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Block or solid concrete retaining wall?

MohavValley

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Looking at pushing my back slope back (slope is downhill in to my back yard) to put in a 33'w x 36'd building (not sure stick or metal yet) in my back yard.

I want to build the rear wall of the structure on top of the retaining wall to increase the front set back of the building so I have the max room between house and building and more open concrete work space.

I ran a laser and from existing grade and the back slope is not square on the left side wall/ property line which it's up against. So left side retaining wall will be 4' and the right side wall will be 7'6", grade is close to 2:1.

I've pulled city standards for retaining walls and anything over 5'4" they call for 8" wide block wall with 12" wide solid fill base that's 24" high and a 36" wide key with 12" deep center, two sets of 2 #4 beam bonded, X &Y bars @24".

I'm thinking of maybe doing this as a single pour (or 2 pour if better?) Concrete Form wall instead of block.

For the guys that do this or have done it is the form wall, stronger, easier, cheaper VS. the block wall?

Suggestions & sub referrals welcomed I'm in Corona.

Thanks
 
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TCHB

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i Have both and would go with block.
 

DC-88

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Block= Cheaper, but if done correctly works fine. Be sure to waterproof/ drain sheath, and drain back side with drain at bottom of footing depth regardless- In our area the soils engineer would be weighing in on the design to the structural engineer for the job.
Concrete= typically stronger in 8" width depending on reinforcement
 
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Nordie

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If it even meets code for your building to sit on the retaining wall, if I read that correctly. I would say concrete is going to be the way to go, and it's probably going to require some columns. I would honestly call an engineer.

I really haven't seen CMU be retaining over 4-6.
 

MohavValley

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I really haven't seen CMU be retaining over 4-6.
I assume CMU is cement block?

I figured block wouldn't be able to hold back that much dirt or support the building and it has so many steps VS. building the forms and just doing one big pour plus I can use 5k psi (7-8 bag) concrete if I can get it in the form with a snorkel and or vibrators (not your kind grads).
 

Nordie

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I assume CMU is cement block?

I figured form pour would be able to hold back that much dirt or support the building and it has so many steps VS. building the forms and just doing one big pour plus I can use 5k psi (7-8 bag) concrete if I can get it in the form with a snorkel and or vibrators (not your kind grads).

CMU=concrete masonry unit=block

I don't know what codes you are dealing with, but there is definitely limitations on CMU. There is definitely more reinforcement that can go into block to help, but I would imagine if you want the back (I'm guessing) of your building to sit on the retaining wall, cast in place concrete would most likely be required (this will be the foundation of your building).

Also you're going to have to factor in your easements as well, how close is this retaining wall from the end of your property.

I would definitely talk to an engineer.
 

MohavValley

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CMU=concrete masonry unit=block

I don't know what codes you are dealing with, but there is definitely limitations on CMU. There is definitely more reinforcement that can go into block to help, but I would imagine if you want the back (I'm guessing) of your building to sit on the retaining wall, cast in place concrete would most likely be required (this will be the foundation of your building).

Also you're going to have to factor in your easements as well, how close is this retaining wall from the end of your property.

I would definitely talk to an engineer.
Slope is in to the back of my yard so I'd be cutting in to it. Rear prop line is 8-10ft and left side property line is 3 feet.

And yes retaining wall would be the foundation of the buildings rear and back 10 feet of side walls.

Wall would be 9' tall across back but only retain 4' on the left and it'd slope up to 7'6" on the right and extend forward 3' from back before it starts to drop as it comes forward.
 
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TCHB

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Concrete walls crack.
 

Your ad here

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Take some pictures. The wall may be 4 '- 8' tall but the footing may have to go deep in order to prevent a side load on an existing structure, if one is present.
 

NicPaus

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I have both at one of my jobs. Over 4.5 is all poured in place. Retaining that the house sits on. Highest point is 8' with 4' key rebar 8" oc. Cmu is faster less forms. But the engineer spec was cmu up to 4.5 then poured in place.
 

MohavValley

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Take some pictures. The wall may be 4 '- 8' tall but the footing may have to go deep in order to prevent a side load on an existing structure, if one is present.
Closest existing anything is neighbors directly behind pool at 35'-40 to property line at top of hill and neighbor catty-corner's pool at 25'+ to neighbors to my lefts back property line.
 

DLC

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if permitted or not I would stop in and ask some questions at your local building dept, if no permit one of your neighbors might rat you out, it happens.

ask about retaining wall and a load bearing cmu, it might bite you down the road if it’s not built correctly

I would go cmu document all steel with pics and plan on going one or 2 block higher along the back for waterproofing.
waterproof block and down onto top of footing ( when pouring footing try to float out the back side of footing semi smooth with out a lot of big humps bumps so its easy to roll on waterproofing) and add foam backer board protection to protect waterproof membrane and a French drain with rock and filter cloth.

your top anchor bolts might need a horizontal bar to lock in the AB for your 2x4 or 2x6 treated bottom plate
 

Melloyellovector

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Talk to engineer. You will need Details specific to your project.

Yes you can go over 6 ft w CMU, we do 7ft pretty frequently, you would be using 12 or 16in block for lower half of wall. No way in hell a city standard even remotely ok for wall w structure on top. Also note you can’t even do wall on its own and build structure on top of walls footings. You either engineer collectively or keep completely separate.

Corona you will need minimum 5ft set back side yard, and min 5ft possibly 10ft in rear yard.

Likely engineer will require huge footing with poured in place wall on hillside. Pouring footings then doing block, then pouring other footings / foundation would be cost prohibitive. Money saved on one step will raise costs on other steps.

Form and pour it all.

Just for reference for special engineering, permits, grading work, foundation work w retaining walls, to the point of concrete poured Your gonna be 40k plus. And that’s just through concrete. No water proofing, no drainage and fill behind, No electrical, no plumbing, no framing, no roofing.
Hope your budget matches your dream. :eek:
 

grumpy88

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Do any of you guys do block retaining walls in Las Vegas ?
 

badluck

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Pour in place concrete. But that’s usually 2 pours. 1 for 4’ wide footing and 1 for the wall. 2 pours means 2 separate pumps and finish crews. Cmu is at least 2 pumps probably 3. 1 for footing and 2 for 2 lifts. I feel like you need to excavate more when doing a pour in place. We just did over 150 ‘ of 6-10’ tall walls. Double sided wall forms, single sided, and shot Crete. All had different challenges. Pour in place looks the vest and I think is the strongest. Shotcrete might be stronger but what a mess and Pía. Engineering, soils test, permits, you could be in it 25k before you pour it. We had 1/2 rebar 4-1/2” o.c. And we were dealing with straight rock. Every bit had to be dug with a breaker on an excavator. I was in it well over 50k and did it all. Drawings excavation forms pours and finish. Had friends help along the way. Good luck!
 

WYRD

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Talk to engineer. You will need Details specific to your project.

Yes you can go over 6 ft w CMU, we do 7ft pretty frequently, you would be using 12 or 16in block for lower half of wall. No way in hell a city standard even remotely ok for wall w structure on top. Also note you can’t even do wall on its own and build structure on top of walls footings. You either engineer collectively or keep completely separate.

Corona you will need minimum 5ft set back side yard, and min 5ft possibly 10ft in rear yard.

Likely engineer will require huge footing with poured in place wall on hillside. Pouring footings then doing block, then pouring other footings / foundation would be cost prohibitive. Money saved on one step will raise costs on other steps.

Form and pour it all.

Just for reference for special engineering, permits, grading work, foundation work w retaining walls, to the point of concrete poured Your gonna be 40k plus. And that’s just through concrete. No water proofing, no drainage and fill behind, No electrical, no plumbing, no framing, no roofing.
Hope your budget matches your dream. :eek:
Spot on.
 

Pelon

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You are not just retaining 4 to 7 ft, you are retaining to the top of the slope, and an engineer will design for that. Form and pour, as others have said. To much rebar to efficiently do block.
 

Wheeler

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You could use block. These were not very expensive and came out of Fontucky. About 2700 lbs. each.

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Nordie

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Any names you can suggest
I usually deal with commercial so bigger masonry companies. One that does come to mind is maybe call XL masonry, they're commercial, but might do residential.
 
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