Concrete Densifier for extreme dusting floor?

[charbar]

Ok guys, I have a 20x40 ft patch of concrete on the far end of my shop that Ive been unhappy with since day one. It was an afterthought to pour that section and I believe it just got dry on us to fast. Surface is fairly rough (for a shop floor), not super hard by any means (in comparison to the rest of the shop) and it dust TERRIBLE.

It was poured around 3-4 years ago. Im sure the best option is to tear it out and repour, but Ive made up every excuse I can to not have to do that.

Ive considered many different solutions but Im not so sure any of them will work very well. HOWEVER I just found out about something called concrete densifier. Anyone have experience with this?

Is it something I can put over 3-4 year old concrete to help with surface hardness as well as control the dusting? I hate sweeping that area because its just a giant cloud of concrete dust in the shop by the time Im done and a dustpan full of dust I swept up.

I guess my question is, is it something that will work "good enough" or would it just be a waste of money? That area doesnt see an extreme amount of foot travel.

Im definitely not a concrete expert, so any insight would be greatly appreciated.

Thanks!

Edit to add:
Will densifier somewhat 'fill in' some of the low spots (between aggregate, not talking big areas that hold loads of water), or will it saturate completely and leave the same finish texture? If so, can something else be poured over the top then to somewhat level/smooth out the floors finish?

 

[CombatNinja]

Might work, might not. You only have a little bit of money to risk in the bargain. Densifiers absolutely help to reduce dusting but I think there are limits. Once you are into the realm of "chalky", it might be too far gone.

As to the second question, no densifier is going to "fill in" anything. It works by virtue of the fact that it soaks completely into the substrate. You could do a seal coat along with the densifier but you have to have realistic expectations as to how much thickness you are going to get with that. Maybe a clear polyurea would be better as you can get some thickness built up with that. Never worked with those products before so I'm sure an expert can chime in.

 

[Shea]

Densifiers are non film forming. They penetrate the subsurface. There is also an inverse relationship in terms of how well they work on concrete. The better the surface is, the better the densifier works. The worse shape it is in, the less effective they become. Densifiers rarely do much with concrete that dusts as badly as you describe.

Your best bet would be a light grind to remove some of the thin layer of weak concrete and then apply two thin coats of a solvent-based acrylic sealer. It is a relatively inexpensive film forming sealer that will work much better at keeping the dust down.

 

[LegacyIndustrial]

Shea nailed it. Grind that area and seal.


Sent from my iPhone using Garage Journal

 

[charbar]

How much can a guy realistically expect to grind off? 1/8"? 1/4"? More? Never been around a concrete grinder before.

Im sure at 1/4 inch it could be ground completely flat and get rid of all the weaker stuff on top, maybe that isnt doable though. 1/8 inch would leave a little roughness, but it sounds like acrylic sealer may take care of those for the most part? 1/8" may leave some of the weaker surface though.

Or is it more "grind until your hearts content" type of deal?

Id have to rent a grinder. Anything in particular I should look for in a rental? What about grinding around an open staircase? Get as close as you can with a walk behind and then just go to town with a handheld one basically?

Thanks

 

[Armorpoxy]

Shea 100% correct. An inexpensive sealer will work wonders. We carry these as do other vendors who participate on GJ.

 

[Shea]

How much can a guy realistically expect to grind off? 1/8"? 1/4"? More? Never been around a concrete grinder before.

Im sure at 1/4 inch it could be ground completely flat and get rid of all the weaker stuff on top, maybe that isnt doable though. 1/8 inch would leave a little roughness, but it sounds like acrylic sealer may take care of those for the most part? 1/8" may leave some of the weaker surface though.

Or is it more "grind until your hearts content" type of deal?

Id have to rent a grinder. Anything in particular I should look for in a rental? What about grinding around an open staircase? Get as close as you can with a walk behind and then just go to town with a handheld one basically?

Thanks

The goal with the grinding is to remove a very thin layer of the excess laitance that is on the surface. This will allow the acrylic sealer to adhere better and not just attach itself to a real dusty surface. You can rent a floor maintainer and Diamabrush attachment from your local Home Depot. You really don't need anything more aggressive than that for an acrylic sealer. We have an article that discusses the process here. https://allgaragefloors.com/how-to-grind-garage-floor/

Again, the goal is a light grind - not layers of concrete removal.

 

[Armorpoxy]

Shea is 100% correct.

Attempting to grind 1/8 or 1/4" is like a mile...its MUCH more work than can be anticipated, and to grind that much material (and aggregate) you need a very heavy duty grinder with aggressive diamond tooling.

A light scratching up for absorption and adhesion is all that is needed. Attempting to level a floor by grinding is almost impossible since as you grind it's difficult to hold the benchmark tolerances.

 

[charbar]

Awesome, thank you so much for the guidance you guys. I'm sure Ill have more questions along the way but this has definitely got me headed the right direction.

Major help