Concrete volume is only one part of a bid review. The estimator needs to know how the pours will be arranged and what the supplier's price includes. Otherwise, the takeoff can be correct while the job costs more than allowed.
Here are ten mistakes that deserve your attention across the drawings, material orders, and site work.
Start with the drawings
1. Keeping quantities from a superseded detail. An addendum may change a footing’s dimensions after the takeoff is complete. Revise the affected quantities wherever they appear in the estimate. Also, make it a point to check the bid summary separately to confirm that it carries the updated total.
2. Applying one scale to every sheet. Calibrate against a labeled dimension. The scale printed on a drawing won't correct a PDF that has been resized. Enlarged details need their own check.
3. Counting a thickened edge incorrectly. Consider a six-inch slab with an edge that is twelve inches deep overall. Once the six-inch slab volume has been measured, that edge needs another six inches of depth counted across its width. Adding the full twelve inches would count part of the concrete twice.
What will actually be ordered?
4. Asking the supplier to quote strength alone. The specified mix may also require fibers or other additions. Send the complete requirements with the quotation request so the price covers what will actually be ordered.
5. Omitting steel at splices. Two overlapping bars use more steel than one uninterrupted length covering the same distance. Calculate the laps shown in the reinforcement details, along with specified hooks and bends.
6. Ordering exactly the drawing volume. Excavation wider than planned has to be filled. Uneven ground and placement losses can also increase the requirement, as NRMCA's yield guidance explains. Any allowance should have a recorded basis.
Price the work around each pour
7. Reuse allowed for, handling left out. Reusing panels means paying for stripping, cleaning, and erection on each cycle. The schedule also has to leave enough time between pours to make that reuse possible. Two simultaneous pours may require additional panels.
8. Copying another job's labor allowance. Several small pours mean several setups. Include the time spent preparing each separate placement. A production rate from continuous placement may leave those hours out. Use previous job records that identify the quantity placed, hours worked, and delays.
9. Comparing concrete rates before reading delivery terms. Waiting time and small-load fees can change the total. Pump hire may have minimum charges even for a short pour.
10. Leaving finishing and curing inside an unexplained allowance. The specified surface finish determines the operations and equipment needed. Curing also needs pricing against the specified method. A materials allowance alone won't cover the crew's time to perform that work.
