Paint limestone basement

[Petertaylor]

Our 110-year-old house has a basement of limestone wall. It is solid and the mortar still pretty good.  But it has fuzzy effervescence in places, and so much sand drops off that we need to vacuum every other week. It is a good-looking wall, and the wife does not want it replastered with new mortar.  

So the plan is to brush and vacuum the wall, then paint it with clear latex paint.  The hope is that by using latex, the wall will still breath (not trap moisture), and the dropping of sand will be greatly reduced.

Any ideas or experience?  Thanks in advance for your comments.  —Peter

[Admiral]

I can't speak for limestone, but I had a cinder block wall with the same effervescence issue, at first painted with latex, and that failed in relatively short order and the problem re-occurred.  I then went with Drylok original formula, two coats, and in the following two years it has performed very, very well with no signs of any seepage or failure.  That's all I got, hope it helps.

https://www.homedepot.com/p/DRYLOK-Origi.../100118662

[adamcherubini]

I’m not familiar with breathable latex, or how that would even change anything.

The solution is a perimeter drain and exterior waterproofing. Failing that, consider lime wash paint.

Also, check your grading and guttering.

[Snipe Hunter]

I’m  not familiar with breathable latex, or how that would even change anything. Flat and eggshell latex is porous.

The solution is a perimeter drain and exterior waterproofing. Failing that, consider lime wash paint.

Also, check your grading and guttering.

[Woodenfish]

I believe that the limestone may need to be primed before painting with latex because of the pH.

[Snipe Hunter]

Any way you can parge the walls (type S Mortar) and paint the parge? Parge holds paint well. If the walls are damp, the paint will be damp too and may not bond. Latex is breathable to an extent. The reason people use Drylock is because it sticks well and is non porous. The only dampness on the walls will be condensation which is to be expected in a basement unless it's a conditioned space. .

[Cabinet Monkey]

FIRST thing would be is to check your home’s water management - or lack of.  Gotta figure out how to get the water away from your foundation or your fighting a losing battle that no paint is gonna fix.

[Petertaylor]

Thank you all for the replies and suggestions. The original question was not about waterproofing the limestone walls, but minimizing the sand that drops off. I just sprayed on a coat of clear latex. We’ll see what happens. Time will tell. -Peter

[Cabinet Monkey]

Thank you all for the replies and suggestions.  The original question was not about waterproofing the limestone walls, but minimizing the sand that drops off.  I just sprayed on a coat of clear latex.  We’ll see what happens.  Time will tell.  -Peter

I think you missed the most import point in thiis thread.................the moisture.

The Efflorescence you're having to vacuum up is because water is passing through your wall carrying disolved salt with it. Until you divert that water from entering your wall, your problem will continue. It'll be interesting to see how long your latex lasts before it fails.