# Compacting soil without disturbing footing



## dielectricunion (Feb 27, 2013)

I have a short retaining wall that I built beside a shallow footing so that I could dig out my crawl to a reasonable depth.

Backfilling and compacting (by hand), I started to notice the vibration disturbing the shallow stone footing that I'm trying to stabilize/preserve.

Any tips on how to compress this soil without too much vibration? I plan to top this knee wall off with some crushed stone and 4+" concrete.

I assume the answer will be "excavate the original foundation and rebuild it with a footing to proper depth". I was tempted to do that but this is work I'm doing in my own house and I need to stop adding projects so I can get back to paying jobs.


----------



## dielectricunion (Feb 27, 2013)

...


----------



## jaydee (Mar 20, 2014)

water


----------



## dielectricunion (Feb 27, 2013)

jaydee said:


> water


I'll try it. Definitely not going to tamp anymore


----------



## tgeb (Feb 9, 2006)

I would just fill that area with #57 stone and be done with it.
I would not use water as a tool for compaction. :no:


----------



## owattabuilder (Sep 2, 2013)

Use lean concrete to fill the void instead of soil. They will batch a 1 bag mix that is like a 500 psi mix. They can make it flowable soit fills all voids. It is used a lot for utility trenches under streets.


----------



## dielectricunion (Feb 27, 2013)

I need to order 3+ yards of concrete for the slab so i guess i can get enough to backfill that area. The situation is not ideal but i need to find a reasonable compromise.


----------



## dayexco (Mar 4, 2006)

dielectricunion said:


> I need to order 3+ yards of concrete for the slab so i guess i can get enough to backfill that area. The situation is not ideal but i need to find a reasonable compromise.


personally, i wouldn't dump three yds of concrete in there. some poor bastard will have to hammer that out someday. i'd go with the pea rock.


----------



## 66 Shelby (Jan 11, 2009)

dielectricunion said:


> I need to stop adding projects so I can get back to paying jobs.


Ain't THAT the truth (especially when you're married) :laughing:


----------



## dielectricunion (Feb 27, 2013)

dayexco said:


> personally, i wouldn't dump three yds of concrete in there. some poor bastard will have to hammer that out someday. i'd go with the pea rock.


The 3 yards is for the small slab over that crushed stone (with vapor barrier between) ...but I did planning on pouring a slab over my compacted backfill behind retaining wall to seal it up. 

I definitely think that same way though "what happens when some poor bastard needs to change something here..."


----------



## cdkyle (Jul 12, 2009)

Did you mention what you were backfilling with? Its looks like gravel. If I'm not mistaken, you can achieve 95% compaction just with placing the clean stone, no compaction needed. Presto, problem solved.


----------



## dielectricunion (Feb 27, 2013)

cdkyle said:


> Did you mention what you were backfilling with? Its looks like gravel. If I'm not mistaken, you can achieve 95% compaction just with placing the clean stone, no compaction needed. Presto, problem solved.


I have #7 crushed stone a few inches deep across the whole space but I didn't order enough to backfill the entire trough. I used the clean fill that I dug out of the crawlspace to backfill. The soils here are heavy on the clay so it's mostly clay. 

I wish I didn't have to backfill so much but I needed to leave myself space to lay the block while still getting close to the shallow stone footings.


----------



## dielectricunion (Feb 27, 2013)

...


----------



## tgeb (Feb 9, 2006)

Just fill the space with stone, and when you do the slab, let the concrete pour down into those empty cells and fill that wall.

If you have footing movement of the existing now, you may need the extra strength of a solid wall. Reviewing the photos, it "looks" like you may have undermined the existing foundation.

Get that thing buttoned up before you have some issues.


----------



## cdkyle (Jul 12, 2009)

^What Tgeb said.^ More gravel. :thumbsup:


----------



## BattleRidge (Feb 9, 2008)

dayexco said:


> personally, i wouldn't dump three yds of concrete in there. some poor bastard will have to hammer that out someday. i'd go with the pea rock.



LOL Im that guy some guy is definitely going to be cussing later on. We joke about that all the time.


----------



## S.R.E. (Apr 8, 2010)

owattabuilder said:


> Use lean concrete to fill the void instead of soil. They will batch a 1 bag mix that is like a 500 psi mix. They can make it flowable soit fills all voids. It is used a lot for utility trenches under streets.


Here we use "CDF" Controlled density fill which is like lean concrete with no stone. The best part is it will flow, you don't need to compact and you can dig it with a shovel.


----------



## fjn (Aug 17, 2011)

Many moons ago,we placed 88 semis of this stuff in a 7,000 sq.ft. foundation supporting a slab on grade poured floor. Had it tested,lab.said no compaction would be needed,33 years later no settlement. Actually got it free,just paid trucking.



http://www.blackbeautyabrasives.com/products/black-beauty-original-abrasives.php


----------



## dielectricunion (Feb 27, 2013)

fjn said:


> Many moons ago,we placed 88 semis of this stuff in a 7,000 sq.ft. foundation supporting a slab on grade poured floor. Had it tested,lab.said no compaction would be needed,33 years later no settlement. Actually got it free,just paid trucking. http://www.blackbeautyabrasives.com/products/black-beauty-original-abrasives.php


Damn!


----------



## brhokel606 (Mar 7, 2014)

Very glad to see you slugged the block work! Very nice. 

I would also just gravel it. You could pin the top when you do the top slab to keep it from dropping even if the ground settled a bit. With it being interior I would not do that if frost heave was an issue but interior you should not get frost heave. 

Or just put in the dirt, put down 2" foam over the dirt and pour your slab pinned to the wall on the slugged walls. I would add a few more slugged wall for the support though.


----------

