Hi Andrew. It sounds much worse than what you were initially describing. Heavy dusting of the concrete is one thing. However, if the shape of the concrete is bad enough that it tends to crumble or scrape away easily, then a densifier is not going to help at all. Neither will an acrylic coating. You will just be throwing good money after bad. It will just peel right off sometime after it dries with a thick layer of concrete dust attached. You might be at the point where heavy grinding needs to be introduced and a polymer-modified concrete patch applied. We would recommend calling in a concrete expert to evaluate the condition of the walls before you do anything else.

Thanks. i dont know if its considered “stem wall” as I didnt know that term before and cant put photo here. basically its like 6 inches or so high around the 3 sides of the garage floor, 2 sides being house room sides and the other an outside wall, all 3 getting rather well deteriorated, forget about passing any screwdriver test, it crumbled chunks off.

But i will look into what you say. i see via google different ones penetrate less or more, like 1″ vs 4 inches. the one you show says 2 inches. maybe thats enough. but i dont need so much of it? ? i see a quart for a lot less money of one that says penetrates 4 inches but its not lithium based but the write-up sounds good. named Concrete Sealer X-1 $21.

i dont want to try to put a complicated job into it, grinding, or to wear away much more into the surface especially under a wall. i was hoping to be able to just clean it up some and coat a densifier on and improve it enough? what do you think of this product that says it penetrates further, but maybe that means pour more on and this would be a sideways application under a wall in some places.

Hello Andrew. Deterioration of the stem walls as you describe is generally an indicator of the outside wall being wet. Before you apply an acrylic coating, we first recommend cleaning and scrubbing the surface first with a very short bristled deck brush to remove loose material and residual dust. Let it dry for a day then apply a concrete densifier. We have an article here describing what it is and how it works. Give it a week to react and then you can apply an acrylic sealer if you like. It will slow the dusting down, but how well it works will depend on how bad the shape of the concrete is and how much moisture gets through.

Ahh… OK, then. It will work fine for that.

Thanks for the reply Shea. It’s a basement floor, so foot traffic only, but one section of the basement will be finished off and vinyl flooring will be installed once sealer is applied & dried off.