garage floor crack ?

[cvcman]

Ok I posted this before with not much outcome. I have a crack across my gargae floor ( 16ft) its about 1/8" wide. I would like to fill it but wondered IF I do it with Sackreet crack filler will it just crack someplace else ??

Also IF I do the epoxy paint floor and I use my floor jack etc wont this dig the floor up ??

I have some flex concrete caulk but its lighter color than than the floor so may look worse than the crack.

They never cut the floor when installed 18 yrs ago

 

[A_Pmech]

When I built my shop I poured the floor in sections with highway expansion joint material between the sections. To fill in the 1" wide depressions where the expansion joints were installed I used Hydraulic Cement. It is hard, easy to grind, and sets fast.


1) Clean out the crack using a shop vac. Remove any dirt or oil residue with Super Clean.

2)Mix up the cement until it is a light to medium paste.

3)Pour it into a grout bag.

4)Wet down the crack with a sponge

5)Force the cement into the crack with the grout bag.

6)Trowel over with a 4" knife.

7)Within 4 hours, or immediately after it sets, grind it flush with a hand stone, available from any masonry supply or big box store. It's easy work before it cures.

8)Wait a week.

9)Clean and etch your floor for epoxy.


I've had no pull-up, tear out, or cracking in 10 years with forklift, pallet jack, and steel wheeled machinery skates traversing the floor on a regular basis.

 

[cvcman]

did you use epoxy paint ?? What brand ?? The steel wheels dont mark up the epoxy ?

The crack is only 1/8" wide could I just pour some epoxy paint in the crack first ??

 

[A_Pmech]

I used the Rustoleum Solvent-Base Industrial Epoxy. I bought a couple big-box stores out of it. At the time, it was a great deal compared to buying it in 5-gallon buckets and waiting 3 weeks for it to show up by truck.

Sure, steel wheels will scuff up the epoxy coating. It's a floor. That's supposed to happen.

Filling that crack with epoxy is an expensive use of $50 a gallon materials. Plus, it won't fill the crack. You'll still have a depression of varying depth where the crack was located.

Use the Hydraulic Cement. Trust me, it's an easy fix.

-Just remember, Hydraulic Cement sets F-A-S-T.

 

[cvcman]

where do you buy hydralic cement ?? Is it costly ??

My worry is if I fill the crack in will it crack someplace else or am I better off leaving it or using something flexable so the floor can move when its cold here ??

 

[A_Pmech]

where do you buy hydralic cement ?? Is it costly ??

My worry is if I fill the crack in will it crack someplace else or am I better off leaving it or using something flexable so the floor can move when its cold here ??

Hydraulic Cement is available at any hardware store or home center. It's cheap.

Your crack was likely caused by the contraction that takes place as concrete cures. It is a common problem in flat work. Filling it will not cause it to crack at some other location. If the crack continues to get bigger, it is a sign that the floor and / or the building foundations are in motion.

Most reinforced concrete operating within it's designed environment will crack. In fact, minor cracking on the tension side of bridge beams is expected and assumed. Concrete is very weak in tension and the reinforcing steel has a lower modulus of elasticity (lower "stiffness") than the concrete. Thus, the concrete will crack as the steel reinforcement "develops", or takes on tension.

So, there's really no need to worry about a new crack popping up in some other location.

 

[cvcman]

do you mix the hyd cement with water or is it premixed ?? Can I mix it runny to get into the crack. remember the crack is pretty narrow

Thanks

 

[Torque1st]

where do you buy hydralic cement ?? Is it costly ??

My worry is if I fill the crack in will it crack someplace else or am I better off leaving it or using something flexable so the floor can move when its cold here ??

The crack WILL flex and re-crack. Filling it in will have absolutely no effect on whether it will crack again or somewhere else. Prepare the crack as above but use a self leveling urethane concrete crack repair material available at most Home Box stores etc.

Epoxy floor coatings will scratch and chip when heavy objects scrape or roll across them or impact them in a working garage. Only the foo-foo wussy-caves so often depicted here on GJ and made just for show and beer spills look nice for long periods.

If you are worried about scratches and chips try a penetrating sealer. It will still scratch and chip but since the sealer penetrates it is not just a coating and the protection remains largely intact.

 

[Gotlift]

I have a pretty long crack in my garage floor that is up to an 1/8" in spots. I didn't stress too much about it. I just epoxy coated the floor and used the paint chip texture from the kit and the crack is barely even noticeable. Its not a big deal, just a crack but that's just me.

 

[A_Pmech]

The crack WILL flex and re-crack. Filling it in will have absolutely no effect on whether it will crack again or somewhere else. Prepare the crack as above but use a self leveling urethane concrete crack repair material available at most Home Box stores etc.

If the crack is a curing crack, or a compaction subsidence crack, it should not re-crack. If the floor is in continuous motion by that much, he has bigger problems. If the floor is stable at most it might reopen to a hairline in the middle of winter if he waits until August to fill it.

It also won't re-crack somewhere else simply due to filling it. It is highly unlikely that the repair will match the monolithic slab for tensile strength.

 

[A_Pmech]

do you mix the hyd cement with water or is it premixed ?? Can I mix it runny to get into the crack. remember the crack is pretty narrow

Thanks

You mix it with water.

Yes. You want to mix it to a light, runny paste, so you can force it though your grout bag. Mix it in a 1-gallon plastic paint bucket. Don't worry about getting the bucket clean, worry about getting it into the grout bag and into the floor. Wait until it hardens in the bucket, then flex the bucket and it will crack out in chunks.

Be sure to get the grout bag clean before it sets. Hydraulic Cement sets under water (thus it's name), so simply dumping it in a bucket isn't sufficient. You'll need a sponge and garden hose to get it clean.

 

[Torque1st]

If the crack is a curing crack, or a compaction subsidence crack, it should not re-crack. If the floor is in continuous motion by that much, he has bigger problems. If the floor is stable at most it might reopen to a hairline in the middle of winter if he waits until August to fill it.

It also won't re-crack somewhere else simply due to filling it. It is highly unlikely that the repair will match the monolithic slab for tensile strength.

He said the crack is about 1/8" which makes it a real fracture not a curing crack. It will always be a weak spot and even temperature and humidity changes can cause it to re-crack if an unforgiving material is used to seal it.

 

[nate379]

If it's cracked, that means the slab is/has flexed. Putting cement in the crack may force the slab apart more.

In other words, something flexable is the way to go. They sell tubes of caulk at pretty much any hardware store that is for concete for just this purpose.

 

[cvcman]

it is a floating slab, it is about 7" the same design used in Alaska. It has rerod and mesh etc. My Mom has the same garage but hers was saw cut and no cracks.

I have some caulk but its hard to get it into that small crack. I need something runny or again epoxy paint ??

 

[Torque1st]

Pay attention, go back and read post #8.

 

[cvcman]

pay attention,lol oh well ever try to caulk an 1/8" gap ?? It needs to be something runny, pay attention,lol

 

[StingRay]

Garage floor CRACK and tool ****. This place is going all to hell LOL

 

[nate379]

Sure, I just did a few cracks in my slab that were maybe 1/16" if that.

 

[cvcman]

Nate what brand did you use ?? Did you use a putty knife ?? How did the color match ?? Thanks

 

[Torque1st]

pay attention,lol oh well ever try to caulk an 1/8" gap ?? It needs to be something runny, pay attention,lol

IT IS RUNNY!!! That is why it is called self leveling. It is just thick liquid. Pay Attention!!!

And yes I HAVE caulked 1/8 and even 1/16" cracks with caulk. Easy as pie for someone with even a little skill.

 

[cvcman]

I assume you have " little skill" only kiddin'

How about a brand name so I know I get the right stuff.

Thanks

 

[Torque1st]

It has been a few years since I bought any but it is a common brand available at Home Depot or Lowes etc. It comes in regular caulk tubes. For floors it is labeled as self leveling URETHANE crack filler for concrete. It will be back where the concrete sealers, floor paint, etc are. There are two types made for horizontal (floor) applications or vertical (wall) applications. Both are urethane but you want the self leveling type used for horizontal (floor) surfaces. There are many other liquid crack fillers for floors but the URETHANE types seem to adhere well. DO NOT get it on your hands or clothes. A flexible plastic spatula will squeegee off any overfill or spills. Self-leveling means it is runny. It will fill voids so if you have any voids it may be advisable to fill them with sand so not as much expensive urethane is required to fill it. Just leave some space at the top of the crack for the urethane. Compressed air is useful in cleaning the crack as well as providing some space at the top of the crack for the urethane if the blowgun nozzle is aimed right.

 

[RustyBolts]

At Home Depot, they sell some stuff made by Sika that comes in a large sized caulking tube, and it's made just for filling cracks in concrete. It's urethane and light grey, and it's self-leveling. It works great. You just scrape and vacuum all of the crud out of the crack, then squirt that stuff in there slowly using a large caulking gun until the crack fills up, then let it dry a couple of days. It turns into a tough rubber. Since it's self-leveling, it makes a pretty professional looking repair if you're careful to not smear it outside of the crack. If the crack is too wide and too deep, you're supposed to cram some foam filler rod into the crack first so that you're just filling the top 1/2" or so with the goop from the tube. If you're careful and you fill the crack right up smooth with the surface, it levels out completely flat. It makes it really easy to sweep the floor once you fill in all the cracks and expansion joints with that stuff. Sometimes it'll droop down after the first application and you can add a little more the next day to get it up level with the surface.

Home Depot stocks that stuff in the aisle with other concrete related products. It's NOT in with the rest of the caulking products.

The urethane adheres well to the concrete, and it's stretchable or compressible so that when the concrete shifts around with the weather, it stays put and doesn't tear loose from it. Polyurethanes are paintable usually, so it might work okay under a fancy epoxy floor. I doubt there's anything else that would work better than that Sika stuff. I think they use it to fill expansion joints in concrete freeways even to keep water from pouring in between slabs.

 

[RustyBolts]

It has been a few years since I bought any but it is a common brand available at Home Depot or Lowes etc. It comes in regular caulk tubes. For floors it is labeled as self leveling URETHANE crack filler for concrete. It will be back where the concrete sealers, floor paint, etc are. There are two types made for horizontal (floor) applications or vertical (wall) applications. Both are urethane but you want the self leveling type used for horizontal (floor) surfaces. There are many other liquid crack fillers for floors but the URETHANE types seem to adhere well. DO NOT get it on your hands or clothes. A flexible plastic spatula will squeegee off any overfill or spills. Self-leveling means it is runny. It will fill voids so if you have any voids it may be advisable to fill them with sand so not as much expensive urethane is required to fill it. Just leave some space at the top of the crack for the urethane. Compressed air is useful in cleaning the crack as well as providing some space at the top of the crack for the urethane if the blowgun nozzle is aimed right.

Yeah, same Sika stuff I used and you must type faster than me. An air hose works okay, but I found out the best way to clean out the joints was to get an old ruined flat blade screwdriver and scrape all the **** out of the crack while holding a narrow nozzle from a shop vac right near the area where you're scraping. I had all kinds of olive pits and seeds and little pebbles and rusty nails and junk like that come flying up out of the crack. It's amazing how much junk gets stuck down in a crack in the concrete. Then I blasted it with nozzle from a hose and let it dry a couple of days, then I filled it with the Sika stuff. That stuff really does work well and looks like a pro did it.

I'd recommend doing that stuff in the summer. I don't think it works well if the concrete is damp at all.

 

[Torque1st]

I type fast, about half a day faster. Sika is not the brand I used but it is an excellent brand and will work well. If the concrete is damp the urethane may have a tendency to foam. If I remember right water is used for the blowing agent in urethane foam. But real urethane foam is a two component R/T chemical reaction urethane not a solvent base material.

 

[nate379]

Ok.
All I do is run masking tape along both sides of the crack. Run some caulk down the crack, use a 3"ish wide putty knife to make it level with the floor. Pull the tape and WHAM BAM, THANK YOU MA'AM all done.

Might have to wait for it to dry and go back again another times if the crack is fairly wide.

As for what brand, whatever the stuff as Lowe's is. It's next to all the concrete stuff.

 

[cvcman]

This crack is too crooked to tape jagged edges and crooked

 

[nate379]

Get the tape as close as you can... about all you can do.

Don't have to use tape even, but it looks better. I use tape when I caulk tub, sinks, etc as well since I'm not good enough to do it without.

 

[Torque1st]

Tubs and sinks caulk easily with man's oldest tool, a finger. Don't try it with urethane tho.