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Germwise 06-30-2010 02:03 PM

How to Repair Cinder Block Foundation Cracks
Just stumbled onto this site. I love the forums and will definitely be lurking around learning as much as a can. I have some questions regarding my next project though.

I recently bought my house. During inspection, I noticed there were some cracks in between the corner cinder blocks right under a damaged gutter downspout.

I hired a professional structural engineer to come take a look and he said there wasn't much movement that that I shouldn't worry, the house was structurally sound.

He mentioned that to avoid water seeping in, I should dig a trench around the area, and fill in the cracks with the proper material and do the same on the inside of the finished basement wall.

I've been working around the house for many months now repairing many things. This however will be my biggest project.

I'm rather at a complete loss a to what I have to do. My Plan was as follows.

1)Dig Trench around corner of house, 8 feet alongside largest wall and 2-3 feet along other wall to confirm no damage there.

2) Use Pressure washer to clean wall and cracks thoroughly and allow to dry

3) Seal cracks with ??????

4) paint whole cinder block wall with dry lock or similar to avoid any moisture getting in.

5) cover trench again and do same on inside walls after ripping off dry wall.

My questions are:

*Should I try to dig by hand? if so how long will this take me? What are the requirements/costs involved in renting a small back hoe? What if I hire a bunch of workers to help me dig?

*Is my plan as outlined above OK? should I powerwash? What material should I use in cracks?

*Sealing the cinder blocks seems precautionary. Still, is dry lock enough or should I look into something else?

I am a poor college student and I've been doing a lot of work to the house to add value and maybe come out ahead in another 2 years when I move to my final job. I'm willing to work and unless its undoable, I would like to avoid hiring someone to do this.

I'm looking for some photos and I'll add them as soon as I can. Any advice is appreciated.

Thanks for all your help guys!

stadry 07-01-2010 05:02 AM

what a pita block walls are :censored: otoh, we do make a good living repairing 'em :thumbsup: you mean ' concrete ' blks & NOT ' cinder ', right ??? its critical as cinder blks rot & collapse,,, 1st, are the crks just lateral ( horizontal ) in the mortar OR do the follow the vertical mortar, too ( ' step cracking '),,, a crk THRU a block(s) different but we still want to know.

' much movement ' means he can't see your house from his house 'cept he's got some initials after his name :laughing: you should worry - it IS your house ! ! ! bet he worries about his, too :yes:

water seeping IN can ONLY be stopped outside,,, from the inside, its called ' water management ' &, usually, includes a sump & pump !

seal exterior cracks w/fiber-reinforced roofing cement followed by a layer of ( miradrain/delta drain ) forget the ' dry lock ' as it isn't & never does,,,
we rarely use machines to dig - inside my 4 guys can rip out, install, & cover back 50' on an avg day of french drains.

poor is prudent @ your time in life
:wink: unfortunately, this administration's working against you to KEEP you poor for the rest of your life,,, so how'd you get to own a house ?

jomama45 07-01-2010 10:08 AM

I'm mostly with IRC on this one (except for his hatred of CMU walls! :wink:).

Hand digging is probably the way to go, unless of course you were a professional excavator in a past life. In all seriousness, you can do more damage to yourhome with a mini excavator in 10 seconds than you would believe. If the soils aren't extremly dense, hand digging is probably a good option.

Fix the cracks on the outside with a Type M mortar and flush the wall up so it's semi-smooth to accept the foundation coating.

No Drylock, no excavator, no beer til ypur done digging............:thumbsup: :laughing:

Germwise 07-01-2010 10:33 AM

As for owning the house there were some incredible programs $100 down, 2500 in closing costs paid, extra 500 for realtor, and 10 pct back.

I had been saving for many years for a downpayment and instead I have been using it to repair the home.

Been resetting the windows, installing hardwood floors. Repairing the walls, the siding the plumbing etc etc.

I think there are step cracks since there is a little movement in the wall (the structural engineer poked a camera through the dry wall and measured with some string on the outside.)

I don't really have water coming in too much since my house does have a sump pump system. I do notice a small rust spot right at the corner on the inside of the basement (its a bi-level home) but its been completely dry ever since I repaired the downspout.

I'll try to take some pictures this weekend and post them up. I'll try to dig and maybe cover with a tarp. I am doing this alone with a 20 dollar shovel. Maybe I'll trick some friends or pay some people to come dig with me.

Thanks for the advice!

Germwise 07-01-2010 11:14 AM


Thanks for your answer. I am not a professional so I had to google some of your terms.

Miradrain is a kind of a plastic cover that will drain away the water? Where do I buy this? will it come with installation instructions?

Also when that is done, should I put a french drain? considering this was due to just the downspout is that worth it? and is there a website I can read on how to make one?

Thanks for all your help!

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