How to patch cracks/holes in poured foundation wall?


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Old 05-26-14, 05:07 PM
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How to patch cracks/holes in poured foundation wall?

My 44 year old New York house has some cracks/holes in the poured foundation wall. The previous owner tried to patch it at some point but his patch is flaking off. I'd like to remove his patch, repatch it and then paint the entire foundation. What is the best way to repatch it?

Mark
 
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Old 05-26-14, 09:36 PM
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Use a hammer and chisel to knock off all of the delaminated stuff that's there--and make sure you get all of it. Then proceed to install a quality, name-brand repair mortar (Quikrete makes a few of them). Follow the installation instructions on the package religiously, or you'll be doing it all again.

If it's a working crack, grooving or sawcutting a control joint at the crack location will provide a convenient place to seal with a pliable, exterior-grade caulking after the mortar repair has cured.
 
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Old 05-27-14, 02:03 AM
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1st get that **** off & post better pics of the crk,,, likely bridge's right but unlikely many can see thru the existing patch,,, we'll wait here while you do that

think of ' caulk ' as a verb - not a noun,,, we'll get to sealant materials when you get back
 
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Old 06-01-14, 07:38 AM
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I was able to get most of the original patch off with my hands (I'll make sure to get it all off before repatching it). Do these photos help with your recommendation on what to use to repatch it?
 
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Old 06-01-14, 10:45 AM
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is that rebar showing ? who's the dummie that put it there ? you need to remove it as the moisture's caused it to rust ( thereby expanding ) & then popping off block pieces

irc
 
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Old 06-01-14, 11:35 AM
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Yes it's rebar. Not sure who put it there. Just need to cut it out before repatching? Doing that won't hurt structural integrity?
 
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Old 06-01-14, 12:15 PM
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you must live up in poland its not doing a bit of good where it is &, likely, has caused the original problem,,, get it OUT !

1 other thing - its a conc wall, correct ? tnx
 
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Old 06-01-14, 05:17 PM
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Yes it's a poured concrete wall. Do you think the rebar runs the whole length of the wall? If so why is it only causing a problem in this 4-5' section? Or could it have somehow been installed only in this section during the first patch job?
 
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Old 06-01-14, 06:30 PM
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It could be somewhat localized.

The exterior grade is sloped and the deterioration is in the magic zone where moisture is available and can be absorbed while the surface goes through a lot of seasonal and daily freeze-thaw cycles that can occur more often. - Not as much of a problem below grade or further up.

The rebar, if it was original, really never did much good because it did not have enough cover. The cover usually should be 1-1/2 inches or more to have any structural effect. It rusted because there was not enough cover.

Any effects on the rest of the foundation might see some unusual cracks, but not likely since the rusted bar that was ineffective was really for continuity and to meet code minimums.

Dick
 
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Old 06-01-14, 06:57 PM
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The rebar looks to be original to the wall, and maybe just a short portion of it got pushed over to the outside forms when the wall concrete was vibrated. The left end of it in one of the pix looks like it veers back towards the wall interior. All it takes is a few missing tie wires and an over-zealous man on the vibrator to move bars or parts of bars from their intended locations during a concrete pour. I can't imagine anyone installing a rebar just below the surface when making a repair, but then again, anything is possible.

You can do some good by gently tapping the wall with a hammer, at locations where the visible rebar would be that's still buried. If it's too close to the surface, it will show up as a noticeable difference in sound (the delaminated concrete covering the bar will have a different-pitched tone to it, compared to concrete above and below the rebar). If you find delaminations, dig out and completely remove all rebar that's too close (less than 1") to the surface. In addition to spalling caused by corroding rebar, it can also be caused by the significant difference in coefficient of thermal expansion between steel (0.0000065) and concrete (0.0000055), per degree Fahrenheit. Made more pronounced by the bar being too close to the surface, and heating up more than the mass of concrete behind it, when the wall face is exposed to sunshine.
 
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Old 06-02-14, 10:01 AM
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Am I going to be able cut the rebar out myself? Or is that better handled by a professional mason? I don't want to make things worse.
 
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Old 06-02-14, 12:58 PM
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You don't need a "professional mason" to remove the rebar. Although many of them would gladly do it for you, for a hefty price. The quickest/easiest method of removal would be to use a 4" angle grinder, pushing the spinning (metal-cutting) wheel head-on into the bar at the point you want it cut. A cutting torch would also work, but there's a chance you'd do significant damage to nearby concrete with it.

Wear eye/face protection and some decent work gloves, as there will be lots of sparks shooting out at you. And don't worry about the over-cut made by the wheel into adjacent concrete, as the bond of your patching material will benefit from the interlock provided by it.
 
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Old 06-03-14, 02:23 AM
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anyone yet hazard a guess why that little piece of bar's there ? not aware of any code rqmt, dick - is there 1 ? tnx
 
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Old 06-03-14, 10:17 AM
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Take a look at the first paragraph of Post No. 10, for a possible reason why the rebar is there.
 
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Old 06-05-14, 03:08 AM
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forgot 1 thing & learned another: # 1, it was built by people i'll try to remember in the future; & # 2, posts have numbers

so why rebar like that ? 'cause some dummy did it - may have been moved by poor wiring or over-vibration but the steel shouldn't have been there in the 1st place imo,,, obviously once placed, care should've been given,,, around doors & windows is another circumstance

tnx, bdge
 
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Old 08-24-14, 12:32 PM
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Finally got all the previous repair material and rebar out today (life gets in the way sometimes!). I cut one end of the rebar with a grinder, then was able to get behind it to loosen it and then the other finished end just popped out without me having to cut it. What's the best material to fill the crack? The deepest point of the needed patch is about 1" (in groove left by the rebar). My father in law recommended Top and Bond but will that work on a vertical surface? Everything I found on it showed it in use on flat surfaces and really watery at application. Is there something else I should look at? Will want to paint it white along with the rest of the foundation. Name:  photo(1).jpg
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Old 08-24-14, 02:30 PM
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You need to do a better job of cleaning the rusted debris from the concrete, in the rebar indentation. Patching with any decent product is not likely to permanently bond to the parent concrete, because the patch material will bond to the corrosion products still there, and pull away when they let go of the concrete. If you don't believe me, just take a screw driver and push hard while dragging it in the indentation--you'll see the rust products flaking off.

I'd hit it using an angle grinder with either a wire wheel or just a masonry blade. You want to make it "clean enough to eat off of," as I used to tell my inspectors.
 
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Old 08-24-14, 03:53 PM
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Ok. Once the groove is cleaned out better, then what type of product should I use to patch the wall?
 
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Old 08-24-14, 04:57 PM
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I'm tagging this thread so I'm alerted to further replies. Good info.
 
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Old 08-24-14, 06:45 PM
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I've been out of the concrete repair business too many years, to recommend what would work best among currently available products. Take a photo of your area to the nearest masonry supply place, where they will be able to make "best product" suggestions for your situation. They will also have a better selection of suitable products than typical big-box stores usually carry.

Another thing to consider for long-term performance of your repair is to run a shallow (1/2" deep) sawcut around the perimeter of the repair area, and chip out all of the material delineated by the sawcuts. Doing so eliminates the feather-edges of the repair product, with more mass of material to stay permanently bonded. If you slightly angle the sawcuts from the vertical, inclining the saw blade towards the center of the patch, the resulting "wedge effect" will also further promote the repair concrete staying in place.
 
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Old 08-25-14, 06:27 PM
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impo, the best vertical/overhead polymer-modified repair mortars are 'just add water' mixes,,, i like 1" deep but, nevertheless, sawing the perimeter makes the patch more acceptable visually, promotes better adhesion, & makes finishing easier,,, roughen up the sides of the sawcut as the diamonds in the blade will slightly 'hone' the sawcut & you need rough instead,,, troweling from the center of the patch to the perimeter will lessen edge shrinkage i'd look 1st @ a const supply house rather than masonary altho i don't know your local stores' genl inventory
 
 

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