Epoxy - Joint Question

[northbrook]

After months of comparing garage flooring Im 90% sold on Epoxy and using Epoxy Coat but cleaning my floor this weekend I spot this fiber like material that goes from one end of my garage to the other. I thought it was cement but it feels porous and like fiber board material

1. Does anyone know what this is? So I can call it by name.
2. How have other dealt with it? Im thinking Id have to grind it down and paint around it, which would be a weak spot in the flooring and exposed to pealing.

If Im going to spend a lot of time preparing the floor and not sure if its worth all the time if this fiber material is not going to hold on to it and expose the floor. Thanks in advance for you advice. If this seems like a deal breaker my second option is something like race deck, simple but 2.5X cost

 

[LegacyIndustrial]

Looks like fiberboard. Used when creating joints in exterior concrete.

 

[northbrook]

Thanks scotty, is this typical for the installer to use fiber board, I assume its used to help with expansion and contraction? Do you have a ny recommendation or experience preparing a floor with it on? Anyone?

 

[Edger]

Fiber board expansion joint material is a pain in the A$$ for coating over. It is very difficult to cut down with anything to allow you to put a flexible joint filler on top. Epoxy will stick to it without problems, but it does not look finished. Can't offer any suggestions.

 

[Flooring For Garage]

It's a pain in the ****, but you may be able to trim away the exposed fiber just enough so it doesn't look like an unfinished edge... I was able to do this a couple of times, trimming enough so that it isn't an eyesore. It's not easy work though... ugh!