Concrete quote seems a bit high

[Racer X]

Starting to try to get things in motion for the 36x72 garage I want to build and got my first quote back. It seems rather high for what they are doing so wanted to run it by you guys and get some opinions...

They want to do a single pour of the entire thing, 4 inch thick with 12x12 inch beams around the perimeter. I specified a stem wall, but the quote doesn't say if it will be constructed of block or formed and poured as is common here.

Site prep consists of compacted sand under the slab. I think I would rather have something better for a slab this size, like maybe compacted crushed on top of the sand...

For this they want $9985. The concrete shouldn't run more than $4000, so $6000 for labor seems quite high. I have asked them for more detail and some clarifications, and am working on other quotes to compare them to.

Any thoughts?
Thanks!

 

[35mastr]

How much is the cement per yard??

 

[Racer X]

running about $90-100 per yard in this area...

 

[NitroPress]

A 2600 square foot single pour of 32-35 yards? I'm not super strong on foundation engineering but that seems excessive. Two or four finished pours sound more "right"...

 

[Racer X]

A 2600 square foot single pour of 32-35 yards? I'm not super strong on foundation engineering but that seems excessive. Two or four finished pours sound more "right"...

Yea, that was my feeling also and I questioned them about that. They seem to think they can get it done that way and that control cuts will be enough to handle any potential cracking issues.

Seems like they are just taking the easy way out though, which is one of the reasons this quote seems high to me.

 

[brownbagg]

I calculated 40 yds

 

[larry_g]

Does that figure also include the prep and materials to pour on? As my concrete guy explained to me that if there is a problem I would expect him to fix it at his expense, and I would. A lot of factors come into finished product and some of that as the weather and the mud as delivered. Either one can cause problems and you as the owner would expect him to fix it on his dime. So part of that 6k is insurance, part expenses, some materials, and hopefully some profit.

lg
no neat sig line

 

[sevensandeights]

Around here you can pretty much double the cost of concrete to get the total quote.

I also see things quoted as $3.50 - $4 / sq foot but that wouldn't include your foundation.

 

[Racer X]

Does that figure also include the prep and materials to pour on? As my concrete guy explained to me that if there is a problem I would expect him to fix it at his expense, and I would. A lot of factors come into finished product and some of that as the weather and the mud as delivered. Either one can cause problems and you as the owner would expect him to fix it on his dime. So part of that 6k is insurance, part expenses, some materials, and hopefully some profit.

lg
no neat sig line

It doesn't include prep materials... they wanted ME to source the sand, and were even asking if there was somewhere on the property that we could remove sand from. Again, seems a bit of a weak effort to me and is throwing some red flags. I have seen examples of their work and it looks OK, but I just don't feel like the effort of the work they are quoting matches the price.

 

[NitroPress]

I calculated 40 yds

34 x 70 feet at 4 inches = 29.4 yards
212 feet of 12x12 beams = 7.9 yards

37-1/2 yards or so. Right between our numbers, close enough.

Still a huge damned pour - too big, really. I wonder if this is a small-scale company overestimating their abilities, or a commercial-scale company trying to accommodate a small job?

 

[brihvac]

That would be about about $14-$17,000 around here. I am doing a 16'X26', footers on 3 sides (attached), 256 square driveway extension, 4" crushed stone and steel reinforcement under all concrete and all concrete is 6" deep. I am getting it for $6,200. Next cheapest price was $7,900 and it just went up from there

 

[Toolman12]

If this makes you feel uncomfortable then get 3 or 30 quotes and when you feel you have the one that feels right then thats the one. Added ten feet to the side of my driveway in the summer took 12 quotes and some patience but it got done and i still feel pretty good about it

 

[Racer X]

Just heard from them that price does not include the stem wall, so that is not making me feel any better about them!

Concerning the size of the pour, yes that has me uncomfortable as well. I told them at the start that I would prefer they did the beams/footers first, then do the slab in three sections. However they insisted that doing it all at once would be fine. I think that is just the lazy way out. Get in, get done, get paid.

 

[DMT]

Going rate here is $3-3.50/sf for a 4" thick slab depending on if you use wire mesh or rebar.

 

[35mastr]

Its not impossible to do it on a single pour. I have seen even bigger ones done all at once. I would prefer a single pour myself.

 

[Kevin54]

It doesn't seem too far out of line if they supplied EVERYTHING, but seeing that they aren't, I'd shop around for someone else to get what you want.

What you don't want id sourcing out to three of four places for fill, stemwall, trenching, and so on. You want a contractor who works with others and does it all start to finish.

 

[ConCretin]

Placing your slab in a single placement shouldn't be a problem at all for a qualified contractor with enough help. We place 10-15,000 sf floors all the time.

Make sure you talk to your contractor about vapor barrier, reinforcing and supports, saw cut control joints and curing. The answers you get will tell you a lot about the guy. Also let him know that you will expect the concrete to be placed at a reasonable slump.

With regard to price, place and finish shouldn't exceed .75/sf. is he providing a pump? that would add another $750. Depending on the pad and the other items I mentioned above, you could end up in the vicinity of $10,000 but it seems a bit high to me.

I'd get some more prices.

 

[pcmeiners]

Labor seems high for a single pour slab, was a foreman working on large slabs floors in buildings, a decent sized crew can easily handle it in a day, especially during cooler weather. If likely to freeze, specify they have insulating blankets, slab to be covered for 12 days minimum. Like you I would prefer crushed stone, specify the concrete psi load strength. As to reinforcement, unless you spec it, who knows what you will get. Don't forget to inform the concrete supplier and contractor the concrete will be tested.

"I specified a stem wall, but the quote doesn't say if it will be constructed of block or formed and poured as is common here."
If you don't specifically state exactly what you want. you will get what's easiest/profitable for the contractor's benefit in most instances. Personally I would want a separately poured footing/stem (even if frost is not an issue), your garage size will need the extra support.

As to compacting...again most contractors will not compact correctly unless you specify stone layer depth before compacting. Most contractors around here will fill 4 feet before compacting (useless), no less they will fill in over-dug areas with loose fill, without compacting the fill before the crushed stone. Specify the compactor being used... jumping jacks are a no-no on sand, not great on crushed stone, best is vibrating plate or vibrating roller

Compaction depth spec...
http://www.richmondutilities.com/media/infrastructure/vol3/dev02235.pdf
6" seem a bit overly cautious, 8" to 10" I think would be OK.

Really to be on the safe side, it would pay to get an Architect to draw up a very basic drawing, and spec up the pour according to good engineering practices, then hand out a copy to the contractors during the estimate process...hard to get screwed when a professional specs the details, and the specs become part of the contract.

$6000.00, if done correctly, I would be OK with... but dealing with contractor more then enough, it will not be done to good engineering practices without proper specs except by a very few contractors.

 

[jclem40c]

I just had a 28x36, 6" thick 3500# gp concrete with 18x18 haunch around
the entire thing and a 2 foot by 12 inch by 14 foot area under the 2 post lift
with a stem wall of 8 inch block all around except for a 36 in man door and a 12 foot overhead and all the site work (level, 6" of stone tamped and 4" insulation
placed, I had the insulation) for $6000. I would shop around a bit before I
went ahead with it. My $.02 worth.

John.

 

[racerbob4]

Get at least three bids from reputable contractos and check references. Also you definitely want a vapor barrier under the slab. We used re-bar in the slab instead of woven wire mesh. I think we have less change of cracking. Under the vapor barrier you should have crushed rock at least 4" thick.

 

[BillK]

Racer,
Personally, and especially for a job as large as yours, I would pay an engineer or archetect to draw up plans for the slab with all of the specifications the way you want tnem. Then the contractor does not have a choice. He will bid off your plans and specifications. That way you can get three bids for the same exact job and go from there. Also, with a specification sheet included in the contract, if they screw up you have something to fall back on.

Just wanted to say that if it was my garage, I would make it at least 5" and if you are going to have a lift, 6" in the area of the lift.

My 24x24 is 6" and has been bulletproof for almost 25 years. No cracks etc.

Just my opinion,

 

[TommyK]

+1

And do not make a decision based on price alone. People who know what they are doing and can demonstrate a 5-10 year history of happy customers deserve to be paid a reasonable price. If you do your homework and have clearly communicated expectations you will not get the cheapest price. You will get the correct price.

 

[brownbagg]

34 x 70 feet at 4 inches = 29.4 yards
212 feet of 12x12 beams = 7.9 yards

37-1/2 yards or so. Right between our numbers, close enough.

Still a huge damned pour - too big, really. I wonder if this is a small-scale company overestimating their abilities, or a commercial-scale company trying to accommodate a small job?

I read the post as 36 x 72 not 34 x 70

no footers?

 

[Racer X]

I read the post as 36 x 72 not 34 x 70

no footers?

It seems to be common here in Texas to do concrete pads with perimeter beams instead of footings. Frost isn't really a problem...

 

[Stargeezer]

Oh man...please don't forget to specify a ground rod/rebar ground pair in the poured footing. Especially if you have hard dirt and can't drive a ground stake easily.

 

[brownbagg]

It seems to be common here in Texas to do concrete pads with perimeter beams instead of footings. Frost isn't really a problem...

that what I thought, that the way we do them here, but I still came up with 40 yards

 

[TxPowderCoater]

Its not impossible to do it on a single pour. I have seen even bigger ones done all at once. I would prefer a single pour myself.

agreed , 40 yrds is a small pour, 4 trucks and kicker, blam done. monolithic is always better

 

[dlenkewich]

Guys on here from all over the world can't tell you what's good for your area.

Sounds like you're already having miscommunications with this Contractor with specifications and you're uncomfortable with his abilities. Throw this quote in the garbage and get three more.

 

[Nighttrain]

Racer X where are you located in Texas? I had my slab 2400 sf' in one pour. 2' beam around the sides and two beams across the middle. The back was raised a lot about 3-4'. They put in a lot of rebar and a vapor barrier. We had about 70 yards of sand brought in for fill. This was compacted. I forgot the yds of cement but it was a lot. $13k for the slab.

 

[Falcon67]

X2 - for a slab that big, you should be handing them engineered drawings and quoting from that, not off the cuff quotes. 12x12 perimeter sounds decent, beams every 12' OK, I'd want one down the middle too. Maybe 5~9$ sq/ft - hard to guess. 10K for one that size sounds "light".

A 2600 square foot single pour of 32-35 yards? I'm not super strong on foundation engineering but that seems excessive. Two or four finished pours sound more "right"...

The lanes on our drag strip were poured each in one shot - 25' x 800', about 740 yards per lane.

 

[Racer X]

Racer X where are you located in Texas? I had my slab 2400 sf' in one pour. 2' beam around the sides and two beams across the middle. The back was raised a lot about 3-4'. They put in a lot of rebar and a vapor barrier. We had about 70 yards of sand brought in for fill. This was compacted. I forgot the yds of cement but it was a lot. $13k for the slab.

I am just outside of San Antonio... your project sounds pretty close to mine as far as size. Also sounds like they put a bit more effort into it!!

I did give them specs to work from, and the fact that they didn't follow that and are trying to do it the way they want to is throwing major red flags. And the price still looks high for what they are talking about doing.

This is just one quote... I am working on others. This is just the first one I got back and thought it seemed a bit "off" so wanted to get some comments...

Good stuff so far guys! Thanks!

 

[geologist]

Seems a bit high (I'm in Ohio). I could see perhaps $7,500 - $8,000 here. No more than double the price of the concrete, ever, in my experience.

 

[NitroPress]

The lanes on our drag strip were poured each in one shot - 25' x 800', about 740 yards per lane.

Not by any means saying such pours can't be done - but from the pricing and rather naive-sounding comments, this sounds like a small-scale company trying to do something way past their limits.

I agree, this job needs a full set of blueprints before the first piece of rebar is cut. Just winging it is going to lead to trouble, one way or the other.

 

[brownbagg]

we poured a slab last monday 340 yds in one pour, took us four hours to get it down

 

[holdover]

Actually a 36 X 72 is a small pour for a commercial finisher, and here in SWVA no one would consider doing it in two pours unless there were special considerations. As to professional engineering, are you building on a swamp etc, if it is flat solid ground with good drainage why have the engineering done at the additional cost. Are you able to do the setup and have them just come in and do the pour.. Time equals labor if it is a turnkey job maybe the quote isn't too high, but I would get a few estimates. 35 yrs ago when I moved into this area and needed a cement contractor to do work for my construction company I went around looking for large projects such as churches and stores being built, talked with the cement contractors before and then looked at their work after they poured and finished, found a couple that did great work. I did not look in the phone directory for one, I wanted to see them on site and check out their work. If there is a good deal of excavation to be done that is another factor, when you total it up excavation, setup, fill, compaction, rebar/mesh, drains etc, and finish it adds up.. Get at least 3 quotes. If you can do the setup yourself, pour and finish is about .75 per foot +or - a bit, and the cost of the cement.

 

[camarotoolman]

Yes, pour it all at once, thats why its called a monolith. You want it all tied together. I don't see a problem for an experienced crew. I wound be concerned about how flat and smooth they can finish it.

 

[dtt454]

after having had some concrete done by a contractor who says one thing and does another, id rather pay more and not have to pay to have someone else fix it.

having said that, when i was getting bids it seems that materials was around 40-50% of the bids i got.

 

[cobrad]

I just finished building my garage addition, 22x25. Three pours, footer, foundation and slab. Not as big as yours Racer X, but I got 3 estimates and didn't go with the cheapest. I had drawings for each to bid from which made it easy to compare - apples to apples. If you have clay soil like a lot of Texas does, it would be worth your money to hire a soil engineer and a structural engineer. Because of the clay soil here in Colorado I over excavated under my foundation 3 feet and 3 feet under the slab. Imported structural fill. My Concrete bill was $7,800. Your bigger concrete contractors would be able to pour your slab in one day and eliminate the cold joint. I work for a major GC in Colorado and it's not uncommon to have pours to be over 300 cy or as high as 600cy in one day.

Brad

 

[camarotoolman]

You need to get a contract made up, so you and them understand what is to be done for $. I have never heard of 2-3 pours on a slab like yours? You're only are concerned about the finish, how flat and how smooth. Check some of there previous work. Before they pour, check forms for dips, humps and slope to doors. Both my house and garage were scrwed by those things. That size of pour shouldn't be a problem for a experienced crew.

 

[pcmeiners]

As to paying an Architect/Engineer...
For a very basic plan it will cost little. Professionals know the area, zoning laws, material prices, material specs, local labor costs, license, insurance and bonding needs. As I see it, is cheap assurance the job will get done correctly once the specs become part of the contract; if you spec it out yourself, you will be researching and thinking about it for days, miss details, and possibly over-pay for the job.