Garage/Shop Floor - Patching & Paint?

[KC7CN]

My garage/shop floor has a lot of cracks. Can anyone share their experience with patching the cracks, and painting the floor?

* What kind of paint did you use? (Low-cost garage floor paint from Wal*Mart, more expensive Epoxy's, one or two part)

* What did you use to fill the cracks?

* Does the paint cover the cracks so they can not be seen?

-Don

 

[Gotcha6]

Crack repair in concrete is very dependent upon the size of the crack as well as the direction of movement. Small cracks can sometimes be repaired with unsanded tile grout. Use sanded grout on larger ones. If the crack shows a vertical displacement from settlement below, you won't be able to fill it in smoothly. It would still show a ledge. In that case you may want to use a 'crack chaser' on a had grinder to vee out the crack and then go from there. Another important thing to consider is does the concrete still move? All concrete will shrink & crack. The better laid concrete has this fact planned into it. If a crack occurs at 8-10 foot intervals, this is normal. You'd want to seal this crack with a polyurethane caulk - not silicone or latex. Poly caulk will expand up to 300% and help keep water out from beneath the slab, the principal cause of a crack causing eventual slab failure. Just be sure the crack is clean & dry.
As for painting, I've only used one product there and that was the H & C concrete stain. It gave good results, but I'm sure there are better products on the market today.

 

[Douglas Robinson]

Dear Don:

I used Rustoleum Epoxy Shield. It comes with instructions. The fllor must be cleaned. I would not use the colored dots again. You will have to patch the cracks before applying the paint (which is two part epoxy paint),

Doug

 

[KC7CN]

Dennis, thanks for the suggestion to use polyurethane. I have a box of cement patch that I got from my Dad; cement looking powder you mix with water. I have no idea how well it works.

The floor has a lot of cracks because my contractor did a lousy job; It was hot the day they poured, and he did not stay around to use a hose to keep it cool. The slab is 24x28, and they did not put in any expansion slots when they did the job -- they came back later, and used a saw to cut them in (after the floor cracked). The cracks are all at surface level and the floor is flat.

Doug, Did you have to patch any cracks before you painted the floor?

Thanks for the assist.

-Don

 

[Gotcha6]

I've been pouring concrete off & on around 35 + years. Finishers have to be careful about too much water too early. Concrete needs very little water to set and the remainder to make it workable. Too much water weakens the mix, and water placed on the surface during finishing should be done sparingly and only after the second float pass or during final finish.
It is a common practice to saw expansion joints 24-36 hours after pouring, but no more than 48 hours after pouring. Concrete shrinks as it hardens and it will crack pretty much where it wants if it's not sawed to at least 1/4 to 1/3 of its total depth. Unreinforced (no wire or rebar) concrete should have expansions at 10-15 foot intervals. Reinforced concrete can go over double that. A sawed expansion provides an area for movement to take place and the rough nature of the break below the saw joint provides an area of maximum contact to avoid vertical displacement. If your cracks are hairline and spidery, they are called 'crazing', and the cement grout you have should handle them. I'd certainly use the polyurethane on the sawed joint, though. Dust, dirt, etc. entering this crack will push a slab apart eventually with temperature cycles.

 

[sapwood]

Don,
At the suggestion of one of our staff, our Webmaster (Monty) has setup a new forum for "workshop planning and setup" related posts. Your thread appears to be a perfect candidate for the forum, so I moving this thread to "Workshops" . . . you will be the first to post in the new forum :mrgreen:

HTH,
Roger

 

[DaveO]

Don,
At the suggestion of one of our staff, our Webmaster (Monty) has setup a new forum for "workshop planning and setup" related posts. Your thread appears to be a perfect candidate for the forum, so I moving this thread to "Workshops" . . . you will be the first to post in the new forum :mrgreen:

HTH,
Roger

What a great idear, I didn't know where to put this thread earlier. That seems most appropriate :-D :-D

Dave

 

[KC7CN]

Dennis -- thanks for the informative explanation on concrete floors. I'm not at home at the moment to verify this, but I'm pretty certain the saw cuts are fairly shallow, about 1/4". They fill up with sawdust, and I clean it out with the shop vac. I like your idea to fill them with the poly.

Roger, Dave, --- I wasn't sure exactly where this post should go, so I just guessed! You really had me going there for a little while -- just a little dizzy form all the jumping around :-?:drunken_s:lol:. But I have to say, to be the 1st. post in the new Workshops formum is an honor! :eusa_danc:eusa_danc:eusa_danc:eusa_clap:eusa_clap

-Don

 

[DaveO]

Don, we're all a little dizzy, creation of a new forum or not :lol: The beauty of this site is if you want to see it going in a certain direction, just ask. We are very open to suggestions that will make this better place to find the information that you're looking for, and how to ask the right questions in the right place.
Dave

 

[Douglas Robinson]

Don:

My house was built in 2002 and the floor had no cracks that needed patching. Good luck and post some pics.

Doug