By Michael in Cave Creek, AZ on 6/4/2006
Typically an excavation and grading company will prepare the site. This includes clearing, hauling of the debris, and grading. A full service grading company will bring in fill and haul off spoils to build a level pad. You will probably need to arrange for a surveyor. Some grading companies include compaction testing for any fill work that they do in their scope of work/others don't. This is a question worth asking if you are filling more than a foot or so or if your permitting agency requires a particular level of compaction (e.g. 90 or 95%)
A concrete company can dig your footings, put in the re-bar, and form and pour your footings. They often sub-out digging of footings to a backhoe service, but they do the rest of the footing work with their crews.
Once the footings are poured call your plumber to rough in your drain lines and any underslab water lines that you might want. Also some people like to put an electrical outlet in the middle of a living room floor for a table lamp. You would need to arrange for that to be put in also at this time. If you are doing a fancy custom home you may want underslab air return ducts which would be a separate company recommended by your HVAC contractor.
If you are in a rocky area or have particular inspectors you may need to shade your plumbing with sand. Both the plumber and the footing contractor typically this work from their scope. So, be sure to get that covered in somebody's scope of work.
Once the plumbing and underslab work has passed inspection, call the concrete contractor back, they will backfill the pipe trenches and put aggregate material down under the slab. They often sub this work out to a tractor service, who places and levels the base course.
When the base course is leveled. The concrete contractor will call you and tell you which day the pour is scheduled. At this point call your Pest Control company, they will come during the night before the pour and pre-treat for termites. This will allow you to get a termite warranty that your lender is very likely to require before making a loan on the property.
In summary, for a typical house there are at least four subs that you need to hire before the slab is poured, for a slab on grade footing.
1. Grading Contractor
2. Concrete Contractor
4. Pest Control Company (in states with termites)
You can break these tasks up further and involve more company's if you want. This might save you a little mark-up, but will make your job coordinating trades harder.