Concrete repair ideas and advice

My cracked concrete front porch won over the voting masses in this week’s “Pick My Project” poll. What an eyesore!


I’ll be honest — this was not a fun job. It’s important to patch bad concrete, though, because with winter coming, damaged bits will only get worse. That’s because when it freezes, moisture in the cracks expands into ice, flaking the surface even more.

The good news is that there are a lot of good inexpensive products available for patching busted concrete. The chemical formulations have advanced to produce stronger, better looking results than plain old concrete, and if your spot to fix is small, ready-mixed patching formulas will make your job a lot easier.

First, you must clean. As with so many home improvement projects, preparation is key.


Chisel and bang and pry out all the loose bits. Tell yourself you’ll get a manicure with the money you save doing this hard-on-your-hands job. Use a hoze with a nozzle to blast out the tiniest rocks. If you are brave enough to take this a step further, you can use a diluted muriatic acid solution to further clean the surface.


Muriatic acid is not for weenies. It is highly caustic and you have to be really careful about how you use it. I applied the diluted solution with a throwaway sponge brush. This is the first time in my adult life I applied the high school lab lesson of pouring acid into water and not the other way around.

Applying the acid caused fizzing. Sort of like when you spill 7UP. If you inhale the fumes it can burn your lungs, so it’s no surprise it also kills plants.

The point of using such a strong acid is that it etches the surface and makes it chemically more prepared to bond with new patch material. I talked with a guy who pours a lot of concrete this week, and he highly suggested using it. There are other, less caustic alternatives, but they are very expensive and I couldn’t find much feedback about their effectiveness. I was just really careful and only poured what I needed. One other muriatic acid tip — go to a smaller hardware store and you can buy it in smaller quantities. Home Depot only sells this in huge 5 gallon 2-packs in the garden dept. I bought a little bottle at Lakewood Ace Hardware for about $2.50.

Here is the cleaned out crack. Yikes!


After cleaning the crack it’s time to patch. I recommend buying premixed patch if your job is small. My crack was too big for that, so I bought a 40 lbs bag of Quickrete Concrete Patch at Home Depot for about $10 and mixed it up with water using a shovel in a 5 gallon bucket. This is VERY hard work. When your back is about to give out and the consistency is that of grainy peanut butter, you have 30 minutes to work with the material. I used a small trowel to pack and smooth the patch.

The end result is not perfect but it is better than it was. A day later it is still drying, as you can see here. I plan to stain the porch in the next couple weeks, so hopefully that will smooth out the variations in color.


All of the photos from this project are posted here on my Flickr account. Happy Patching!


6 responses to “Concrete repair ideas and advice

  1. It looks like you did a very professional job. What color of stain are you planning to use on the porch?

  2. Pingback: 34words » Blog Archive » Concrete repair ideas and advice

  3. If you have any extra brick from your house, you could fit it in the hole created by the intercom, then use your concrete skills to fill in around it.

  4. Do you think I should pry out that piece of metal? It seems pretty stuck.

  5. Pingback: Damaged concrete as high art « erin covert * hands on

  6. Well, it’s early February 2013. Time flies !
    How is your patch job holding up? I have a similar situation and need to get my porch fixed or replaced this year.

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