Concrete handmixing versus pumping.

17 years ago

I got a bid from a contractor to add concrete to my crawlspace. He indicated he would use 5/8 minus gravel and pump in the concrete, when he did the bidding.

After we signed the contract he went into the space and now claims that pumping it in will not work because the pump guys will charge 150 extra per hour of extra length of hose and that that the extra

He said he can have his guys cart in buckets of concrete which sounds to me

a) very labor intensive

b) wont be consistent.

c) the concrete layer will be very thing as they might be tempted to take shortcut since it is appears to be so laborious

Its a 1500 sq foot crawlspace. How much concrete would he need- I shudder to think of how many buckets they are going to have to haul in.

Is this a red flag ? Should I insist on the initial agreement and ask him to get the pump and not do it manually. he also grumbled about the finishing time- saying he will need to hurry up with the finishing and it wont be so good if he hires a pump.

How much concrete would one need for a 1500 sq foot basement ? He has ordered 3 loads of gravel.

Comments (7)

homebound
17 years ago
Ok, I'm not a concrete guy, but this sounds like real b.s. I just went through an ordeal getting a concrete walkway & steps. But that's another story.

If he doesn't think there's time to finish pumped & mixed concrete, then where's he gonna get the time to do it after they spend all that time mixing, lugging bags, etc. Crazy logic, (but what do i know.)

Red flag, since he should have realized it when he looked at the job.
ani_t
Original Author
17 years ago
thanks, it does look a little suspicious, but he seems like a nice guy.
Do any of you pros have an opinion on how I should handle this ?
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bentruler
17 years ago
Did he say hand mix, or just hand place?
lazypup
17 years ago
To give you an estimate of how much concrete you begin by computing the total volume of the pour.

1500sq.ft.
A 3" slab would be 3"/12" = 4 or .25 feet thick.

1500sq.ft x .25 = 375cubic feet of concrete.

Concrete is sold by the cubic yard (3' x 3' x 3' = 27cu.ft/cu.yd)

375cu.ft / 27cu.ft = 13.8cubic yards.

The average mobile concrete mixer truck carries 8cu.yds
brickeyee
17 years ago
Before pump trucks became common lots of concrete was placed a wheelbarrow at a time.
The older masons I know could walk a full wheelbarrow along a bouncy 4x8 onto the scaffold and then into the forms or onto the floor.
As long as you get the thickness you specified let him go at it.
It just takes a crew of laborers.
woodinvirginia
17 years ago
Just had my 44' x 16' 4" concrete slab poured today with a side set of 11 steps & a landing. Which took 11 yds of concrete to pour. Now my space is open not a crawl. But I did rent pumper trucks to fill my concrete blocks when I had them poured. A pumper truck ran me $500 for a 4 hour min. in a ddition to my concrete truck.
In your application, I don't see doing it WITHOUT using a pumper truck. Like a guy said before he should have spec. this out BEFORE the contract was done. If he didn't that's his loss not yours. He has to eat the extra cost. No way I would stand for getting Labor to hand haul this mix in.. you will need around 25 yds and a lot of bodies versus working with technology just doesn't sound right.
reliabilityman
17 years ago
I would rather pump it that walk it. I have done both. Is there anyway they can rent one of those walk behind loaders. They work well for this.