Slab grinding, when is enough, enough

[slackdaddy1]

Grinding a 600 sq ft power troweled slab.
using the HD diamabrush on floor machine.
about 2/3 of the surface opened right up into a white porous texture, the other 1/3 remains somewhat "shiny" with just scratches.
Is this typical? it does absorb water,
Do the shiny areas need to be ground more ?? I am not sure they will ever look like the white porous areas.

 

[tncatadjuster]

You can't level a slab with that tool, so you have what you have. I have installed coatings on slabs like that with success if in fact the other areas are sanded, and all other conditions are right.

I'm sure you will get advice from the manufacture of the coating.

Good photos.

 

[LegacyIndustrial]

The key element is the floor being porous. Go over any shiny spots with a hand grinder if you have to.

When water is tossed on the slab it should turn it dark be absorbed readily.

Want to add that power troweled slabs are tough. I recommend a real diamond grinder for these like the EDCO TL-9 or similar.

 

[Armorpoxy]

The shiny areas sound like they need more work. Scotty is correct, if the water doesn't easily absorb, then you could have adhesion issues w/ the epoxy.

 

[slackdaddy1]

Put 60# of weight on the machine and spent another 6 hours, It got a lot of it, but not all. I have a lot of small 10-20 sq inch areas.
picked up a 3.5 diamabrush for the grinder. it is labeled as the "floor coating remover" version, but it is all they had. tried it out, it makes quick work of the remaining shiny areas. guess I'll be spending a couple hours on my knees.

Nick

 

[Dick in Wisconsin]

I did the same thing you're doing before applying Rust Bullet to my new shop floor.

When I was done grinding, I think my floor looked much like yours. Most of it was "opened up" ... with a few shiny spots. I put the Rust Bullet on it and all is well a few years later. Have no idea where the shiny spots were.

If you're so moved and your body can handle it ... grind away.