Do you fill cracks in the control joints before sealing/coating floor?

[wantonsoup]

As detailed in another thread, I had my floor coated with a polyurea/polyaspartic coating. The company advertised how important it was to fill every crack before starting with a flexible material. They also offer caulking in the control joints completely to create a smooth floor. I heard and read not to do the latter as you'll take away the good natural place you want the concrete to crack.

So my question is - is it normal or not to do any filling of the cracks within the control joints, if you're not going to fill the joints in? Or do you just leave them alone, vacuum out any loose material and coat on top of the crack with no other prep on them?

Thanks.

 

[Shea]

Generally you leave the joints alone, cracks and all (other than proper cleaning of course). When you epoxy over the joint there will always be a little excess that tends to collect at the bottom of the joint. Many times this will coat over small cracks anyway, larger ones in the joint you will still be able to see if you look for them.

The only time you would fill a crack in a control joint is if it is a rather large crack that may be close to the width of the joint itself.

 

[Zmw]

Shea, I am about to work on my parents garage and put down an epoxy floor. But, the floor is from 1970 with NO control joints. 3 car garage, maybe 700 sq ft +/-. There are 1-2 long cracks that run the course of the floor.

How do I handle - literally no control joints. Should I caulk the cracks with sikaflex and epoxy over?

As I get closer to my project I will post pics of the floor, but any advice is appreciated. Thanks!

 

[LegacyIndustrial]

In lieu of a crack chasing blade mounted to a grinder, tap the crack with a ball-peen hammer or chase with a masonry chisel to break off any weak edges. If you have the crack chaser, that is the preferred method.

Vac out any loose debris.

Fill crack liberally with an epoxy based gel crack filler. Allow to cure and grind flush.

Here is a link to out offering, there are others available in the marketplace.
Link: http://legacyindustrial.net/cart/hd821-crack-sealant-gel-style-p-94.html




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[pauls_workshop]

We got two different questions going on this thread. ZMW, on yours, I would fill those cracks with epoxy before doing the main basecoat on the floor. I had some cracks like this in my basement in the middle. My basement has expansion joints all around the perimeter but nothing in the middle. On the perimeter, I used sikaflex sl after the epoxy, but I filled in the hairline cracks in the middle. First chase them with a dremel or similar method, then fill in overfilled, then grind flat, then ready for basecoat. Do two coats if you have to to make flat. - Paul

 

[wantonsoup]

... a crack chasing blade mounted to a grinder ...

Is it standard to clean up cracks a bit that are located in control joints, before coating a floor?

 

[pauls_workshop]

Wanton, by the way I have to admit I prefer "lemongrass" but your name is ok I guess.

Anyhow, what Shea was saying was you don't worry about cracks inside of a control or expansion joint. The best thing to do is just do your epoxy floor, then go back after and fill in those control or expansion joints with sikaflex sl and be done. There are flexible products Legacy Scotty above sells that you can fill in if you want, then epoxy over that filled in joint instead. You could get a crack later on there though if you do that, so I don't recommend that. It depends on your particular floor and situation whether they might crack then or not later. To be safe, I would just fill *after* epoxy with sikaflex sl and not worry about it ever again.

What ZMW was talking about was a crack somewhere where this isn't a control joint. Those I would in fact fill in with epoxy, but I just used 100% solids epoxy to do that like the floor basecoat above it. They could crack again there too. It's a bit of a risk there, but that is what I did and recommended to ZMW.

Merry Christmas and Happy New Year! - Paul

 

[LegacyIndustrial]

Crack probability/volatility increases in unheated spaces found where temps dip below freezing.

Merry Christmas GJ!!




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[Bordeauxman]

Two questions:

1) What are the benefits of POLYUREA cement coatings?

2) I plan on installing a lift in my garage when built. Is there any reason NOT to coat to cement slab before the lift installation?

Thank you in advance.

Jeremy

 

[Shea]

Hello Jeremy, here is an article on polyurea/polyaspartic coatings that will help explain the benefits and how they work.

As far as the lift goes, it depends on what kind you are installing. If you are just drilling holes to anchor the lift, then coating before hand is fine.