Folks -
Today I spent most of the day doing honest work - shoveling dirt. I
cleared out 3 1/2 piles of dirt along the outside 24' wall - about 10-15
wheelbarrows per pile... We've got LOTS of dirt.... Anyway, I cleaned
things up around the trenches in preparation for bringing in materials for
building the forms and all. I called the Building Inspector today and axed
if he was available for some general and rebar-ish questions. He was more
than accommodating and came by in the afternoon. He immediately saw the
problem I had with "Deliverance Backhoe and Freakshow"... I explained the
problem with the variances in the trenches and he suggested a three-part
pour... which is what I was kinda wondering about anyway. He clarified
the questions I had about rebar placement and made a couple of other good
suggestions. I was up-front with him and tole him I may well ask him some
obvious, dumb-ass grade question... but that this was new territory... He
appreciated the candor...
Anyway, he suggested that I pour the footings alone, with a "key" channel in
the middle, then pour the stem walls on top of footings - bring in any
fill/sand/rock and make sure it's compacted well, then pour the slab.
Tonight, it makes sense.... I want to reduce the "pucker factor threat vs.
blowing the budget" factors to the best degree possible. The North wall
trench is only 12" wide... and ~22 deep... The South Trench is 24" wide and
up to 29" deep; the West trench is 19" wide and ~24" deep.... I haven't
finished clearing out the East trench that abuts the garage yet but I expect
it'll be at least 20" wide and 20" deep. Remember, I was shooting for 16"
wide, 18" below grade...
So, for the North trench footing I don't need any forms - it'll just be 12"
wide. The other 3 sides I'll set the forms 12" apart and set the height at
10" below grade all the way around. I have to have the stem wall a minimum
of 6" below grade, so with this I estimate that the 6" stem wall will be
14-16" tall to leave me 4" for the slab level with the garage.
I am going to put 2 runs all around the perimeter (120" total) of #4 rebar
on 3" dobies in the base of the footings, another in about the middle of the
stemwall, and one at the top that will be enclosed in the slab pour. I am
going to put vertical reinforcements in on 16" centers that will extend to
the bottom of the stem wall, come up and bend 90 degrees and be buried in
the slab. The inspector said that if they extended into the slab by about a
foot that that would do it.
I refigured my cost estimates based on this new configuration and all of the
materials come to $4,030, including about $700 for lumber for the forms that
I'll prolly use for a greenhouse. The cost of the concrete includes
delivery, so multiple deliveries won't screw me up cost wise...
Here's the quick cost summary:
W" H" Lineal Ft Ttl Yds Material Total Yds
Qty unit price ttl
12 12 48 1.78 Concrete for 2 24' Footings 1.78
100 191.11
18 12 36 2.00 Concrete for South Footing 2.00
100 215.00
12 18 36 2.00 Concrete for North Footing 2.00
100 215.00
6 18 120 3.33 Concrete for Stem Wall 3.33
100 358.33
W' L' Thick "
24 36 4 10.66 Concrete for Slab 10.66
100 1145.52
24 36 5 13.32 Sand 13.32
22 315.02
0.00 0.00 0.00
Total for Aggregates 2439.98
Foundation Materials
#4 1/2 Rebar 20' 33 2.65 94.01
5/8 - 10" Anchor Bolts 40 0.54 23.22
3x3 Dobies 90 0.55 53.21
16'x100' Tyvek
VB 1 30 32.25
Rebar Ties, 1000 1 10.69 11.49
2"x6"x20' for forms 40 15 645.00
Misc. Lumber & Supplies 1 100 107.50
Total Foundation Materials 966.68
Subcontractor/Equipment
Compactor (day) 2 days 60 64.50
Rebar Cutter/Bender 1 Week 95 102.13
Backhoe Svc 1 Each 425 456.88
Total Services 623.50
Total Materials & Services Estimate 4030.17
Sorry if the view doesn't quite make sense... I pasted from Excel... you can
get the drift of it tho'...
So, that's the view of things for today.
John