Control joint filling questions

[biggziff]

It's unlikely I'll ever Epoxy my floor, but I do want to fill the joints with something. I've been reading about Urea, Sikaflex and its similar products and epoxy/filler like Legacy's Xtreme Set. Question is...isn't using something like Xtreme Set defeating the purpose of the control joints to some degree? If it's so strong and will bond the 2 sides of the slab, isn't it likely to crack and potentially crack the slab edges when the slab pieces move?

If so, isn't something like Sikaflex a better choice due to its flexibility?

I'm trying to fill and level the crack so parts don't fall into them and my rolling tools and chairs don't get hung up in the cracks.

Thanks

 

[Garage Flooring]

It's unlikely I'll ever Epoxy my floor, but I do want to fill the joints with something. I've been reading about Urea, Sikaflex and its similar products and epoxy/filler like Legacy's Xtreme Set. Question is...isn't using something like Xtreme Set defeating the purpose of the control joints to some degree? If it's so strong and will bond the two sides of the slab, isn't it likely to crack and potentially crack the slab edges when the slab pieces move?

If so, isn't something like Sikaflex a better choice due to its flexibility?

I'm trying to fill and level the crack, so parts don't fall into them and my rolling tools and chairs don't get hung up in the cracks.

Thanks

Scotty can talk better about his own products than I. I will speak more in the general spirit of your question. We sell a similar product called TL829, which is a 100% solids expansion joint filler.

1. You are correct that you certainly will not have as much flexibility with a joint filler than you would have without. Flexibility is not the right word here but helps to visualize. The fillers are, in fact, flexible, so they allow movement.

2. Sikaflex and others are basically high-end purpose drivel caulks. They are great for filling joints if you are not going to coat or if you are using a sealer. I would not put an expensive coating system over Sikaflex. It has more give than our joint filler if a joint filler gives more than the coating on top of it you can have an issue.

3. To me, this says it all I'm trying to fill and level the crack so parts don't fall into them and my rolling tools and chairs don't get hung up in the cracks. If that is what I was doing and I was not coating the floor Sikaflex would be a better option IMHO than our joint filler

 

[biggziff]

Scotty can talk better about his own products than I. I will speak more in the general spirit of your question. We sell a similar product called TL829 which is a 100% solids expansion joint filler.

1. You are correct that you certainly will not have as much flexability with a joint filler than you would have without. Flexability is not the right word here, but helps to visualize. The fillers are in fact flexible so they allow movement.

2. Sikaflex and others are basically high end purpose drivel caulks. They are great for filling joints if you are not going to coat or if you are using a sealer. I would not put an expensive coating system over Sikaflex. It definitely has more give than our joint filler. If a joint filler gives more than the coating on top of it you can have an issue.

3. To me this says it all I'm trying to fill and level the crack so parts don't fall into them and my rolling tools and chairs don't get hung up in the cracks. If that is what I was doing and I was not coating the floor Sikaflex would be a better opton IMHO than our joint filler

Thanks for the reply. I have sealed the floor with StampShield previously (post cure) so really just looking for a way to get rid of the joints.

Appreciate you taking the time to respond.

 

[Garage Flooring]

Thanks for the reply. I have sealed the floor with StampShield previously (post cure) so really just looking for a way to get rid of the joints.

Appreciate you taking the time to respond.

Go get some Sikaflex... maybe some backer rod depending on the depth and call it a day

 

[gtae07]

I used the gray Sikaflex to fill mine. It keeps bug carcasses and dust and fasteners from collecting in the joints.

 

[LegacyIndustrial]

Sawcut joints are there for the initial crack. They are suggestions to the slab that it should crack on those cuts. The slab does not always listen. Once cracked you are cleared for take-off. Can they crack again? Anything is possible.

Perimeter joints can be filled with Dap's Concrete Repair Sealant, they don't see traffic.

 

[DynoDave]

I used Sikaflex on the saw cut control joints in my approach after it cracked. Sand to fill the cracks, Sikaflex on top. Been 3 or 4 years, and it still looks good.

 

[Tpsykes]

Rapid set self leveling sealant is sold at home depot is very good as well. Rapid set has much better customer service than sika if the need arises.

 

[biggziff]

I used Sikaflex on the saw cut control joints in my approach after it cracked. Sand to fill the cracks, Sikaflex on top. Been 3 or 4 years, and it still looks good.

Thanks. I'm probably going to use closed cell backer rod, but sand sure sounds easier!

 

[Zippercat]

If your joint cracks are deep and uneven, the backer rod may not be the best option because the Sikaflex will run around it. It is very fluid out of the tube and you can empty a tube very quickly trying to fill a deep crack. I've used fine sand to fill joint cracks to about 1/2 to 3/4 inch from surface, then Sikaflex.

 

[biggziff]

If your joint cracks are deep and uneven, the backer rod may not be the best option because the Sikaflex will run around it. It is very fluid out of the tube and you can empty a tube very quickly trying to fill a deep crack. I've used fine sand to fill joint cracks to about 1/2 to 3/4 inch from surface, then Sikaflex.

Thanks for that. These are both deep and uneven. I'll grab some sand from a box store to try.

 

[biggziff]

Ended up using closed cell backer. Was ridiculously easy. I left the Sika a bit proud of the joints and will go back with a razor scraper to level it all off once it's cured.

I also over-bought on the sealant. Ordered a case....used 3 tubes.

 

[woodee]

Ended up using closed cell backer. Was ridiculously easy. I left the Sika a bit proud of the joints and will go back with a razor scraper to level it all off once it's cured.

I also over-bought on the sealant. Ordered a case....used 3 tubes.

You can use the rest to fill driveway/patio/sidewalk joints as a preventative measure.

 

[biggziff]

You can use the rest to fill driveway/patio/sidewalk joints as a preventative measure.

Right. I have plans for another couple tubes, but after that I'll have to see if I can sell the rest! No worries...

 

[maplepuck]

great tips, nice thread...have this on my to-do list as well...love this forum

 

[steiner5]

I was planning on using Silkaflex on my saw cut control joints but am now wondering if I should do this before or after I epoxy paint the floor. I wanted to fill the joints first and then paint the floors with epoxy as it would give a nice uniform look. Is there any issue with epoxy sticking to the Silkaflex?

Thanks....

 

[Armorpoxy]

We always recommend filling the joints after you epoxy, the reason for this is that if you coat over the joint filler, then if/when the slabs move you will develop cracks since the epoxy is not flexible.

 

[pvfjr]

Anyone want to keep talking about filling their cracks?
I have hand-troweled control joints in my slab, so they're more generously sized than saw-cut. I filled a couple of them with sand leaving 1/2" in depth for some of the Rapidset self leveling hybrid silane polyether. It self leveled pretty well. It's tricky getting to where you feel like it's the "right amount".

The trouble is, it's a bit squishy. It's been over a week in temps in the 40s-50s. I'm concerned casters will still sink in and "feel" the cracks as I roll by with the trans jack or something.
Should I switch too a polyurethane self-leveling concrete sealant? I watched the Michael Builds video on the topic on YouTube. The Rapidset adhesion and flexibility is shown to be impressive. Polyurethane is referred to as "old tech", and is shown shrunken and worthless in the old driveway cracks. Would this matter indoors though? Has anyone used a polyurethane long-term indoors with favorable results? Would it be stiffer than the Rapidset?

 

[pvfjr]

I did some more digging. It looks like the Sikaflex 1C SL is a polyurethane base. They list a Shore A hardness of 45 +/- 5 tested to ASTM D2240 standards.

The Rapid Set silane polyether is tested to a Shore A hardness of 15, tested to ASTM C661 standards. From what I can tell, C661 just has more specs for how the sample is prepared, but should be basically the same test. The polyurethane probably predates the C661 test, so they just used the D2240 test for general rubbers instead.

All that to say, I'll try a tube of Sikaflex on the next few joints and see how I like it. I'm sure the Rapidset is better for an actual long-term outdoor sealant, but I just need a stiffer joint filler in my case, and it will be protected from the elements.