I’m building a cement block garage “24 x 32” on a hillside, hard-packed dirt. A foundation of 30 x 10 poured cement. I would like to know would 3-inch crushed rock compress better than 1/2-inch crushed rock for filler under my concrete floor? The cement blocks are for the foundation only, I will stick-build the rest of the structure. The back wall out of the foundation is 10 feet in height, the front wall is 2 feet, so a lot of fill is required.
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The back wall out of the foundation is 10 feet in height, the front wall is 2 feet, so a lot of fill is required.
You need an engineer to design this. Really.
I assume you are using 8" or 12" block? Filling the cores and including steel? Even with that, without doing the calculations I would not be confident that wall would support the fill or structure.
You are essentially building a retaining wall. A 10' retaining wall generally needs a lot more than just a wall to support the soil or fill.
You really, really need to talk to an engineer. If you have been having trouble getting foundation contractors to quote it, it's because they don't want to touch it for liability reasons.
Maybe the wall at this point is ten feeet high, but will only be backfilled to 5-6 feet - all we can do is speculate! Oh well.
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no, I myself would fill with sand.
LOL, that's because all you have in Florida is sand!;)
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83181.2 in reply to 83181.1
Originaly posted in reply to "foundation" in general discussion. "I am not an engineer nor an excavator.
However I would look at sand, 3" rock ,unless it is 3" minus, meaning it has smaller rock and "fines" with it, (not enough "fines" and rock will not lock into place.) will not compact very well in my opinion. Perhaps there is an excavator or engineer here who can give all the reasons. My experience (and I have done a lot of jobs requiring large amounts of fill) is that the smaller the particles of the fill the better. Fill is placed in small lifts and compacted as you go. The amount of the lift is determined by the fill and the size of the compaction equiptment.
I hope that you have had that tall wall engineered, that much fill being compacted is going to generate large lateral forces on the walls."
its cheap. at $2 a yard. I used it everywhere
I know, it drains and compacts fairlywell too. BTW, it would cost me $28/yd for fill and $44 for masonry quality
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it rin $1.50-$2.00 a yard plus $50 deleivery fee. so 100 yards about $300
It's officialI hate you!;)
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$2 per yard? I pay ten times that.I might send a train your way.
choo-choo!
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
<LOL> No ##### -- I don't think I can buy anything for $2 a yard.In fact, I'm not even sure I can load anything for much less than that.Oh ##### -- do we have to pay to load the train or is that included in his price? <G>
hard to answer because "dirt" is what you sweep up off the kitchen floor. If you rdirt is damp clay, I'd drive those larger rocks into it or remove it and use 18" of mixed sand gravel compacted in 6" lifts.
I assume you mean a footer thirty inches wide and ten inches deep for "foundation"
A footprint that large on such a small building implies some poor quality soil is why I assumed you might have some softer stuff.
if so, with a tall wall on the back, you will need more quality fill than just the fifty some yards for infill in the middle. wet clay for backfill outside will destry a block wall prety quick.
So - say more about what kind of soil you have and where this is being built for bewtter comments.
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I wouldn't backfill that any more than the footer trenches.
Get an engineer to give you plans for a suspended floor.
SamT
Now if I could just remember that I am a businessman with a hammer and not a craftsman with a business....."anonymous". . .segundo
I gave you a long reply on the other post of this same discussion, so I will keep it brief.
Are we to understand that you have an eight foot drop across this site?
The 10 foot direction or the 30 foot direction?
Woodturner is right -- you really, really need an engineer. No joke.
I am an excavation contractor; I generally work on fairly difficult sites and almost always work under geotechnical and structural engineering inspection. I develop most of my own materials specifications and methods of work and work closely with engineers for approval.
I'll answer any questions I can within reason, but if you take nothing else away from this discussion, if you are planning on building on a site that has eight feet of fall across 30 feet (or 10 feet) and you are planning to backfill a 10 foot tall block CMU wall, you need an engineer.
And crushed stone of any size does not sound like a good idea to me for this application.
Say it again and again. Engineering needed.