Backfill Question

[ShawnHenrySpencer]

Yet another foundation question. I have a dilemma I’m trying to figure out. I have a stepped footer on grade. 3 blocks on the high side, 8 blocks high on the lowest corner. 8” block is doweled every 3 feet 6” into footer (high strength epoxy) and to the top course, and all cells of every block are filled to the top (3500 w/fiber). Total measurements are 24’x32’. No ladder wire was installed. I feel like we’re good to place 57 stone and pour, buddy says I need brick the foundation and backfill outside before we backfill slab. Is this really necessary?

 

[mike93lx]

Are those only 4" block? From what I have seen, those are only use when bricking. Otherwise, it would be 8" and then parged

 

[Renegade1LI]

Looks like 4" block with metal ties for brick veneer. I would definitely complete the masonry, remove organic material prior to back filling. Make sure to backfill evenly on both sides of the wall, also make sure to fill the cavity solid behind the brick.

 

[ShawnHenrySpencer]

They are all 8”, except the starter course being 12”. Top is 8” cap block

 

[ShawnHenrySpencer]

Are those only 4" block? From what I have seen, those are only use when bricking. Otherwise, it would be 8" and then parged

12” bottom course, 8” up from there, 8” cap block on top

 

[ShawnHenrySpencer]

Here’s a better photo of block

 

[mike93lx]

12” bottom course, 8” up from there, 8” cap block on top

The block that we can see the top of in your circle really looks like it's 4". You are saying that is 8"?

Edit, the new Pic helps.

So it looks like it was setup for masonry, but if you have 8" block the whole way up, I'd expect you can skip it if desired

 

[ShawnHenrySpencer]

Will definitely brick it. But my buddy thinks we need to do that before backfilling and pouring the slab. For added strength. It’s a bit out of order as the entire garage will be bricked so I’d be having the masons out now, then framing and back again is overkill to me. Should I be worried about loading the whole thing with gravel and pouring as it stands now?

 

[Renegade1LI]

New pic helps, really looked like 4",lol.

 

[mike93lx]

I don't think the brick will add any strength in that direction. If the block is filled, I expect you are fine

 

[NUTTSGT]

It's going to be a royal PITA but that grass and topsoil need to come out before back filling.

I would try to fill both sides equally as you go since you have 8 courses on part of it.... at least if it was miy, that's what I would do as to not push a wall in or out.

 

[Renegade1LI]

My biggest concern would be with compaction, even using all stone you still need to properly compact. The more you could backfill the better, if not consider bracing the higher walls. We brace 8' poured concrete foundation walls until the deck is in place, there's no side to bracing.

 

[Firebrick43]

Block won’t add much bet you definitely need to be balanced on your back fill.

Add a foot to the outside and a foot to the inside and so on or you very much can blow out the wall. Remember to compact the outside and not just the inside.

Also don’t use rock with fines like 57. Use number 8 clean stone in 4” lifts and compact.

And yes, the topsoil and grass should be removed

 

[NUTTSGT]

Brock won’t add much bet you definitely need to be balanced on your back fill.

Add a foot to the outside and a foot to the inside and so on or you very much can blow out the wall. Remember to compact the outside and not just the inside.

Also don’t use rock with fines like 57. Use number 8 clean stone in 4” lifts and compact.

And yes, the topsoil and grass should be removed

57's around here are about 3/4", no fines.

Stone/gravel, sizes are a regional thing.

 

[jack stand]

Block foundations have been gone for well over 20 years in my experience due to these concerns. You say 8 courses at the tall corner, 64" +/- . I'd think about backfilling the outside half of that height then adding your stone inside.
Has anyone mentioned to you "grade beams" or a poured or block series of posts out in the slabs "field"? You have your block supporting the perimeter, but compacting the stone and machinery close to the wall, and no "dura wall" (ladder wire) makes me nervous with a block wall.
Maybe @ConCretin will jump in with his vast experience.

 

[ShawnHenrySpencer]

Block foundations have been gone for well over 20 years in my experience due to these concerns. You say 8 courses at the tall corner, 64" +/- . I'd think about backfilling the outside half of that height then adding your stone inside.
Has anyone mentioned to you "grade beams" or a poured or block series of posts out in the slabs "field"? You have your block supporting the perimeter, but compacting the stone and machinery close to the wall, and no "dura wall" (ladder wire) makes me nervous with a block wall.
Maybe @ConCretin will jump in with his vast experience.

Block is quite common here in East TN. Wall is doweled probably 8” into 2’ deep footers every 3 feet and poured solid all around to the top. The yard slopes, so backfill outside the slab on the lower end will still be quite minimal-maybe 2 feet up +/-. The pier heights will give you an idea of how much slope there is. My primary question really relates to whether the brick needs to be done now on the block or can wait until garage is completely framed.

 

[mike93lx]

Block is quite common here in East TN. Wall is doweled probably 8” into 2’ deep footers every 3 feet and poured solid all around to the top. The yard slopes, so backfill outside the slab on the lower end will still be quite minimal-maybe 2 feet up +/-. The pier heights will give you an idea of how much slope there is. My primary question really relates to whether the brick needs to be done now on the block or can wait until garage is completely framed.

Block is still common here in VA, too. I think it has to do with excavation depth and if a basement is being dug. Not many basements in these parts

 

[jack stand]

Block is quite common here in East TN. Wall is doweled probably 8” into 2’ deep footers every 3 feet and poured solid all around to the top. The yard slopes, so backfill outside the slab on the lower end will still be quite minimal-maybe 2 feet up +/-. The pier heights will give you an idea of how much slope there is. My primary question really relates to whether the brick needs to be done now on the block or can wait until garage is completely framed.

The brick won't really add any resistance to the outward pressure of filling and compacting the gravel.
Back in the block days they would partially backfill the outside dirt (in a full bsmt. condition) and once the weight of the mostly finished house was on the foundation, complete the backfill and grading. I know this doesn't apply to your garage.
Put your stone in carefully and with your slab resting on the block, I wouldn't run a compactor very close to the taller rear corner for the last 3 courses and keep watch on the outside mortar joints for any slight separation.
I do admire a pretty block foundation (like yours), my work was in "production" homes and large or national builders where block faded away over the past 20-30 years to poured walls.

 

[ShawnHenrySpencer]

Well, just to provide an update, backfilled as-is. Took 130 tons of #57. No issues. Prepped the slab with rebar and vapor barrier, and poured it Friday.

 

[mike93lx]

Well, just to provide an update, backfilled as-is. Took 130 tons of #57. No issues. Prepped the slab with rebar and vapor barrier, and poured it Friday.

How did you handle compaction as it was filled?

 

[ShawnHenrySpencer]

I didn’t backfill myself, but the guy loaded it in by bobcat and compacted about every 6-8 inches. Then, prep crew brought bobcat as well and smoothed and compacted once more and dug the thickened parts of the slab.

 

[Firebrick43]

I didn’t backfill myself, but the guy loaded it in by bobcat and compacted about every 6-8 inches. Then, prep crew brought bobcat as well and smoothed and compacted once more and dug the thickened parts of the slab.

By driving the bobcat on it or with a plate compactor?

 

[nmk_61802]

Glad it seems to be okay, but you probably haven't been around long enough to remember this thread:

28x40 garage wall falls who to blame???

I am having a 28x40 garage built so I can start a small fab shop to do projects out of to help offset my weak pay checks in the winter months. The general contractor is the husband to a coworker/ friend of my wife. He recommended a fella to do the foundation/block work for the garage this guy is...

www.garagejournal.com

I probably would have done as your friend suggested.

 

[mike93lx]

I didn’t backfill myself, but the guy loaded it in by bobcat and compacted about every 6-8 inches. Then, prep crew brought bobcat as well and smoothed and compacted once more and dug the thickened parts of the slab.

Hopefully it wasnt "compacted" with the bobcat.

 

[ShawnHenrySpencer]

Loaded with bobcat and plate compacted.

 

[mike93lx]

Loaded with bobcat and plate compacted.

Fantastic!

 

[ShawnHenrySpencer]

Glad it seems to be okay, but you probably haven't been around long enough to remember this thread:

28x40 garage wall falls who to blame???

I am having a 28x40 garage built so I can start a small fab shop to do projects out of to help offset my weak pay checks in the winter months. The general contractor is the husband to a coworker/ friend of my wife. He recommended a fella to do the foundation/block work for the garage this guy is...

www.garagejournal.com

I probably would have done as your friend suggested.

21 courses high? Should have poured all cells…not just the ones with steel. No wonder that blew out. I was worried enough to ask the questions, but 21 courses I wouldn’t have had to ask about. Mine was 8 courses max including the header block.