Step repair


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Old 04-05-12, 07:37 PM
Tolyn Ironhand's Avatar
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Step repair

I have a buddy who has some steps that are crumbling on the corners, and he asked me about repairing them. I have not see it first hand but he sent me some pictures. It appears that there was some carpet glued to them at one time. Anybody have suggestions on a repair plan and/or what products to use? Anybody have had any luck with this?:QUIKRETE« - Repairing Concrete Steps



 
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Old 04-05-12, 10:30 PM
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I've repaired a few concrete steps in my day. Along with many hundreds of other concrete structures (bridge girders, abutments, diaphragms, etc.).

Here are a few things I learned (some the hard way):

1. I prefer delineating the edges of the repair with a 1/2" deep sawcut, then chipping out the waste to avoid a feather-edge. Even though the Quikrete reference you linked says their products are good for feather-edges, that's usually not true, as such edges will be the first places to break off and fail.
2. Make sure any loose or hollow-sounding concrete in the repair area is removed, again by chipping with a small impact hammer. Blow off the dust.
3. For the step corners shown, using concrete with minus 1/2" aggregate is the way to go. A pre-packaged mortar will not have the strength or similar physical properties as the surrounding concrete. For such small jobs, I like pre-packaged Quikrete 5000, "sweetened" slightly with some Portland cement.
4. A troweled on repair (in layers) is NOT the way to go. Far better to slap corner forms on (2 x 8s work well) using concrete nails or Tapcons. Wet the forms just before dumping in the stiffly-mixed concrete. Tap the forms with a hammer to help work out entrapped air, consolidate and finish the top with a mag or resin float.
5. I prefer to use a "neat" (meaning just water and cement) Portland cement slurry for a bonding agent. Brush it onto the roughened concrete that you've pre-wetted earlier, just before dumping in the fresh concrete. You can spend more for fancy acrylic or epoxy bonding agents, but they won't work any better than the neat Portland.
6. After placement, cover things with plastic for an hour or so, then carefully strip the forms when your thumb doesn't make a dent when you push down on the new patch areas from the top. Mix up a small batch of cream (more Portland cement slurry), and use it to rub the faces of the repair areas, getting rid of any small voids that will be there after the forms have been stripped. A rubber float works well for this. Hit all corners with a 3/8" or 1/2" edger to make it pretty. Then give everything a nice stiff broom finish before putting the plastic back on for a day or two.
7. For corner repairs, it helps to enhance the bond of the patched concrete by first drilling in 1 or 2 lag bolts with expansion anchors before the forms go on. Leave the bolt heads stand clear a half-inch of so, making for a good grip of the patch to the parent concrete.
8. Don't do this type of repair in direct sunlight if possible, but also wait for warmer weather to keep things above 50 degrees F. for a few days for best results.
 
  #3  
Old 04-06-12, 12:43 PM
Tolyn Ironhand's Avatar
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Thank you Bridgman for all your helpful info!
 
 

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