Pour the slab before backfilling?

[Erin]

I mean, I know that's the rule of thumb.  You really want the slab down before backfilling if possible, as it provides a brace at the base of your basement walls for a push-back against that new in-fill.

However, I also know that sometimes it doesn't happen that way.  The backfill needs to be done before the slab can be poured and people end up with a dirt floor for a while.  We have SBC block walls, btw, not poured walls.

So that's kind of where we're at. 
We have three big projects:  the roof needs to go on, the backfill needs to be done, the slab needs to be poured.   And the biggest hang-up is that I need the muscle of my husband for all three.  (Well, maybe not the roof, but he's fearless and I'm terrified of heights, so it's all his.  lol)   But, he works 6 weeks on, 2 weeks off in the oil field, so it's kind of a careful dance to be set up for big projects on his time home. 

We WANT the roof on ASAP.  Here on the central high plains, we'll get our first couple of snowfalls in October or November, but winter won't truly settle in until late December.  Ideally, we'd like to be covered before those first couple snows. 
But, to work on the roof, we'd be better off having the back fill done, because then our house is only 1.5 stories high instead of 2.5...
But, we're not ready to pour the slab...


So, what are some thoughts on this?

[Don_P]

It's best. You can brace it across the building and leave a slight gap in bracing coming from opposite sides as a telltale, if the gap ~1/16", becomes tight stop immediately and shift gears. It took my neighbor several years to pour the slab, I've also seen foundations fail.

[PaulB]

Hi Erin,
As an excavator I'll tell you I've done it both ways. The key to backfilling a wall without a slab, which is most common for a poured wall anyway, is to keep the machine away from the wall. Don't pound the soil in around the foundations and use a sandy, well draining backfill material. It will settle and the trench around the foundation will need to be filled in later but it does allow you to keep going. By all means though, pouring the floor will make the walls stronger. Also, keep the concrete trucks backed up toward the corner and not in the middle of the wall.
Good luck,
Paul B.

[Redoverfarm]

Generally I would like to get my roof covering and joist tieing the walls before backfilling. At least the subfloor w/floor joist.  If you do decide to put the roof on make sure you install gutters.  I have seen walls collaspe because of water from the roof on recent backfilled walls .  Don't get into a hurry.  Get your perimeter drains installed.  To lessen the chance of failure try to fill the walls with a medium sized stone ( # 57) for the majority and top off the last few feet in soil.  It will also allow better drainage than soil.

[Erin]

The perimeter drains are in.  The waterproofing membrane is up. 
And yes, we're going to use rock for much of the backfill.   (I was planning on pea gravel, though...  Stone is better?)
The joists and floors have been done for months.

My extension ladder is only good for about a story and a half, though.  It won't reach from the bottom of the excavated basement clear up to the roof!