Author Topic: How would you fix a hole in a cinder block wall?  (Read 2950 times)

Monocle Money Mouth

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How would you fix a hole in a cinder block wall?
« on: February 17, 2019, 08:13:12 AM »
Several years ago, I needed to have my breaker box and sub-panel rewired in my basement. I had to take down some 1960's vintage rumpus room wood paneling so the electrician could get to the conduit that linked the two boxes and run some additional conduit. When I pulled down one section of paneling, I found one of the previous owners got lazy with the wiring. At one point, there was a junction box with a light switch mounted to the cinder block wall. Instead of removing the junction box and rewiring everything so it would fit behind the paneling, he just knocked a hole in the cinder blocks for the foundation and pushed the junction box into it. I attached a photo to illustrate.

I've ignored this one for years because I wasn't sure how difficult it would be to try to fix on my own. Fortunately, the cinder blocks are not part of an outside wall. There is a cinder block wall that divides my basement in two. This is on the dividing wall.

At some point, I would like to get rid of the rest of the wood paneling, fix all the little pock marks from removing masonry nails, and paint the cinder blocks a glossy white. Since this would be exposed, I want to  make sure it looks right.

Has anyone ever had to fix something like this before or have any ideas for how to fix it properly?

Thanks!
« Last Edit: December 08, 2021, 10:11:57 AM by mies »

Rob_bob

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Re: How would you fix a hole in a cinder block wall?
« Reply #1 on: February 17, 2019, 05:59:36 PM »
Probably mortar mix or cement.  Mix it thick and built it up from the bottom of the crack.

Reynolds531

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Re: How would you fix a hole in a cinder block wall?
« Reply #2 on: February 18, 2019, 06:48:19 AM »
After you fix it's a good bet texture wouldn't look right. If that's an issue check home depot for two part epoxy tile refinishing mixes. Can't recall the brand.

Gone Fishing

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Re: How would you fix a hole in a cinder block wall?
« Reply #3 on: February 18, 2019, 07:08:15 AM »
Type N mortar, mixed with just enough water that it smooths out and is not crumbly.  Use your finger, spoon, or other tool that matches the contour of the joints to put in faux joints.  For the nail pocks, I am not sure the mortar would have enough adhesion, try it, working it in to the pock firmly, but if it doesn't work, I'd just use drywall compound.  If it matters, you might find some type of texturing tool to roll over the repairs to help them match.  Don't rule out play dough or pastry tools, just play with them and see what you can do.

Monocle Money Mouth

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Re: How would you fix a hole in a cinder block wall?
« Reply #4 on: February 18, 2019, 07:51:12 AM »
Thanks for the suggestions guys! I’ll look into that.

Cadman

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Re: How would you fix a hole in a cinder block wall?
« Reply #5 on: February 18, 2019, 09:23:59 AM »
You're going to need some sort of backer board or all your mortar is going to slump to the inside of those blocks. There are some 1/4" thick tile backer boards that can be cut and snapped like drywall that you could slip through the hole and pull flush from the inside. Wire or screw them in place using a 1x2 or piece of rebar across the front of the hole; this should hold them until your mortar sets, then remove the wire/rebar and fill those voids.

Fishindude

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Re: How would you fix a hole in a cinder block wall?
« Reply #6 on: February 18, 2019, 11:02:57 AM »
Get that conduit and box out of the way, stuff the big void full of wadded up paper so you don't need a ton of mortar, then patch with stiffly mixed masonry mortar.
Buy a cheap sponge trowel and finish it flush with block surface.

Monocle Money Mouth

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Re: How would you fix a hole in a cinder block wall?
« Reply #7 on: December 08, 2021, 10:28:47 AM »
So it took me a couple of years to finally address this, but I got the hole in my basement wall filled. I had some leftover Durham's Rock Hard Water Putty left over from another project. It said it can be used to patch concrete. As an experiment, I used it to patch the pock marks and hole from my original post. I was going to try the mortar option, but I couldn't figure out a way to put a solid backer behind the hole.

I put down an inch of putty let it dry, put on another layer of putty, and repeated that until I was done. I had to sand it and refill some low spots a couple of times. I also had to sand in the mortar joint. It seems to be solid so far.

It will still be several months before I have a chance to paint it, so I can monitor how well it holds. If the putty doesn't hold, I'll go back to the drawing board.

Ladychips

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Re: How would you fix a hole in a cinder block wall?
« Reply #8 on: December 08, 2021, 03:12:50 PM »
I LOVE updates like this. Thanks for sharing. Looks good!

GuitarStv

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Re: How would you fix a hole in a cinder block wall?
« Reply #9 on: December 08, 2021, 03:18:16 PM »
Looks great!

Monocle Money Mouth

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Re: How would you fix a hole in a cinder block wall?
« Reply #10 on: December 08, 2021, 06:22:00 PM »
Thanks! I thought this needed some closure. It'll look even better with some paint. The putty dries different colors depending on how thick it is. The dark spots are the thick spots that stuck out from the wall that I needed to sand down. The lighter spots are the low spots that got filled in. Even though the color looks a little crazy, it is flat, smooth, and level with the rest of the block.

I'm planning to take down the rest of the wood paneling in my basement between Christmas and New Years. I discovered there are two layers of wood paneling on the walls after taking off an old phone jack 😑 I hope that is the only surprise I find.
« Last Edit: December 08, 2021, 06:24:03 PM by mies »

Monocle Money Mouth

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Re: How would you fix a hole in a cinder block wall?
« Reply #11 on: December 24, 2021, 09:41:10 AM »
For people that like before and after photos, I demolished more of the wood paneling in my basement.

There were 2 layers of wood paneling. The original layer had flood damage. The bottom 3-4 inches was discolored and some panels were crumbling. Unfortunately for me, the previous owners decided to just cover up the damage instead of tearing it out and fixing it for real. Or acknowledging the fact that finished a basement in an area with a high water table isn't a good idea and you should come to terms with the fact that you need to leave the blocks bare 😑 Basements in this part of town need to be left as mechanical and storage rooms.

The wood they nailed to the foundation blocks along the floor was also rotten. Some of it crumbled as I was taking it out. On the bright side, at least they stapled Romex to it. I like to keep my electrical cabling wet and covered in mold.

I also found 2 more holes in the cinder block walls. One had a receptacle in it. I'm guessing the other one was probably meant to have the outlet but they measured wrong. Solution: Break another hole in the wall.

I moved the receptacle up, added another one, and routed everything though EMT. I was hoping to avoid hanging conduit since I still need to paint, but I didn't want cables dangling from the ceiling to the floor either. On the bright side, I can dismantle the conduit before painting and reattach it when I'm done. The hard part of measuring, cutting, and making sure it's all level and plumb is done.

In some ways this looks worse. All the water damage stains are exposed. You can see more of the ceiling damage that was covered by trim. There are tons of spots from me patching nail holes and even though the big holes are smooth and flush with the block, they still look weird because of the sanding I had to do. I'm happy to have the rotten wood out of there and the holes repaired. It's a conceptual improvement and will be more functional, healthier, and safer.

Sibley

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Re: How would you fix a hole in a cinder block wall?
« Reply #12 on: December 27, 2021, 10:50:01 AM »
Much improved.

Just be careful with painting it, if you've got water coming through the foundation then paint can trap it in and worsen the problem. Not sure how that applies to cinderblock (I know brick), but keep it in mind.

Monocle Money Mouth

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Re: How would you fix a hole in a cinder block wall?
« Reply #13 on: December 27, 2021, 11:15:28 AM »
Much improved.

Just be careful with painting it, if you've got water coming through the foundation then paint can trap it in and worsen the problem. Not sure how that applies to cinderblock (I know brick), but keep it in mind.

Thanks! One of the previous owners waterproofed the foundation and had drains installed in the window wells around the house. We haven't had any issues with water seeping through the walls since we have owned the house. The other side of the basement was painted more recently and that has held up fine.

It's going to be at least a couple of months before I even think about painting. I can monitor the bad corner to see if it still has water seepage but I think we'll be ok.

 

Wow, a phone plan for fifteen bucks!