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-   -   Large crack in foundation.. Options.. (http://www.diychatroom.com/f19/large-crack-foundation-options-100285/)

Timothyv 04-02-2011 12:58 AM

Large crack in foundation.. Options..
 
Well was going to work on my room in the basement. Took the old wall down and found a nice crack running from the window down to the footing. I've read that epoxy or urethane is the way to go. I cant see that. The crack starts about 1/8 inch wide at the top. Ends up being 3/4 inch wide at the bottom. I guess I would out where the water is coming from when we get a good down pour. For as long as can remember.. cracks should be fixed from the outside.

Was thinking about digging down to the footing from outside. Clean 2 feet on each side of the crack. Some sort of rubberized sealant rolled on. Then place a rubber membrane on top of this.

Is this a correct way to do this? Which products? Other ideas?

Thanks guys. Tim.

jklingel 04-02-2011 01:38 AM

Tim: 3/4" at the bottom is huge. Have you looked at WHY there is a crack that large? House settling? How old is the house, and what is the composition of the wall? Agreed: fix from the outside, and why not mortar it in, then cover w/ a gooed-on rubber membrane?

Timothyv 04-02-2011 06:39 AM

The house was built in 62'. I'll bet the paneling I took off the wall was from then. From what I can tell this is a common type of settling crack. Started at the corner of the window cut out of the concrete. Judging by the stains it has been here for a very long time.

As soon as the spring melt is over I'll start digging. What type of mortar do you suggest? and while we are at it.. membrane and sealant. I've read all kinds of posts and web sites and there are so many different products to use. Not sure if I can use it but I have half a roll of ice dam membrane left over from my low slope roof. Wonder if I can use that..


Anyways thanks for the reply.. Tim.

jklingel 04-02-2011 02:08 PM

"From what I can tell this is a common type of settling crack." It may be common, but it sure ain't a good sign. That is a huge crack. I don't recall the exact ratios for the mortar I'd use, but it would not have gravel, of course. Something like 3 parts sand, one part cement, and a quarter part lime. Any concrete place can give you exact ratios. For membrane, I don't see why bituthene would not work, if the block is cleaned well. There also may be a sealer/primer goo that would help it stick and fill in the block pores as well. I don't have any specifics. I'd sure keep an eye on that crack over time, too. If it keeps going, something radical needs to happen, if not now, IMO.

Aggie67 04-02-2011 08:26 PM

I do structural inspections for a living, from houses to high rises. I wouldn't let a 3/4 inch foundation crack go without looking into it further. They can turn into total nightmares.

jklingel 04-02-2011 09:48 PM

Aggie: Good to know I was not worried over nothing. Thanks for the input. j

jklingel 04-03-2011 12:25 AM

Tim: I made some assumptions just to get a rough calc, and it is possible that your foundation has settled nearly 12" to get that crack. If anyone is curious, post up and I'll share what I did. It is hard to believe you need that much drop to generate that crack, but that is what the numbers show.... unless my brain is not calc'ing what my mind's eye sees. The point is, you have some settlement there. Have you noticed any separation between studs and bottom plates, or walls buckling, floor sloping, or anything else to indicate settling? Not to scare you, but I am suspicious of a large problem waiting to bite you.

jomama45 04-03-2011 11:48 AM

Quote:

Originally Posted by jklingel (Post 622126)
Tim: I made some assumptions just to get a rough calc, and it is possible that your foundation has settled nearly 12" to get that crack. If anyone is curious, post up and I'll share what I did. It is hard to believe you need that much drop to generate that crack, but that is what the numbers show.... unless my brain is not calc'ing what my mind's eye sees. The point is, you have some settlement there. Have you noticed any separation between studs and bottom plates, or walls buckling, floor sloping, or anything else to indicate settling? Not to scare you, but I am suspicious of a large problem waiting to bite you.

I'm not sure how it's possible to do the math w/o knowing the exact height of the wall and the length of the effected wall. I'll bet dollars to donuts it's not 12" though....................

jklingel 04-03-2011 02:18 PM

Quote:

Originally Posted by jomama45 (Post 622324)
I'm not sure how it's possible to do the math w/o knowing the exact height of the wall and the length of the effected wall. I'll bet dollars to donuts it's not 12" though....................

Joe: As I said, I made assumptions to get a rough idea. Here is what I did, and I am sure that the settling is not quite exactly like I assumed, and his numbers are a tad different. I, too, was surprised at the distance of "settlement", which could also be other things, like the end walls moving apart a tad. I assumed the end walls had not spread, and that the "settling" was uniform on both sides of the crack. See if my brain was operating correctly. Take two sticks, each 15' long (180"), and lay one on top of the other in front of you, so they stretch out left and right. These are the bottom of the cracked wall. On the left end, mark the ends A and A'. On the right end, B and B'. Drive a nail through B and B', and then swing A' along the ground until it projects a perpendicular line back to A-B that is 3/8" from A; half of the crack. That gives you a right triangle with hypotenuse of length 180", one side of length 179.625" (along A-B), and the short, projected side of length x. Pythagorean Theorem calcs x = 11.6". The question is, how much do these assumptions represent the house? This is just one possible scenario; somethin' ain't right here.

Timothyv 04-03-2011 05:22 PM

Well this is what I get for sending my wife to measure this crack. Back home now and checked it out. The average width of the crack is 3/16th's. When I sent her down to measure she measured it like I told her. Find the widest part and measure that. Well it was a small chuck that was missing. (Chunk is oval shaped about 2.5 inch long and 1/2 inch wide. The crack is nowhere near as bad. Being on the road makes it hard to double check things.

Wow the things you guys can do with math.

Anyways.. "Have you noticed any separation between studs and bottom plates, or walls buckling, floor sloping, or anything else to indicate settling"

Studs and plates are fine. Floors along this wall and corner are 1/16" from perfect using a 4 foot level along with a chalk line. When I removed the old studs and plates they were a snug fit along the wall. Beginning to think that this crack was here when this house was built. I will go over and ask the father in law.. he was a teenager when his dad built this house and see what he knows.

jklingel 04-03-2011 09:38 PM

Well for God's sake, 1/16th inch ain't Jack Stink. Problem solved. Oh, and I won't comment about why women can't measure properly. It's something about being lied to about a certain measurement. :laughing: BTW: Joemama; when do I get my doughnut?

jomama45 04-03-2011 10:06 PM

1 Attachment(s)
Here you are................. :laughing:


Attachment 31606

SPS-1 04-03-2011 10:27 PM

Quote:

Originally Posted by Timothyv (Post 621637)
Was thinking about digging down to the footing from outside. Clean 2 feet on each side of the crack. Some sort of rubberized sealant rolled on. Then place a rubber membrane on top of this.

I have had similar cracks profesionally repaired, and that seems like what they have done. I suppose this is a DIY forum, but I would vote for calling in a pro. They came in sometime after I left for work, and were finished before I got home. And they gave me a warranty.

stadry 04-03-2011 10:38 PM

when all is said & done, there's usually more said than done :yes: fix the crack from the outside as you posted - we use sonneborn sololastic buy you can use roofing cement, too,,, protect it w/membrane & compact the backfill in 4" lifts,,, on the inside, spread some hydraulic & ck it from time to time,,, if it cracks, you've got more movement so call in a pro,,, 12" my patoot ! ! ! if the foundation had dropped 12", you couldn't pour a full cup of coffee to go along w/the donut :laughing:

Timothyv 04-04-2011 12:18 AM

Father in law said it cracked soon after the house was built and there should be one more on the other side of the basement. This is kinda good news as this should mean that all the settling should be done after 49 years. :) The bad news is I have another hole to dig forsure.

Roofing cement you say. I have almost a full bucket left over from redoing the roof last year. Wonder if I can use the left over ice barrier for a membrane.

Thanks again all. Tim.


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