[TowerTalk] Tower Foundation (was Concrete Prices)

[Jim Lux]

On 1/2/14 9:05 AM, Marsh Stewart wrote:
> I live in NW Louisiana. I'm looking for a concrete contractor to install a
> base per specs for a US Tower HDX-555. I need a hole 5' X 5' 7.25', rebar,
> about 7 cubic yards of concrete, and 3 anchor bolts in the right place. I
> have the anchor bolts and base. (If the layout of my lot, house, and pool
> would allow it, I'd put up 60' of Rohn 45G, with 2 sets of guy wires.)
>
> A major consideration is that access to my backyard is 42.5" wide through a
> walk gate and between an A/C compressor and a brick wall. If the A/C
> compressor were temporally removed the width of access would increase 4" to
> 46.5" - not wide enough I'm told for even the smallest of back hoes.
> Removing a section of fence for better access is not an option.

Yeah, and moving/removing the air conditioner compressor/condenser is a 
very non-trivial operation, since you have to pump out the refrigerant, 
cap it, then put the refrigerant back in, etc.

Several hours work at probably $100/hr when all is said and done.


Your basic Bobcat is about 5 ft wide.. However, because it's fun to go 
through the Bobcat catalog.. you COULD potentially find a Bobcat 
MiniTrackLoader with the Backhoe attachment.  The Mini TrackLoader is 
only 3 feet wide.

http://www.bobcat.com/attachments/backhoe

http://www.bobcat.com/loaders/models/minitrackloader/mt55

Yeah, it says it's compatible, BUT.. that's a pretty small base for a 
big ol' arm hanging out there.  It might exciting to operate.







>
> Almost surely the hole will have to be dug by hand and the excavated dirt
> moved by wheelbarrow to the front yard to be scoped up by a front-end
> loader.

I don't know how flat your area is, but around here, where everyone is 
on a hill, you get a low boy dump bin, set it on the downhill side with 
a ramp, and run the wheel barrow across the ramp and dump.  Not much 
"uphill pushing".

BTW, if you're going to move a lot of heavy stuff, getting a two wheel 
barrow is worth it.  Rather than one small wheel in the front, and 
having the operator lift most of the weight, it has a big wheel on each 
side, and virtually all the weight is on the axle.



>
> Bid #1: $6,880 - contractor never showed up. The one time I did run him down
> to check with him he wanted to change the specs to a 6' X 6' X 6' hole.
> Right or wrong, I'm going to go by US Tower's specs.

8 yd of concrete vs a bit more than 7, and realistically, it's not like 
your hole will be 5.000 feet across and 7.5000 feet deep.  "backhoe 
accuracy" is on the order of 4-6" unless you've got a really skilled 
operator who's motivated  (e.g. digging next to something critical). 
His quote/thoughts are probably based on the width of his bucket, and 
experience.  A lot also depends on the soil. Making a perfectly vertical 
wall with perfectly right angle corners is tricky (and unnecessary in 
most cases).  His hole might be no bigger than 6x6 at the top (you give 
him some painted or marked lines to work within) and get a bit smaller 
at the bottom.

I'd figure on digging a hole that's a bit bigger than 5x5 feet and a bit 
more than 7 1/2 feet deep.  You can trade off machine operator time for 
precise measurements against extra cost for more concrete to fill the 
overage.

There might be a good reason he doesn't want to go deeper than 6 feet 
(tougher to square up the corners? local knowledge about the water table?)



>
> Bid #2: $9,000



>
> Do those prices sound reasonable? They sounds high to me, but I have no
> reference as to what concrete work should cost.
>

Is the contractor fabricating the rebar cage too?

Around here (THousand Oaks, CA), a backhoe rents for about $400 day plus 
$100 delivery charge, and this is less than a 1 day job.  Figure 
$30-40/hr for the operator for 4-6 hours, and you're looking at another 
couple or three hundred bucks.

However, since you can't get a backhoe in, you're looking at hand 
excavation, and more than waist deep, which means that he has to deal 
with shoring and that sort of thing.  The actual digging labor is fairly 
inexpensive $20/hr or so, but you'll need a few people, but the shoring 
as you go down is tricky and takes equipment and time, which has to be 
ferried through your narrow passageway. That takes time and money

Figure a day to build the rebar cage

A day to get the cage in the hole and the concrete poured and finished.

There's a day of work spread around to do stuff like put up plastic and 
plywood to keep from damaging the side of the house and the grass and 
stuff.  And to take it down and clean up afterwards.  There might be a 
cost to take junk (concrete cleanout) to the dump too. Or to haul the 
dirt away.

Probably 3 or 4 days with a couple workers at $200/day/worker, so 
somewhere around $1500-2000 in labor.  Then he has to pay himself, and 
insurance, and so forth.

8 yd of concrete at 150/yd is $1200, and another few hundred for the 
pumper truck (or guys to wheelbarrow it)

It's clearly not a $3000 job (at least around here), but it doesn't seem 
like a $7000 job either, but it could easily creep up there.

Your quote might be high because it's work he really doesn't want to do 
the work, or he's aiming a bit high so he is sure to come in under 
budget, or because he anticipates unexpected difficulties.



> 73,
> Marsh, KA5M
>
> ------------------------------------------------------------------
> On 12/24/2013 9:29 AM, Mike Reublin NF4L wrote:
>
> I want to see if I can get a reasonability check on the price to
> pour the base for my HG-70HD. 4x4x7 1/2 feet. I'm getting the base
> from HG.
>
>
> Bid #1. Did hole by hand, bring concrete from street with a power
> wagon. 3000# mix. $1500.00.
>
> Bid #2. Dig hole with "trencher". pump concrete from street, 3000#
> mix with fibers. $2500.00.
>
> 73 & Merry Christmas,
> Mike NF4L
>
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