Who has poured their own garage floor before?

[ruf-porsche]

Originally posted by chrisp
I had a guy come this morning to quote. I think you are all right to get a pro to come do it. Like anything else, there's no option to redo it (without big money being spent) once I am half way through.

The code is supposedly four 12" footings on the corners, a 42" frost wall and 6-8" above grade. I don't know the thickness of the slab he is quoting yet but I'll make sure he doesn't short change me on the thickness.

Thanks for all of the input and help. Glad to hear you can pour or place it.

The footing should be continuous underneath your foundation (frost) wall, and not just at the four corners. If you just have the footing at the four corners, than you made the frost wall into a transfer beam that is transfer the weight of your garage onto the four footings, instead of spreading the load.

Are you building a frame structure or masonry structure?

[widebody911]

How timely - I'm in the middle of this myself!

[MotoSook]

Thom, how long did it take the neighborhood kids to dig them trenches? Or was it the cheerleaders that did that

Looking good...

[juanbenae]

those appear to have been dug by hand, maybe a chipping gun with a spade bit? brave man to undertake that task, be it digging it yourself or puruzzing the hood for some day laborers. my hands got blisters just scrolling through the pictures.

[widebody911]

We ran a ditch-witch thru it Saturday, which gave me a 6"-8" 'starter' trench. In the 2nd picture, you can see the trench for the electrical - that's about what I started with. I excavated the rest by hand Monday afternoon. Took about 5 hours and 6 bottles of Gatorade.

[chrisp]

No threat of frost in CA makes this a much easier job huh?

[widebody911]

Originally posted by chrisp
No threat of frost in CA makes this a much easier job huh?

Frost? Wasn't he a poet or something?

[Superman]

Though I've never worked as a cement mason, I have been dealing in the construction industry for a while and I can report there is some mythology in the posts above. Glossing past that, I'll offer just a couple of suggestions. Expansion joints - yes. reinforcing - yes. Go ahead and mess around with wire and fiberglas, but also take my advice and use some STEEL. Rebar sticks are very cheap. Use them. Use many.

Concrete does not dry. It cures. You can wet it until you're blue in the face and it will still cure. It will cure under water. I recommend you stay away from hot mixes, unless you are building a runway and the planes are getting ready to land. Slower curing is better.

The compression strength of the concrete will be determined by the aggregate used. Use good rock and you get good concrete.

And finally, go ahead and prepare the site yourself. Have a carpenter check it before pour-day (like the 30-year veteran above, I and the rest of the construction industry seems to be unaware that you don't 'pour' concrete....they all think that's what they're doing....even the engineers). When it comes time to pour, hire a crew that knows what they're doing. Or at least, hire a crew that contains at least one person who knows what they are doing and brings tools.

Oh, and thickness is often less important than people think. Be sure you create a good, dense, packed, non-organic (use rock or sand, not dirt) sub base. If you do this, two inches is enough. I mean, two inches is enough thickness for a concrete garage floor (two inches is not enough for certain other things). wink.

[KTL]

The reason wire and fiber mesh is used for flatwork is ease of use in PLACING (pour, place, dump, who cares? enough with the semantics already guys!) the concrete. When you get crazy with too many bars, it's hard to place a nice dense monolithic slab with all those bars, ties and stirrups in the way. Then you end up using a vibratory unit to shake down the mix. Too much vibration? Brings all the moisture to the surface and sends most of the aggregate to the bottom. You then end up with a non-uniform concrete mixture.

Don't forget to tell our friends where to place the bars. The bars should be in the lower section of the slab (beneath the centerline of the cross-section). Why? Because this is where the slab is in tension when loaded. Concrete's strength is in compression. Not tension. Hence the use of the bars. Compression strength is determined by the combined work of all the components of the slab. Certainly bad aggregate is going to hurt your strength.

Sure concrete cures under water. Not a recommended method. Water-cement ratio is a very important parts of the concrete recipe. Too much water spoils the stew. Just try to keep it moist. Here is where a semi-wet mixture is good. And, as was said before, a stiff mix is a PITA to place and finish anyway...... Let's be reasonable here. This is a garage floor for a home. Not industrial use. I'm all for overkill but you gotta make concessions sometimes.

For flatwork, more often than not, the 2 in. base cushion (the subbase is the material beneath the base- usually clay around here) is for levelling purposes. Leveling gets you that uniform, monolithic slab I mentioned before. 2 in. of crushed stone gets you little strength. Sand even less so.

[rs911t]

Poured the contents of my oil tank on the floor. That count?

[thabaer]

Originally posted by avi8torny
You don't pour concrete.....you place it.

If I can be poured out of a booth backwards after too much sake, I'd say just about anything can be poured

They make us go down 48" around here for frost heave.

[juanbenae]

may i pump concrete if the distance is too far to wheelbarrow or is there some queens propper that i should use for that?

to bad this was not an amish horse and buggy BBS, you would have all the skilled help you need!

[Rouxzy]

When you guys are talking about water content in concrete than you are talking about the "slump". A descent slump is 7 but a better quality concrete is 3 to 5. You can also order 2000 pound concrete or 10,000 pound concrete. Is it harder to work with? Oh yeah. But you lay concrete in one day and use it for many many years. I've workded jobs where we were placing concrete to the tune of 60+ trucks in one shift. It's hard work and if you are not sure what you are doing all the hard work will be for not. My advice is do what you're doing. Get a couple of estimates from reputable contractors and tell them exactly what you want it for. I also advise get as much knowledge as you can so you can ask the right questions.
Tom

[Rob McKibbon]

Chris,
Best idea is to sub it out..... good choice.
I have placed and finished concrete many years ago.
I R a construction engineer and I call dirt, soil; and I never say "pour" concrete.... ya right?

I am now a developer/ builder and I've built over $100 Million worth of $2 - 3 Million buildings over the last 10 years. The problem with concrete is that it gets hard, then it's harder to remove than anything you'll experience, even 911 heat exchangers. (Had to put Porsche in some where?)

My estimate for your job:

Excavate, backfill and compaction $500
Find a backhoe guy with a compacter. Do not place footings on topsoil or loam, twigs or anything that can rot. Place footings only on good "undisturbed" soil. Hand excavate the last 2 inches for best results and check soil by puching with a 1/2" bar. If the bar goes in too easy, remove soil until firm. Spread footings (continuous) are the most forgiving as they "spread" the load.
Includes 6" layer of 3/4" minus gravel (road crush) compacted under slab on grade.

Forming Foundation Walls $1500
Includes pouring strip footing approx. 16" wide X 6" deep continuous with 2 continuous strips of 15M reinforcing steel (rebar). Then forming a foundation wall on top of strip footing 8" wide X 36" high (depending on frost depth for your area). Included are forms, wall-ties, and placing of concrete.
Not included is concrete and rebar

Reinforcing Steel (Rebar) $300 Supply only
Place 2 - 15M bars running continuous side by side in the strip footing. (Lap and tie the rebar together, same for walls)
Place 3 - 15M bars running continuous in the foundation wall, one near the bottom, one just below mid-way height and one just above mid-way height. This can be tied to the form ties.
Slab: Place 10M rebar at 1ft centers tied together with rebar wire.
Put "chairs" under the rebar to hold it up off the ground.

Slab Prep, Place and Finish $300 Labour only
Prep slab by placing vapour barrier over compacted gravel sub-base. Tie and chair up rebar for slab. Place and finish concrete slab on grade with hardener compound. Spray sealer.

Saw cut control joints $150
Saw cut concrete slab the day after it is poured approx. 1/2" deep 10 foot centers for controlling cracking.

Concrete Supply $1800
Strip footing, Foundation wall, Slab on grade
Used for estimating purposes: 18 cu yds (14 cu m)

Misc. Items $200
Supply of Hardener, Sealer, Vapour Barrier, Impregnated Asphalt Board (for edge of slab, to break bond with foundation), nails, band-aids.

Beer $100 Average Day // Beer $300 Hot Day

Air-fare, Accomodations and Fee $8,500
Self explainatary?

Quote valid for 15 days...... bla bla bla

The majority of the costs are for materials and you'll only save a few hundred bucks doing it yourself; there are so many things that can go wrong..... so sub it out to a pro. Unlike Porsche mechanics, construction workers are cheap - find a Portuguese guy named "Tony" for best results.

Hope this gives you an idea of what to look for in an estimate? (off the top of my head) If you have any questions feel free to PM me as we're likely to go OT on this? I'm always glad to help out where I can?

[Rob McKibbon]

Originally posted by k911sc
may i pump concrete if the distance is too far to wheelbarrow

Yes..... concrete pump will run you about $300 for a couple hours.

Most can reach about 75 feet, some 150ft. Best to find a concrete supplier that will give you a quote to Supply, Pump and Place the concrete (IMO) then you have one price per cubic yard and not a concrete truck (late as usual), and hourly pumper truck and hourly labor to place???

Also, if they do a lousy job "placing" or "supplying" the concrete, you have more clout with a larger company making good. >>>> Honeycomb in concrete is one example of poor placing.

[chrisp]

This only gets better. I even ended up with a quote. Yes likely to go OT but in the meantime it's great reading.

[stew]

out here it's about 300.00 a yard installed. hire the pro. i build houses and still hire the pros. poured the basment slab for my latest house 30x34 slab complete with pump 2500.00