk like this, but old plaster, left unpainted for years, can develop conditions that will cause it to chalk.  Corrective action would depend upon the type of plaster, age, and the cause of the chalking.  If this might be the case, you need to address stabilizing the plaster before you think about paint.  You will need someone familiar with plaster to take care of this for you, as it is impossible to properly assess this without physically inspecting the wall.

If you are sure it is paint chalking, then you should be able to do this yourself.   The TSP is the right way to go.  You need to get as much of the chalking off before you go any further.  Your TSP should be mixed to the strongest concentration listed on the box, I would go a bit stronger.  Do not use a sponge for this step -- use a stiff, natural bristle brush with a handle (often called an acid brush because masonry contractors use them with acid to clean brick).  Start at the top and work down.  Spend a little bit of time scrubbing, you need to loosen as much of the chalk as you can.  

Don't forget to rinse.  Rinse while the wall is still damp with the TSP solution -- don't try to wash it all then rinse -- small sections at a time.  Do use a large sponge for the rinsing.  Again start at the top, wipe down.  Wipe, rinse your sponge, wipe again.  The sponge should come off fairly clean when you are properly rinsed.

After washing and rinsing, you should be ready to prime.  The surface should be dry, but don't wait too long as you don't want to give the surface time to chalk.

This is one of the few situations where it is necessary to prime a previously painted surface.  Again working with the assumption that the paint is chalking, not the wall surface, the previous paint is having problems.  The chalk you see is actually the pigment in the paint coming unglued from the wall.  Could be because of really cheap paint, over-thinned paint, defective paint (it does happen somtimes), or the wrong paint for the application.  Ceiling paint on a wall will do this sometimes, but I have never seen it as bad as what you are describing (based upon your previous questions as well).  The important part is the pigment particles are not properly glued to the wall.

Selection of the primer is important here.  To make sure it sticks, you need something with good gripping power but also some extra binders (glue) that will absorb the loose pigment and bond it to the wall.  Your previous attempt used a primer that has good grip, good blocking, but not a lot of extra binders.  

I would look for a good PVA primer.  You do not want something with a lot of pigment, you already have more than you need.  Many primers that are marketed to consumers as being the best have a lot of pigment so they cover well.  If you look at them in the can, they tend to be thick and cover as well or better than paint when applied.  You want a more traditional primer, which will look translucent as you apply it to the wall, a bit thinner than normal paint in the bucket.  I have never touched any of the Behr products, but my guess would be that their primers will fall into the heavy-bodied category.  You will have better luck at a paint store.  Also, do not add any tint to this primer.  It can help with color clarity, but in this case you want the least amount of pigment in the primer possible.

As you prime, pay attention to your equipment.  If there is still a fair amount of chalk, you will tend to pull some off into your roller as you paint.  If you notice the consistency of your primer getting a bit thicker as you go, stop and wash it out.  You will waste primer, but it will minimize the amount of the chalk that you are putting back on the wall.

Wait a bit longer than the instructions dictate before you try to do anything after you prime.  I would give it at least two days before you touch it to give the primer the best chance to cure.  After a couple of days, do the tape test and see how it looks.  If it is good, go ahead with your finish coat.  If it pulls off, take the chip to the store where you bought the primer.  This is another good reason to find a good paint store.  The store can send the chip to the manufacturer for an analysis, which will identify what the material is that is chalking and give you another clue toward solving the problem.

Answer 2

I'd just try a damp soapy sponge and dry it when you're done. It'll be easier to clean up if the wall has glossy paint.