Expansion joint help please

[Jc737]

I’m in the process of prepping my garage for coating and the previous owners filled the expansion joints with some type of cement/patch product.

There are areas where it was loose and I picked it out. There are also areas that feel solid. So should I remove all the old material? The areas that feel solid have shrunk so it’s not quite flush with the slab. It’s a 20 year old slab.

Or would filling in the joint where I removed the old loose material and laying over the top of the existing to make it flush work?

 

[Kaizen]

some more info will help get better answers. how do you plan to prep the floor and what floor are you putting down?
i used silkaflex on mine and then epoxy over it. it needs to have enough to bite into so it doesnt work its way out. How deep are the ones that have shrunk?
what they have and what you will do is cosmetic. So really depends on your end goal.
If it were me and had time i'd take a cold chisel and knock as much out as i could. if you havent cleaned yet nor prepped you can use an angle grinder with a diamond wheel but that makes a hell of a mess. I'd shoot for half inch deep and the silkaflex flow so its just below the surface.

 

[Jc737]

It’s been shot blasted and has some areas of pitting so will probably have to go the epoxy route and I don’t expect it to cover up the pitted areas. I will use one of the vendors supplies to try and fill in the pitted areas to improve my result.

I wanted polyurea but I think that will just enhance the damaged areas as suggested before.

The areas where the previous filler shrunk is only about 1/4” at the deepest spots. Majority is more like 1/8” and where I picked out the loose filler it’s about 1/2”-5/8”.

Thank you for your response. My first coating job so this will be interesting to see the results once completed.

 

[Kaizen]

Sounds like shallow cuts. Should have been about 1/3 of slab thickness. Think I’d put the sealant in and call it a day. As long as it seems stable it should be fine. Tape both sides before applying as it ***** to scrape off. Remove tape after it finishes flowing. The warmer the better so it can self level.
I did my epoxy as well. Lay it out and measure exactly. Only place I screwed up was my sprinkles. Just did not get the look I was after.


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