building a concrete slab to work on



building a concrete slab to work on

Postby grumpyvette » June 24th, 2011, 3:34 pm

working on a nice solid concrete slab is so much safer and nicer than on asphalt that I can,t imagine anyone not wanting to have at least a decent car port to work on their car, asphalt won,t safely allow floor jacks and mechanics creeper to function and working on dirt or grass or a couple sheets of plywood thrown over dirt or grass is almost unthinkable once youve worked on a smooth level concrete surface, "BEEN THERE DONE THAT"
unless there no other choice.
obviously if your planing to build a concrete slab you'll want to think thru your options and how much of the work your really able to do correctly, you sure don,t want costly mistakes or pissed off building inspectors or a defective or unusable slab,
contact the local building code department and check zoning laws and your deed restrictions and research what you can and can,t legally and financially do, ask questions and be darn sure to get everything in writing and have the local building inspectors happy with each step before moving to the next, check drainage, electrical and environmental departments before proceeding and fully understand that most contractors will do things the cheapest and easiest way possible, if the plans you draw up require a minimum of a certain diam. re-bar spaced every so many inches, you might want to do a bit of research, because in some cases slight upgrades, like moving to the next larger diam. re-bar or adding extra re-bar, or spacing the re-bal closer or in dual layers or specifying 3500psi-4000psi concrete vs 2400psi -3000psi some contractors will use if you don,t specify and verify what they use, adding extra re-bar will minimally impact cost but provide a significantly stronger slab but generally its not that difficult to have a local contractor form the footers and place the re-bar and even pour and smooth out a concrete slab. just be sure what your true future intentions are, a car port slab, won,t be acceptable too later turn into a garage floor or mount a two post lift on, most two post lifts require a minimum of 6"-8" thick and 3500psi concrete floor thickness ,things like that must be planed , and permitted for well in advance before the first shovels used

http://www.youtube.com/watch?v=9C62Hco9TeE

http://www.familyhandyman.com/DIY-Proje ... crete-slab

http://www.everything-about-concrete.co ... -slab.html

http://www.schlatter.org/House/pouring%20slab.htm

http://www.concretenetwork.com/concrete ... ulator.htm

http://www.buildeazy.com/newplans/eazyl ... _slab.html


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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: building a concrete slab to work on

Postby DeLong » June 27th, 2011, 8:28 pm

If you can't afford 3500 psi concrete wait until you can.It's the norm around here but 4000 psi is preferred. I'm not a fan of the cement bricks holding up the mesh. I won't let it happen on my pours.
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Re: building a concrete slab to work on

Postby grumpyvette » June 28th, 2011, 7:01 am

thats just a random picture off the internet, Ive usually seen the re-bar and screen held up with wire stand supports, similar to these

http://www.gamcoform.com/rebar.html
Image
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: building a concrete slab to work on

Postby DeLong » June 28th, 2011, 9:09 am

Those type of chairs are the correct way to build a slab. Great chart.
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Re: building a concrete slab to work on

Postby bob » June 28th, 2011, 12:33 pm

I remember when grumpy had his shop floor poured, he added several extra 30 foot or longer #5 re-bar runs along the foundation walls and had the floor poured extra thick, and he had the plans modified even before that point to have a good deal more re-bar in the footers than I regularly see.
plus about every 4 feet the columns from footer to tie-beam had re-bar and poured columns tied in.
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Re: building a concrete slab to work on

Postby grumpyvette » June 28th, 2011, 12:48 pm

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: building a concrete slab to work on

Postby grumpyvette » June 28th, 2011, 1:38 pm

"hey grumpyvette?I built my garage about 15 yrs ago and every time I have a lot of rain the floor gets wet. The guy who poured the pad dug down 2 feet, laid the hard fill but poured the pad level with my driveway. The driveway is on a slant and water runs in from the front and the sides. I have had a few suggestions from jacking the building up and putting it up on blocks then pouring a new 2 inch pad. Some also suggest digging around the whole thing, laying black perforated pipe and covering with stone. I figure some of you may have had similar problems. "

ID also point out that the slab needs to meet local building codes, and you need permits FIRST, and that usually requires both a minimum pad height and slope grade, (around here its 2 ft tall and a 5:1 slope) plus a footer needs to be formed and inspected and reinforcing bars placed , a footer is a thicker area around the circumference of the slab in my area it basically a trench with rebar that 2 ft deep x 2 ft wide around the edge with 3 pieces of rebar .
theres also grades of concrete, most common seems to be 2400psi rated you can pay a bit more per yard and get 4000 psi which is considerably stronger in my slab it cost an extra $12 a yard for the better concrete

http://forum.grumpysperformance.com/viewtopic.php?f=27&t=116&p=292#p292
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not that it helps in this case but its a great reminder for anyone planing a garage to have a pad built thats at least 24" taller than the surrounding area before pouring a garage floor pad, yes that usually requires a good deal of fill and having it firmly compacted to build the pad but its also going to mean a dry shop during hard rain storms, and in Florida where we get hurricanes thats MANDATORY if you want to keep the cars and tools dry as is selecting dade county approved doors designed to withstand 150 mph winds and sloping the area around the shop for decent drainage.
in most cases the soil will be tested to a depth of about 12 feet to insure the foundations solid if a pad is built to insure a stable base for the concrete pad., if its not the areas dough out and filled with a base of crushed rock and compressed dirt.
water runs to the lowest local area and pools after a hard rain, its your job to plan the shop site so its not located in the area water pools and to have decent drainage and a floor height thats high enough to avoid water intrusion under normal or even some rare conditions
, obviously you'll need to check building codes and your site plan but in most areas thats the MINIMUM mandatory pad height.
I had my shops pad built on a 48" tall pad with a 5:1 slope for drainage, again your deed restrictions and building codes will effect what you can do, but planing ahead always beats making corrections later


viewtopic.php?f=27&t=5035
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: building a concrete slab to work on

Postby grumpyvette » May 18th, 2012, 12:32 pm

one of my friends called me up today and wanted to know if he was getting a reasonable quote on a slab to be poured in front of his drive way, it measures 52 feet long and 12 feet wide, he was quoted $4900
I said thats insanely over priced, he wanted to know why?
so I said lets look at this, 52 x 12 is 624 square feet, you want the slab about 4" thick and youll need the edges a bit thicker , some re-bar and building permits
lets assume twice that 4" thickness , or 8" x 624 sq ft, to allow far more than required for the footers when calculating the concrete needed. a cubic yard of concrete will cost about $95-$120 delivered , so theres about 40 square feet of 8" thick concrete in a cubic yard of concrete.
624 sq feet divided by 40 sq feet= less than 16 cubic yards at 8" thick and about 8 cubic yards at 4" thick so you can figure about 12 cubic yards should be ball park on the concrete, thats about $1500 in concrete

http://www.cincinnatireadymix.com/concrete_prices.htm

lowes sells 10 ft long 5/8" rebar for about $7 each
http://www.lowes.com/pd_13095-157-34678 ... Id=3011756
youll need less than 40 so thats another $280

it would take less than a day for two guys to set up the forms, and more than likely they hire a couple illegal immigrants, or at least guys with limited skills as manual labor to do much of the hard manual labor at less than $10 an hour
permits are less than $300
so theres about $2K in materials the rest is labor, figure 3 -4 guys for two days at $22 an hour average or about $550-$750 more, add $500-$800in pure profit and your still WAY under the quote at less than $3000
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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