Polyurea and Expansion Joints

[Metallitubby]

I am ready to apply polyurea to my fairly new'sh concrete slab, and then it hit me. What product am I supposed to use for the expansion joints that works with polyurea?

Any info is appreciated.

 

[dirtydrew420]

I can tell you NOT to use any sika product

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[GRivera]

I thought most used Sika Flex? what is the issue?

 

[dirtydrew420]

I used it and the ******* joint turned yellow, not a huge deal because it's a work space but it was a little upsetting to see.

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[Shea]

SikaFlex, as well as other flexible self-leveling polyurethane joint sealers should not be used. They are "sealers" and not intended to have coatings applied over them. Another issue is that due to the amount of flex, if a heavy object is rolled over a joint it can actually cause the coating to crack, especially epoxy coatings.

If it's desired to fill contraction joints, it should be done with a polyurea or epoxy joint filler that has just enough flex that if the joint continues to crack down the middle, it will not telegraph that crack up through material and into the coating. This article here gives examples and explains the differences.
https://allgaragefloors.com/can-i-fill-my-contraction-joints/

 

[LegacyIndustrial]

XtremeSet100 for filling prior to coating. Otherwise an SL sealant like Sika.
https://www.legacyindustrial.net/pr...atings/xtreme-set-100-crack-joint-filler.html

 

[Metallitubby]

Thank you for the responses. I think you've answered my question. The *need* to fill in the saw-cut joints is more for visual appeal (and maybe less cleaning) than anything else. I might just leave them be for now.

*Edit - I think I will just use the Sika Pro after I've coated my floor. It's a hobbyist auto shop after all, not an art gallery.

 

[b-boy]

I just left mine as-is. They look perfectly fine. I don't think it detracts from the floor at all IMHO.

 

[Armorpoxy]

We normally recommend just leaving them be for the above reasons.

If you want to fill them a company named Metzger and Mcquire makes polyurea caulk called RS-88 in 100 colors to match virtually any floor.

https://metzgermcguire.com/products/polyureas-2/spal-pro-rs-88/


We offer Flexible Joint Filler but only in medium gray color.

 

[Metallitubby]

I just left mine as-is. They look perfectly fine. I don't think it detracts from the floor at all IMHO.

Do you have any issues with small debris/dirt getting trapped in them? This is probably my only and/or biggest gripe with not filling them with some sort of caulk-esque product.

 

[bmwpowere36m3]

I filled the joints with Sika SL after applying polyurea over a month ago.

 

[Metallitubby]

I filled the joints with Sika SL after applying polyurea over a month ago.

This is where I was heading after the initial responses. Would you happen to have any pictures?

 

[GRivera]

We normally recommend just leaving them be for the above reasons.

If you want to fill them a company named Metzger and Mcquire makes polyurea caulk called RS-88 in 100 colors to match virtually any floor.

https://metzgermcguire.com/products/polyureas-2/spal-pro-rs-88/


We offer Flexible Joint Filler but only in medium gray color.

Is the RS-88 application for after Polyurea is cured?

 

[Armorpoxy]

Hi, normally the caulk is done after since if you coat over caulk and the slabs move you will get cracks in your epoxy.

Note that RS-88 is a Polyurea caulk and remains flexible so it won't crack if the slabs move. We refer to this product when people want to fill their cracks with something other than standard gray color since the RS-88 comes in 100 colors. It's a two part product that comes in 'twin' caulk tubes and uses a mixing nozzle that affixes to the tubes.