Flatwork is placed after the walks, driveway, and patio have been cut by the tractor contractor (you may also be required to get a city inspection). It might be a good idea to pour back patios and pads for air condition compressors at this time also.
Materials required for this job consists of economy grade 2x4s and 1x4s, 1×2 and 1×4 redwood, 1×4 black joint material, 6 ga. wire mesh or #3 rebar, and concrete. All of this material can either be supplied by the contractor, or provided by you, but be clear about this during initial negotiations.
If you are contracting this work out, you need to provide a plot plan to the contractor so that you can ensure flatwork forms are installed in the proper location and to guard against encroachment on any easements. The contractor sets the forms, installs redwood (control joints set at prescribed intervals) and black joint (expansion material between separate pieces of concrete), grades the flatwork sand to assure a 4 inch thickness of concrete, sets the driveway in-turn, then places and finishes the concrete. Prior to setting forms for the driveway in-turn, the curb must be cut and removed.
You should visually check the flatwork for compliance with your standards (as well as city building codes) prior to allowing the contractor to pour the concrete. The in-turn inspection is also at this time and should be called in to the city with sufficient lead time to ensure the inspectors availability. The forms must be ready for concrete placement when the inspector arrives. Know the requirements for your community and, when possible, meet the inspector at the job site. Any corrective action specified by the inspector shall be corrected prior to concrete placement. Place the inspection certificate someone safe (inspectors are known to loose them).
The concrete finisher should be responsible for staying on the job site until the concrete has sufficiently hardened to protect against vandalism. Twenty-four hours after placement the contractor can come back and remove the form boards.
Pre-Placement Checklist for Flatwork Concrete
- Schedule flatwork and/or in-turn inspection, as required
- Check for 4″ concrete thickness in forms. Use additional flatwork sand to reduce the amount of concrete needed, if necessary.
- Check driveway in-turn for proper curb cut (as specified in applicable code requirements).
- Cut should extend at least 6 inches into street
- Allow for a 5 foot radius on each side of the in-turn
- In-turn must be free of loose debris and no standing water
- Check the live ends on post tension cables to ensure that they do not interfere with the flatwork forms (examine garage and porch areas)
- Ensure that the patio is sloped to the nearest side of the lot for proper drainage (no more than 2 inches in 10 feet)
- Maximum step height at front & rear entries is 8 inches. Any greater height requires an added step(s)
- Check that the patio surface is 4 – 7 inches below the top of the slab
- Ensure the public walk is set in the right-of-way; lines up with existing sidewalk; and complies with local requirements.
- Check the slope of the public walk. It should angle 1 to 2 inches from rear edge to front edge.
- Check the driveway is 1 inch lower than the garage trough
- The forms must be ready for concrete placement when the inspector arrives (if inspection required). When possible, meet the inspector at the job site
- Rear entry stoop shall be 42 inches square. Use black joint at slab edge.
- A/C Compressor pad dimensions vary by unit installation
- Single System – Typically 36″ x 36″ Concrete Pad (4″ thick)
- Double System – Typically 84″ x 36″ Concrete Pad (4″ thick)
- Ensure AC pads are physically seperated from the foundation to prevent vibrations and excess noise
Flatwork Placement Checklist
- Make sure you have a concrete washout location to be used by truck drivers
- Check and confirm black joint installation. Ensure it is level with the new concrete
- Check all joints for proper edging (i.e. picture frame use)
- Check for proper edging where concrete meets the form boards
- Check patio, stoop, and AC pads for trowel smooth finish
- Check drives/walks for a light broom finish
Checklist for Flatwork Concrete Post-Placement
- Check for concrete spillage outside of forms. Stack all spillage in one pile at curbside
- Ensure form boards have been pulled and stacked neatly
- Make sure all trash is in the trash barrel and construction debris is cleaned
