Crack in cinder block foundation

Reply

  #1  
Old 02-12-10, 12:19 PM
Member
Thread Starter
Join Date: Oct 2007
Location: USA
Posts: 117
Crack in cinder block foundation

I'm (still, always) working on my basement renovations. After power washing the walls I found several hairline cracks in various places. They are all small and none go through to the outside. I found a tube of Quikrete concrete repair product at Lowes, followed the directions and sealed them up. So far so good.

One crack, however, is larger than the rest. It includes a small hole and, through that hole, you can see daylight outside. Would it be possible/feasible for me to simply shoot some expanding foam into the hole, let it set up, then fill the crack with the Quikrete product?

Here's the crack in question. The hole is near the bottom; the second image shows a close-up of the hole, with me holding a AA battery for scale.



 
Sponsored Links
  #2  
Old 02-12-10, 01:26 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
Use expanding cement, not expanding foam. It's also known as hydraulic cement.
 
  #3  
Old 02-13-10, 09:10 AM
Member
Join Date: Mar 2009
Posts: 7
A vertical crack like that is a structural problem.

Step cracks are usually caused by minor settling but a verticle crack is a sign that a rock or boulder may have hit the wall during backfilling.

You may have to add soldier beams or pilasters for support
 
  #4  
Old 02-13-10, 10:50 AM
Member
Thread Starter
Join Date: Oct 2007
Location: USA
Posts: 117
Originally Posted by Pulpo View Post
Use expanding cement, not expanding foam. It's also known as hydraulic cement.
I have most of a bucket of Drylok "Fast Plug" which I used to patch a damaged and weeping section of the wall elsewhere in my basement. The label says says "Hydraulic Cement" on it, so I assume that's the right stuff?
 
  #5  
Old 02-13-10, 11:12 AM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
I guess so. I didn't know that Drylock made it.
 
  #6  
Old 02-13-10, 01:44 PM
Join Date: Mar 2005
Location: USA
Posts: 6,130
Those are not the old cinder blocks, but are concrete block or concrete masonry units in codes and product specifications.

How old is the wall?

Is there any movement of the center of the wall at the top, midpoint and bottom using a string line run from end to end? - You will have to set the ends of the string out from the wall to measure the difference at the midpoint of the wall length.

Vertical cracks are not always a structural problem, especially if they are not appreciably wider at the bottom than they are at the top.

The only 90% positive structural indication is a horizontal crack.

The pattern and the width variations are good indicators of the type of crack. Using the indefinite word "may" is just an opening to a foundation repair man looking to keep his men and backhoe busy. Usually, rocks in the backfill shows up very quickly after backfilling.

If you really think it is a structural problem get a structural engineer out before asking a for opinions and alternate solutions before contacting a foundation contractor.

Dick
 
  #7  
Old 02-13-10, 04:37 PM
Member
Thread Starter
Join Date: Oct 2007
Location: USA
Posts: 117
@Concretemasonry....

The wall is the foundation, and the house was built in 1976, so there you go.

There is no movement from the top to bottom, using the method you describe. Or at least, no movement that I could perceive through those measurements.

I really don't think it's a structural problem, mainly because the house is ~35 years old and there's no indication ANYWHERE of water damage, soil leakage, or anything else. The crack is perfectly clean and the surrounding concrete is unstained. I am, however, going to have two inspectors come in and take a look. It won't cost me anything for an appraisal and if they say it's fine just patching it up, I'm happy with that. Otherwise, I'm in trouble.

Pulpo: It's this stuff:

 
  #8  
Old 02-13-10, 04:56 PM
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,986
That's the stuff.
_________________
 
  #9  
Old 02-13-10, 06:15 PM
Join Date: Mar 2005
Location: USA
Posts: 6,130
That is the long time proven classic for repair of concrete cracks that are not live or recent. You will never find a dam without it becaue is works even if the wall is damp, not like caulks.

Hydraulic cement is a generic material that many people slap their brand on. It has been around for well over 80 years since no one has come up with a better repair because it works well with concrete and the environment (materials and moisture).

Your "free" inspectors should be qualified and not tied to a foundation contractor. A structural engineer gives opinions and alternates and is done with that if he is a professional. A home inspector is not qualified to suggest repairs, but only to red flag a potential problem and then suggest contacting a real professional. If a home inspector does not give you 1 or 2 contractors to contact, he is probably not certified or has alternate reasons.

Dick
 
  #10  
Old 02-15-10, 05:50 PM
Member
Thread Starter
Join Date: Oct 2007
Location: USA
Posts: 117
Originally Posted by Concretemasonry View Post
Your "free" inspectors should be qualified and not tied to a foundation contractor. A structural engineer gives opinions and alternates and is done with that if he is a professional. A home inspector is not qualified to suggest repairs, but only to red flag a potential problem and then suggest contacting a real professional. If a home inspector does not give you 1 or 2 contractors to contact, he is probably not certified or has alternate reasons.
I had an inspector come in today. Happily, the township I live in provides free inspections under certain circumstances, which I happen to qualify for. So I didn't get a contractor recommendation because of "unfair bias" (owing to being hired by the township) but I do believe I got a fair appraisal.

The verdict is: The crack is not compromising the structure of the house and can be easily patched. So today I mixed up some hydraulic cement, poured it into a makeshift pastry bag, and squeezed a bunch of it into the hole until it started pushing back out. Then I filled the rest of the crack and that was that. Problem solved.

Thanks, all.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes