Is It OK To Fill Expansion Joints?

[bikerneil]

I will soon be finishing my garage floor with Polyurea and I want my finished floor to have a really dramatic and finished look. I am planning to fill my expansion joints prior to doing the work. My house is 17 years old and the garage floor shows absolutely no signs of settling or cracking.

Is it ok to fill these expansion joints, or do these joints still play a role in keeping the floor from cracking? My floor is a Post Tension Slab design in Southern CA.

One other question - is there a preferred order to doing the filling of these joints? I have heard some people say it is best to:
1. Grind the entire floor.
2. Fill the joints.
3. Hand grind to smooth the repair areas.
4. Paint floor with Polyurea.

Others say it is best to follow this process:
1. Fill the joints.
2. Grind entire floor.
3. Paint floor with Polyurea.

Thanks.

 

[Retroman]

I filled my tool joints in my post tension garage with Resiweld 1000 and silica sand. Has been done since October 2018 and no issues. Its not a concern its just to allow the concrete to crack there and not look bad. If you clean your joint you can probably see a small crack running the length of it. I am in the concrete cutting business and cut these joints daily. Most if not all of the big warehouses fill the saw joints in the speed bays so the hard wheeled lifts don't spall those joints. So that is good enough for me.

I see your in Carlsbad, just helped my daughter and SIL move back to Vegas from Vista yesterday.

 

[Retroman]

I filled mine then had a epoxy guy I know grind and epoxy the floor. The Resiweld will not match your concrete. I will try to find and post some pics.

 

[Retroman]

Here is the floor after joints filled ground and primed.

 

[pima67]

As an aside, I still wonder why they troweled in joints in my garage which is part of the post tensioned slab. Once tensioned the concrete isn't going anywhere. Of course no joints in the house part of the slab. I did have a small crack where the garage "steps" on two sides meet at the house entrance door. I filled it in with thin set I had on hand and waited a while before applying epoxy. Impossible to tell where the crack was some 10 years hence.

 

[bikerneil]

Thank you Retroman and pima67.

 

[LegacyIndustrial]

Here is an alternative, available in colors (good for clear/sealer coatings). A couple of videos to watch as well.

https://www.legacyindustrial.net/pr...atings/xtreme-set-100-crack-joint-filler.html

 

[rjacobs]

Ive had 2 houses with post tension slabs and neither have had any expansion joints cut or trowled into anywhere. But the first was only built 6 years ago and the current was just built so maybe post tension technology is getting better, I dont know.