building a concrete slab to work on



Did you see where HELL -liary said if elected she would appoint the muslim to the Supreme Court
They got me booted off of Digital Corvette for daying Pontiac and Hellcats the group that hates me. They PM each.other and in bed with the Mods there.
DC only good for Newsroom. Zero Drag Race action which I hate.
Its rhe End Of Times Ralph.


"One test is worth a thousand expert opinions."
Damn, you and I think alike. Each slab is a monolithic pour. The 100 foot wall has a concrete footing.
9 ft high in back of the shed. About 900 blocks took me 8 years to lay. Each is pinned and glued. About
200 tons of stone behind the wall for drainage. Slotted drain pipe at base going out to the street and
another pipe closer to the surface. All slabs are overbuilt. 6" of concrete with 12" stone underneath.
Reinforcing wire and re-bar tying everything together where possible. The hill used to end right behind
the garage. It's all ledge underneath. 2 years of jack hammering before I had to call in the big equipment.
All digging for slabs around the garage done by myself with a shovel.
The 1 car garage will be coming down hopefully soon and will become a 2 car with a workshop at the rear.
When that happens, the entire slab except for 42" from the wall, will be over-poured with another 2 inches
of concrete, but I have to find out about incorporating at least a 2 foot wall at the edges because I don't want
the grass right at the bottom like it is now. This year I plan to have the digging done and stone placed for
extending the driveway in front of the slab and running a drain pipe to the street.
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The Grumpy Grease Monkey mechanical engineer.
Staff member
wow, great detailed pictures

BTW heres three calculators (Id add 10% )

take the time and effort too read through these links it can save you thousands of dollars

remember the footers surrounding the concrete floor slab will be about 2 ft deep x 2 feet wide
and the slab will need to be about 8 inches thick where the lift is mounted
youll need a certain amount of rebar in the footers and slab



(BTW the number is the number of 1/8" in diameter the rebar measures)
so a number 5 rebar is 5/8 diameter
if a building code calls for lets say #5 size rebar you can and probably should tell your builder to step up the size at least one or possibly two larger steps
(thats what I did, it only added a couple hundred dollars to the cost of the shops construction but significantly increased the slab rigidity potential.
and concrete quality varys if you don't specify the strength you get the minimum, which is generally the 3000 psi version, you can upgrade to the 4500 psi version for only about $15 a cubic yard (again what I did)


verify local building codes
and remember the slab and footers will need to be elevated above the surrounding areas height,
for decent drainage (usually 3-4 ft.) minimum
and the area sloped out at a minimum 5:1 ratio,
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Be nice when the garage walls go up Loves 302.
Good days ahead.


solid fixture here in the forum
Staff member
Please don't take this the wrong way but why is this project so over the top? It's great looking, clean work. Looks like you could be building on the perma-frost in Alaska LOL! Are you a masonry contractor?


The Grumpy Grease Monkey mechanical engineer.
Staff member
Im always rather amazed , at how contractors just assume that most people are totally clueless and will blindly accept any estimate they get shoved under their nose to sign.
one of my sons needed a 20 ft wide and 40 ft long section of concrete about 6" thick and a 30 ft long section of 24" culvert for drainage in his drive way
he was quoted $7K by the first contractor
now 20 x 40=800 sq feet, or 89 sq yards, 44.5 sq yards 1 foot thick , or roughly 16 cubic yards of concrete, the current cost of concrete is well under $150 a cubic yard
now lets assume he needed 20 cubic yards with the footer deep er edges, 20 x $150-$3000, the culvert costs under $500 for a 20 ft section, lets say he requires two sections
so were still up to $4000, throw in $400 in rebar, and that leaves $2600 labor.. figure two days max thats still over $120 an hour
I told him to get at least three more estimates
yeah there will likey be two guys but all those prices are estimates on the higher end of what ID expect too see.
Id bet the job gets done correctly for under $5000, maybe a lot under

Strictly Attitude

solid fixture here in the forum
Ok this is underground is the contractor needing a machine on site to dig? Is the Colvert dug out yet. Crusher run and compaction also. Just a few things you forgot.


The Grumpy Grease Monkey mechanical engineer.
Staff member
the ditch for the culvert exists, and is in the correct location and at the acceptable depth
I wish I was closer , I have a tractor and I installed the culvert to building code specs in my driveway,
and graded the drive way, here in florida, now I have a gravel driveway,
but being very familiar with building a slab, having done three now,
I still think hes being quoted on the high end,obviously I'm not there,
and don,t have all the facts ,but looking at the pictures he sent ,
and having looked over the diagram's and permits he pulled,
it seems rather less complicated.

Strictly Attitude

solid fixture here in the forum
$2000 to pay 4 guys 2 days of labor at $30 an hour, setting forms, crusher run delivered compacted rebar set. Pouring next day trowel for drainage need concrete slump correct or will level. Clean tools and wheel barrel. Brush finish concrete then cover to keep moisture in wet burlap depending the temps usually not done but can weaken concrete significantly as I am sure you remember from materials being an engineer. My DOT experiance coming out required for most of our jobs. Come remove all forms next day clean forms for next job 6" may also need make wood forms. And don't forget form release also. Not complicated but this is from my experience doing it for a living for over 3 yrs. I am not saying high priced or low but contractors are making bank cause lack of working trades men out there.

Strictly Attitude

solid fixture here in the forum
I rounded the 4 guys 2 days work 3 not full days of work averaged to 2 and 30 being average labor including contractor to be fair.


The Grumpy Grease Monkey mechanical engineer.
Staff member
I don,t think I will have much realistic input as Im many hundreds of miles distant
but I think that first $7K quote was vastly excessive, and mostly based on the fact ,the contractor,
figures if you accept the bid you have more cash than brains and he makes good money,
if you don,t accept... he looses nothing or can come back with a more reasonable offer

Strictly Attitude

solid fixture here in the forum
I also feel if you were there that you could avoid using the contractor all together even if just guiding your son through the job.


The Grumpy Grease Monkey mechanical engineer.
Staff member
I was recently asked
how long you generally wait for the slab concrete to cure/harden,
before you start laying concrete block walls or drilling the slab for expansion bolt anchors,
for a metal building like many guys build?
now temperature and the concrete mix ratio and weather all effect drying times on concrete.
every contractor I talked with suggested 3500 psi concrete as absolute minimum,
and paying a bit more for 4500 psi concrete was a very VERY good idea,
every one suggested lightly misting the concrete with water every few hours for the first 4-5 days,
and not starting serious construction on the slab for a MINIMUM OF 7 days
your contractor is likely to want to wait only 2-3 days, don,t go that route

hilti fasteners' said:
Dear Customer,

thank you for reaching out to us. In view of the significantly lower strength of green concrete
(less than 28-day cure),
it is recommended fastenings with Mechanicall and adhesive

anchors not be made in cast-in-place concrete which has cured for less than 7 days,

unless site testing is performed to verify the fastening capacity.
Anchor fastening capacity should be based on the concrete strength at the time of installation.
Adhesive anchor design should be based saturated concrete.
Don't hesitate to contact us if there is anything else we can do for you.
concrete will not reach its full hardness for well over a couple months time,
but it should be strong enough for more construction to be done after a weeks time,
be sure to round UP your order a couple cubic yards and specify 4500 psi concrete
,you certainly don,t want to come up a yard or two short and have the slab,
made thinner as a result
and ID strongly suggest 8" minimum slab thickness.

The continual hardening occurs because cement particles react with the water in the mix (hydration), and as long as cement is in contact with moisture, even miniscule bubbles, it will continue to form bonds. This is minimal after “full strength” is achieved, but it is continual.

In standard industrial cases, full strength concrete is recognized at 28 days. At seven days, you should have concrete that is cured to 70% full strength or greater. But to answer the question of, “How long does concrete take to set?” concrete setting time is generally 24 to 48 hours. At this point the neighborhood dog will not leave his footprints in it, but you should keep it clear of heavy equipment during this time period. Most mixes are cured at 28 days.

  • Waters-Effect-on-Cement-2-238x300.png
    Moisture plays a critical role in curing time for concrete. If there is not sufficient water in the mix, the concrete will cure too fast, resulting in weaker overall strength. Too much moisture, often used in the finishing step will weaken the top layer and cause flaking.
  • Hot ambient temperatures and wind accelerate the evaporation of moisture–speeding concrete setting time.
  • The mix design has a lot to do with concrete setting time. Some jobs will require accelerants because the area needs to be usable as soon as possible. The accelerant will do its job and speed up the concrete setting time. Accelerant mixes will show a weaker overall strength in the end, but will still meet strength requirements.
Temperature also has an impact on concrete setting time. For more information, check out this article about how concrete curing temperature makes a difference.

I was rather shocked but not really surprised at this video of horrible sub standard work on a concrete pad
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