Concrete Questions for Garage Construction.....

All, I am working on adding two garages on my property. The larger is a 24X32 and the smaller one is 14X20. My father was in construction and I have done about everything in-home construction, except, major concrete. I have done sidewalks, patios, etc but nothing major. This is where my questions originate.
I have read a few books and gotten my permits. I marked out the location of the new garages and squared them up over last week after work. Then last weekend, I broke ground with an excavator and a large bobcat. Knowing that I would be better off (concrete savings) having a professional dig the actual footer, I hired a friend of a friend to dig my footer and I operated the bobcat. Things went as expected and my figures for stone and supplies came out. I am preparing for inspection and this morning I cleared out the roots from a few trees that sit in the back 30 feet of my property. I am planning on pouring the footer then the finished slab.
The one thing that I am concerned about is during the excavation we ran into two leach fields (at 3 feet down), an old septic leach bed and a leach bed from an old gray water system (at 2 feet down). I am positive that these systems are both no longer used and the main tanks are filled with sand. I know this for certain because I did this and the new sewer line to the house (120 feet)with my dad when the city sewer came to our area about 10 years ago. The septic system was original with the house (50 years old) and was about 200 gallons (very very small) and the leach field was only 120 feet in a Y. The gray water system ran the washing machine and dishwasher only and was 110 gallons and had only a 45 feet leach system but had a very large diameter.
How is something like this normally handled?
I have, so far, crushed and removed them from the footer entirely and have filled them with foam and packed the ends with dirt and stone tightly. There was no water in either system as expected.
Are these pipes even a concern at this point?
My next question is concerning the next steps in the concrete process.
My plans, and please correct me if I am wrong, is the following;
1) I will get approval from the city that my footer and stone etc is good. I assume they are mostly concerned with depth, width, and straightness of the footer and the stone is 4 inch or better. 2) I will rebar the footer 3) I will bring in the concrete and pour the footer to the bottom of the stone. (stone started 4 inches below earth grade) 4) I will then place my forms (2X8s) and make sure everything is of correct size and square up the forms. 5) I will place my 6X6 10 Gauge wire mesh to the footer 6) I will then have the concrete brought in and will pour and level out with a Bull float/screeds/maybe even a power trowel. 7) I will then place the garage bolts for the sill board 8) Spray on curing agent
Now, I am considering having the above done after I get approval from the city inspection. As I have a friend who has a friend that does this for a living. I have seen his work and I think it looks decent. So everyone knows, this is very against my grain as I hire very few things out. My main concern is the man power behind this and the skill to do the final level/finish but I know getting to this point is a very big step.
Now what should I expect to pay outside the cost of materials to have him do this? What is the norm? I have been told he will bring in 4 guys at $250 a day for the actual pour. What should form, rebar and mesh placement cost me?
I have another option to finish this concrete which is decent as well. I personally have a long time friend that is in the heavy machine operating trade (40 + years) and has done a lot of large scale concrete/masonry in his life. I have seen his work and it is decent.
Any opinions or suggestions?
Sorry for the rambling.
Thanks, Chris Solomon_Man
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All, The tile for the leach field for the septic system is a orange ceramic - 3 or 4inch (very small) and the gray water system is a 8 inch pipe that is coming up to the front right corner of the garage. I was able to use a knife and cut the 8 inch pipe, with a pocket knife, one foot back completely away from the garage and its footer. The pipe is a thin black pipe very flexible with what seems to be clothe surrounding it. The 8 inch pipe was also at the end of its run and lucky for me ran till its end in my footer which of course I completely removed. The 8 inch pipe is not under the garage nor is it, at least in my opinion, a in the way problem. If the 8 inch is a problem I would prefer to remove it after the footer is poured as it goes back I am guessing 20 or so feet to the tank to avoid screwing up my footer walls and using excess concrete. The ceramic pipe is 3 feet down and my area soil is thick dark clay. The ceramic is somewhat of a concern but to remove it would require a complete diagonal cut across my 24X32 garage at three foot. Before I would consider digging it up, I would look at options of filling it with solid concrete as it would only be a additional 1/2 yard (max) according to my figures.
Just some more information.
Thanks, Chris Solomon_Man
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If the old lines crossed the footing, no big deal. If they ran the same way as the footing, you need to worry about compaction and dig down to undisturbed soil. An 8 inch pipe you can cut with a knife sounds huge for gray water, sounds more like an area drain. Deal with it after you stabilize the area.
My plans, and please correct me if I am wrong, is the following;
1) I will get approval from the city that my footer and stone etc is good. I assume they are mostly concerned with depth, width, and straightness of the footer and the stone is 4 inch or better.
What stone? Yes, they will be looking for frost depth. Footing inspection here would expect the steel in location, tied, supported, proper distance from dirt, correct laps, and corner bars. They really don't care if it is straight or over wide - those are things you need.
2) I will rebar the footer
See above. Code here demands 2 #5 continuous, lapped 32 bar diameters where necessary, corner bars tied in.
3) I will bring in the concrete and pour the footer to the bottom of the stone. (stone started 4 inches below earth grade)
The inspector may demand that reinforcing steel tie the slab to the footing, I would J bolts should extend into the reinforced footing zone. I guess you are talking about a gravel sub base under the slab. You will want finish floor well above the surrounding grade. Code wants 6" of fall in the first 10 feet away from the building as a minimum. So do you. You've not said what the garage was to be made of other than planning on a wood sill plate. Brick/siding/wood frame It would be best to have sheathing and/or siding to lap below the slab edge to seal the weather away. You will need at least 6" of concrete exposed below the siding for termites and rot, and then the six inches of fall. Many guys plan to form and pour the footing and slab at the same time. It is also fine to pour a footing and then form a stem wall or slab on top of the footing. The forms need to extend at least to the top of the slab, or extend a stem wall above the floor level to help with grade issues. It can be difficult to edge form at the outside of the footing as you cannot drive stakes, thus why many guys pour monolithic.
4) I will then place my forms (2X8s) and make sure everything is of correct size and square up the forms.
If the 2x8 is an edge form, it is marginal at best, though this is subject to footing height. How are you planning to hold and brace the 2x8's? I hope you have batter boards up for the footing excavation already, they should be set to line and grade.
5) I will place my 6X6 10 Gauge wire mesh to the footer
Remesh should be set on blocks before the pour. It has little or no value at the footing. It does nothing to strengthen the concrete, it is there to reduce crack separation. I would prefer not using it were it mine. Spend the time/money/effort on well compacted subgrade. If you parking tractors or buses, increase the depth of concrete and consider rebar reinforcement. You've not ever indicated what depth of concrete you intend.
6) I will then have the concrete brought in and will pour and level out with a Bull float/screeds/maybe even a power trowel.
It is just a semantics problem. You set screeds to be able to "rod" the concrete. Once you have rodded the concrete to grade, you use a bull float to flatten, bring cream to the top, and fill and densify small holes. This is too much concrete for one man with limited experience. Make sure the bleed water comes off before you begin any type of finishing. Knee boards, hand float, and 2 trips with a hard trowel or power float and power trowel. If you have not ever used one, find someone who has.
7) I will then place the garage bolts for the sill board
Set all J bolts in templates nailed to the forms. Do your go-zintas before the pour. They need to go into pretty wet concrete, you might as well get em set beforehand.
8) Spray on curing agent
Are you casting recessed pockets for the overhead door(s). Level floor rather than pitched to drain or door? Are you casting a brick or sheathing pocket around the perimeter? If so, make sure to omit at doors and openings.
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All, The inspector came out and inspected, I got approved.
He said the pipes are no big deal as the tanks are sanded. Rebar and mesh are not required but I am still going to do it to avoid the cement from pulling apart if I ever have a problem.
The question now in my head is to do it myself or have someone do it. The inspector said to do it myself. He said you did a fine job (depth,width,straightness,stone,layout) on the excavation and that is where most people screw up. So I now understand the process even more after talking to the inspector, so I am thinking more about doing it myself to save the cash. I dunno, I will price it out and make the final decision.
I plan to put electrical in and will install what is necessary for that in the concrete before I pour. I will not actually do electrical till next year as the whole property will be upgraded.
Thanks for the help.
Chris
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What I don't understand is you stated you knew all this was there, did the prep work, and intial excavations, now you're inquiring about its use as base under a foundation for garages.
My consideration, if knowing all this in advance, not advisable. Dave
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All, I knew the systems where there but being inexperience with the city inspectors/code/concrete I posted for advice. The yard is broken up in such a way (large trees(many),house.drive,existing garage, etc) that placing these garages anywhere else would be of a lot more of a issue. More then a few weeks went in placing these garages.
I will consider hiring the job out but I will have to weigh the good with the bad possibilities and make a decision. I am at this point a little more confident then I was when I originally posted this message. This fact, makes it a decision and not a necessity to hire it out.
Thanks all for the help, Chris
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