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dgbehrends 10-10-2008 03:56 PM

Advice needed for filling large basement Cracks
Hello and thanks for reading,
Please move this over to the flooring category if it doesn't fit here.

My 4.5 year old basement had some large cracks in it when I purchased my house 1 year ago. I was concerned about these cracks and a vertical crack on the wall and hired a structural engineer to investigate before I made my purchase. The engineer said the cracks were cosmetic and would not cause any future structural problems. I think the cracks were caused by a frost heave but its hard to be certain. The basement is 1300 sq/ft and the concrete is not scored in any location. Anyways, I would like to fill these cracks before I lay some carpet down. It's just some spare carpet with no pad under it, just a temporary solution until I finish the basement some years from now.

My solution to fill the cracks is to add some fine filler sand to the wide cracks and use the crack filler stuff I bought at Menards (see picture below) to seal it..

And now finally for my question:
Is this the right way to do this, or is there a better approach?

Termite 10-10-2008 07:56 PM

You need to fill the cracks with an epoxy crack filler, and you won't get it at Menards!

Simpson is one reputable brand.

This isn't something you want to put a filler in. You need your fill material to be as strong as the concrete, thereby eliminating the weak point.

My way will be much more expensive, but it is the way to do it. :yes: It would cost more to have a pro come in and do essentially the same thing.

dgbehrends 10-10-2008 10:20 PM

Thanks for the pointer. That looks like the stuff to fix my cracks the "right way". I have 2 concerns with it though.
After reading some of the documenation on it, I found this page
and read down to this statement
"In situations where the crack completely penetrates the member (e.g. concrete slab) the material may continue to run through the crack into the subgrade. In these cases epoxy repair may not provide an effective repair."

and also on the same page

"In situations where the crack penetrates completely through the concrete element and the backside of the concrete element cannot be sealed (e.g basement walls, or footings with backfill) longer injection time may not force the epoxy to the next port. This most likely indicates that epoxy is running out of the unsealed back side of the crack. In this case the application may not be suitable for epoxy injection repair without excavation and sealing of the back side of the crack."

I know in the spring I actually had a few worms come up through the crack, no water though. From the looks of my crack its probably all the way through the slab for at least a portion of the distance.

They also say this "Simpson Strong-Tie does not recommend repair of cracks larger than 1/4" wide without consulting a qualified engineer."
Yikes! :eek: That particular crack is wider than 1/4" in some places.

My other concern is that because the house is still relatively new the basement might not be done settling and this could reopen the crack.

I would need to buy the 22oz dispensing tool ~$60, some nozzles ~$9 and several 22oz Gel and Low Viscosity Epoxy ~$33 meaning I would be looking at up to and possibly over $200 for finishing this up. Like you say still much cheaper than hiring someone to do it, plus I have a cool new gun I can use to help, or lend to friends and family.

I think this is the way to go when I finish the basement, what I'm not sure of is this is the right thing to do now?
Adding some filler sand is definitely out of the question now. I want to get it sealed but if I seal with the cheap stuff can I take that out and do it the right way several years down the road potentially after all the settling has finished?

Edit: and it looks like Lowes and Home Depot carry this stuff, however Home Depot's online store said they were out of stock.

HandyPete 10-10-2008 11:11 PM

"cosmetic"? you sir have a real problem. If you think calling a pro, and spending a few hundred bucks is tough, your in for some big surprises.

Good fondations don't "settle" nor do they crack, yours has problems.

get professional help!


KHouse75 10-10-2008 11:28 PM

You are going to get some settling with most houses. Concrete cracks. That's why they put in control joints in large concrete pours.

Sometimes cracks are due to undersized footings, poor soil, organic debris under the soil, etc.

If the cracks aren't getting larger and have stabilized, your house isn't going to go anywhere.

With cracks like that, I fill them with sand until it's about 3/8" below the surface. I then take self leveling polyurethane concrete caulk and fill the cracks.

dgbehrends 10-10-2008 11:29 PM


Originally Posted by HandyPete (Post 170755)
"cosmetic"? you sir have a real problem. If you think calling a pro, and spending a few hundred bucks is tough, your in for some big surprises.

Good fondations don't "settle" nor do they crack, yours has problems.

get professional help!


Before I purchased the house, I had a structural Engineer inspect the cracks and sign off saying they would not cause foundation problems down the road. If he is wrong then his insurance is going to have to pay. I agree with you that good foundations don't settle or crack. My foundation is not "good", but that doesn't mean it has to be excavated. I can't think of too many unfinished basements I've been in where I didn't spot a crack.

dgbehrends 10-10-2008 11:31 PM


Originally Posted by KHouse75 (Post 170765)
You are going to get some settling with most houses. Concrete cracks. That's why they put in control joints in large concrete pours.

This basement desperately needed some control joints. *sigh*

dgbehrends 03-06-2009 07:07 PM

I decided to use the watertite sealer and it seemed to create a nice flexible seal. What I didn't realize was that after it cured it was very sticky to the touch. After walking over it a lot the stickiness has gone away. In the large crack above, I used some foam backing rod to prevent all of the sealer to run through the crack. The smaller cracks I just puttied over.

yesitsconcrete 03-07-2009 04:43 PM

don't have time to get into this now as we're head'd out to dinner,,, just hope you have that engineer's signed/stamped report in writing,,, more tomorrow am.

dgbehrends 03-07-2009 06:38 PM

I'll be here and eager to read your comments, even if I don't like them. :)

Some other things to note about my situation is that the foundation was built somewhere between sept 03 and jun 04, the height of the building boom meaning fast eddie was probably doing the cement work. This winter which was our second in the home, I noticed another large crack show up in a spot where I didn't really expect it. Granted the basement is 1340 sq/ft with no joint control but it sure looked like a frost heave, which might have been what caused the crack in the picture above. I did some downspout work last summer to keep water away from the house and the sump pump doesn't run much if at all. One thing I do know is that my neighbors sump pump runs a lot (so he tells me).

My limited experience tells me it's either a frost heave or settling. I believe the engineer said it was settling, but I would have to double check the report.

dgbehrends 11-17-2009 12:08 AM

I decided to use the watertite stuff in my first post. I used backing rod for the larger cracks. The stuff works pretty good, it sealed all of my cracks up and is flexible so any additional settling doesn't lead to an opening. The only thing I didn't like about it was that it was very sticky to the touch even after it had dried. I used a clear coat of paint on areas where I walked to avoid any problems.

stadry 11-17-2009 04:23 AM

apologies for the delay,,, btw, that was certainly some dinner :laughing: didn't notice any control jnts in the floor,,, conc slabs like to be square & i'd bet those crks're from it trying to relieve the forces of tension,,, still need to have 'em & renting a gear-drive circle saw w/diamond blade should take care of it easily enough.

btw, surprised your pe didn't pick up on that,,, in the future, saw prep the crk so the sealant has the proper depth:width ratio ( should find it on the tube OR w-site ),,, some sealants're aerobic while others're anaerobic ( cure w/air / cure w/moisture )

nevertheless, nice work by the unitiated :thumbsup:

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