best option, pressure grout ? 1

[dbuff]

I work in logistics engineering, but hope for help in your line of work. Someone here said pressure grouting is voodoo?
Is this a poor option?

Have crack in basement slab floor of house, all the way across basement. I am close to having cement based grout pressure injected. The crack gets larger each year going from 1/16 to 1/8 to 1/8 to 1/4 over 5 years.

drilled holes in foundation, drove steel rod down 3 feet easy. foundation is thin at approx 2.5 inches thick.
no water seepage.

Better options? Many Thanks.....

 

[Focht3]

Nothing personal, but - Yuck!

The slab is too thin; and a Portland cement grout won't do much more than fill the crack. Epoxy grouting is preferred, but won't fix the underlying cause of the crack. It's likely a new crack will appear in a few years - close to the existing ones.

You need to hire a local geotechnical consultant to find out what's going on...

 

[dbuff]

wow. thanks for quick response!!

just to make sure - opinion is "pressure grouting" not good idea for soil stabilization?

if i get stable soil then crack stop from getting bigger, right?

since slab too thin , what are option on this 5 year old house? bought new ,will builder fix?

Thanks again!

 

[Focht3]

It sounds like you need to hire a lawyer to help you sort things out. In most states, the builder is on the hook for ten years. You have two years after "finding" the defect to file suit. I'm not a lawyer - that's a very abbreviated summary of my "legal" knowledge on construction defects.

If "pressure grouting" is being proposed to stabilize the soil, where are you? (I'm not a big fan of this technique for most repairs.)

It sounds like your problem is much greater than fixing a few cracks. Please give us a more detailed description of what has occurred.

 

[dbuff]

Thanks for your intrest. House located Atlanta, GA.
The builder has to blast rock to make basement and then backfilled (red clay dirt) some. Perhaps the soil was not compacted well enough?

only one crack, but
The crack runs from front of house and back of house.
Crack was "within tolerance" when house bought. Builder to do nothing then.

5years later...
There has very tiny bit of deflection in some areas along crack. and crack is bigger at 1/8 to 1/4 width all along.

I have had several folks out to look at it and all said not to worry about it and just fill crack. To be on safe side
one guy said he would drill a few holes and see how much penetration he could get by driving a steel pipe into ground. He was surprised how far it would go with ease.

He is pressure grout sales person, so his solution of course is to pump grout under pressure into holes on a grid in order to "stablize" the underlying soil to stop further cracking. Then suggest expoxy to fill crack.

I dont think this is groundwater mgt issue. No water has ever come thru the crack and I am not having sheetrock crack or doors binding, so is not big deal. at least not big deal yet. I was to finish basement, so i want to fix problem/cause of crack.

I sincerely appreciate your help. Is there other type info i can provide?

Regards,
DON

 

[TJWATKINSPG]

Atlanta is a cool town. The Brevard Fault runs right through the city from the northeast to the southwest. The soils to the southeast (except for Stone Mountain) are mostly clayey sands. The soils to the northwest are mostly metamorphic sediments. Because you mentioned that there was some blasting required I'm guessing that you are some where to the northwest edge of town. If the backfill that the contractor used in your basement is from the decayed rocks north of town the possibilty of shrink/swell clay crops up. If the movement is related to surface water runin then you might find the movement to be seasonal. This sounds like an interesting problem(glad it's not my home though) I personally would ask another opinion about injection grouting.

The truth will set you free. Best of luck. Geodude

 

[doc11]

Sounds like a compaction issue. Many of the builders there will compact their fill by running over it a few times with a front end loader and call it good. This was going on 15 years ago when I moved from the Atlanta area, and I noticed a builder doing it his past winter when I went back to visit family.
I would follow Focht3's advice and hire a geotechnical engineer to find the problem and reccommend a solution.

 

[nackra]

what is potential for perched groundwater with resulting hydrostatic pressure?
were foundation drains used?
Groundwater impact: I had a project where rock excavated for tanks - created "pool" where groundwater accumulated in the excavation some 12-feet deep in rock (perched groundwater seeped thru clay overburden and fissures in shale/limestone rock strata). Added foundation drain to dewater excavation - excavation "dry" after drain installed

 

[dbuff]

you guys are great. thanks for complement on atlanta, grew up here. no beach, but we cant have it all.

yes i believe foundation drains used.
have two corregated black plastic pipes that exit low side of house. builder said keep them clear and hope you never see water come out of them. i have not noticed any.

as far as good engineer in atlanta area, best place to locate one that is right for the job? perhaps geotechnical associations?

just a question on builder responsibility if you dont mind. if slab is poured at less than code , are they responsible to fix this type issue?? i think whatever fix , it will be expensive.