concrete gap seal

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Old 09-27-19, 03:22 AM
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concrete gap seal

I need to fill a gap, about 1/2" wide between the garage floor and the approach apron. The stuff I used the last time worked well, held up for a long time, still had a bit of elasticity, and required a chisel to break it away from the edges so the bond was good. But it looks like the apron settled just a slight bit, cracking down the middle, so time to replace. Problem now though is that it lasted a long time, I'm thinking around 15 years or more, and darned if I can remember what I used. So I'm looking at two options, both that I think should be quality products, and wondering if anyone has any preference or whatever for either Quikrete concrete gap filler of Sikaflex gap filler.
 
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Old 09-27-19, 03:39 AM
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How deep is the crack? If more than 1" deep use a backer rod. Leave about 3/4 to 1/2 inch depth then use the crack filler. Not familiar with the Sikaflex. I have used Quikrete products. They're OK. A lot depends on how it's applied and the weather conditions. Will it last 15 years? Not likely.
 
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Old 09-27-19, 04:13 AM
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Thanks Norm. Yeah, it's close to the right depth from when I did it before, but has settled some in a few spots so I figured on vacuuming out the few locust leaves that I imagine have already gotten in there this week, use a flat bar to level off the sand, then backer rod to bring it up to a relatively consistent 1/2" or less all the way across. Had thought I might get to it tomorrow, but weather doesn't sound the best for this weekend now, and they're saying summer will be back next week so may hold off and do it then. As far as lasting 15 years, like I said, that's only a guess, and it may very well be that it's been split for 5 years and I'm just now getting around to making it a priority!
 
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Old 09-27-19, 04:58 AM
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I used a Sikaflex product once that came in a quart bottle that was self leveling and you just poured it in. Not impressed with it. It would develop a crack right down the middle due to movement. But I have had good results with the Sikaflex caulking tubes. Also with Loctite S10 and S20.

2 factors to make sure it lasts a long time- having the joint clean, and using backer rod. Grind the edges, blow them out, brush them, blow them out again. If using a non-self leveling product, tooling is a good idea, to force the product into the pores on either side... it promotes good adhesion. And a little silica sand is always nice to sprinkle lightly over the top.
 
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Old 09-27-19, 05:13 AM
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Ive got my entire driveway sealed with the Sikaflex self leveling sealer, I get maybe 3 years and then due to minor settling/heaving I have to replace.

My drive was not installed correctly, not proper base for drainage so I have to keep it sealed up or get massive heaves in the winter.

I find it works best when there is only about 1/2" thickness so I use sand to fill the gaps before applying.

I have used other brands, even some from local concrete supplier, all performed the same!
 
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Old 09-27-19, 08:49 AM
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Thanks guys. Yes, it is the Sikaflex caulk I was thinking of, not the pourable. So I guess Iíll see which one I end up deciding on. I thought about using sand as you mentioned Marq, and I do have plenty of clean sand, but wondered if the sand might tend to draw moisture out of whichever product I use, and possibly affect the curing process, so decided to use backer rod on top of the sand.
 
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Old 09-27-19, 11:00 AM
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the sand might tend to draw moisture out of whichever product I use

No, the sealer is not water based and the sand is just cheap filler vs backer rod,

Backer rod works, but if it doesn't seal then all your sealer drains away, with the sand it's obvious that it's filled!
 
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Old 09-27-19, 11:13 AM
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I'd use backer rod if using a caulk type filler. I would think caulking against sand would be difficult.
 
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Old 09-27-19, 12:17 PM
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I've used sand to fill. It works but backer rod is better because it always stretches, allowing some up and down movement without breaking the bond. The whole idea of backer rod is so that the sealant is only firmly attached to the two surfaces on either side of the gap, with a cushion underneath. So if you use sand and the sand is wet and frozen, the caulk won't be able to flex. If either side heaves unevenly (one side heaves while the other doesnt), that frozen sand will break the bond on one side or the other. Let's say that 9 months out of the year sand is fine. Backer rod is better if it fits.

Sand is useful when working with runny self levelling products, if you need to create a dam.
 
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Old 09-28-19, 06:43 AM
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The self leveling flow of Sikaflex is great for gaps and crack between asphalt and Belgium blocks. I have 200 feet of blocks and that develop gaps from ice over winter.

https://www.homedepot.com/p/Sikaflex...093828%7D%3Aqu

Sikaflex flows into cracks and before hardening use small paint brush to smooth out. Next day paint with driveway sealer.

In past had mixed play or beach sand in driveway sealer to fill cracks but it is not adhesive or flexible and cracks reopened.
 

Last edited by doughess; 09-28-19 at 07:35 AM.
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Old 09-28-19, 07:25 AM
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use small paint brush to smooth out

If it's self leveling you dont need to do anything after installing!
 
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Old 09-28-19, 08:13 PM
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Marq1: If it's self leveling you dont need to do anything after installing!
If more than enough to fill a crack/gap is dispensed the excess is on the surface. It is a thick liquid and does not flow out like water.

The brush is used to flatten it out and blend it in rather than leave drip like bumps on the surface.

Like various other man made things it is not perfect. Found it was better, an improvement over other products.

I try to find better ways, rather the find fault.
 
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Old 09-28-19, 11:23 PM
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The brush is used to flatten it out and blend it in rather than leave drip like bumps on the surface.
Not wanting to beat a dead horse, then you are using something other than self leveling material.

Self leveling flows out like thick syrup, it flattens out instantly and does not requiring any post work.

https://www.google.com/search?newwin...i4sQW87aLYDA29

They do make other materials for gaps on slight inclines that is more caulk like if that is what your referring too!
 
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Old 10-03-19, 02:25 PM
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Regardless of marketeer's text “self-sealing sealant”, found Sikaflex to be the best product I have used to fill gaps that develop between asphalt and Belgium block curbs.

Sikaflex Self-Leveling Sealant is a single component, self-leveling, premium-grade polyurethane sealant with an accelerated curing capacity used to seal gaps, joints and cracks. No tooling feature saves time and money.
Am not a hyper critical perfectionist who feels victimized by vendor for having to use $1 paint brush to tweak job.

Hope Sikaflex sealed areas will hold up better in freeze and thaw cycles than prior products.
 
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