Sidewalk and flatwork takeoff: SF, SY and thickened edges

Flatwork is the scope where units cause the most confusion. Plans dimension it in feet, engineers summarize it in SF or SY, subs bid it in SF, and concrete arrives in CY. Getting from one to another without losing track of thickness is most of the job.

Measure by section thickness

Trace each area of flatwork as a closed polygon and keep sections separate. A typical site has 4" walks, 6" walks or aprons at vehicle crossings, and 6"–8" pads at dumpsters and equipment.

So 3,000 SF of 4" walk is about 37 CY of concrete before waste, and 600 SF of 6" dumpster pad is about 11 CY. Add a waste allowance from your own history — narrow walks and small pours waste more than large slabs.

Handle the edges and the extras

• Thickened edges, measured in LF where the detail calls for them.
• Reinforcement: welded wire, fiber, or rebar mats — by SF or by weight.
• Control and expansion joints, in LF, plus sealant where specified.
• Aggregate base under the slab, per the detail thickness.
• Forming and finishing specialties: broom finish, exposed aggregate, integral color, stamped patterns.

ADA work is its own set of quantities

Curb ramps, flares, landings and blended transitions each have geometry and slope requirements defined in the details, and they cost more per SF than straight walk. Take them off individually.

1. Count ramps by type and take off their concrete area separately.
2. Count detectable warning surfaces, by EA or SF as your supplier quotes them.
3. Measure landings at doors and at ramp tops where they are shown as separate pours.
4. Note any handrail, guardrail or edge protection called out at ramps or steps.

Where a walk crosses a driveway, the detail usually thickens the section and may add reinforcement. Splitting the walk at that crossing is a small amount of extra work that prevents an underpriced apron.

Demolition and replacement

On renovation and infill projects, removal quantities are often larger than new construction. Take off removal areas separately from the demolition plan, along with saw cutting in LF and disposal in CY or tons, and keep them out of the new-work conditions so both can be priced and reviewed independently.

Quick sanity checks

• Does walk width times length match your polygon area on a straight section?
• Are walks continuous through crossings and ramps, with no gaps at sheet edges?
• Does your base stone area match your concrete area?
• Are pads that appear on the architectural site plan but not the civil plan accounted for?