Takeoff is where a quote is won or lost. Get the pieces and weights right and the rest of the job has a solid footing. Miss a section or count a structure twice and you have either left money on the table or priced yourself out. Here is how the two most common structures come apart.
What takeoff is doing
Takeoff turns a set of plans into quantities: which structures, how each one breaks into castable pieces, their weights, and the accessories that hang off them. Everything downstream, the quote, the shop drawings, the schedule, rides on getting this right.
Manhole takeoff, step by step
- Read the structure schedule. The plans usually list each structure with its rim and invert elevations and pipe sizes. Start there.
- Get the overall height. Subtract the lowest invert from the rim elevation. That height, plus the base slab and the top, tells you how tall the barrel has to be.
- Break it into pieces. A manhole is rarely one casting. It is a base, one or more riser sections, and a top or cone. Pick the section heights that add up to your barrel height using the risers your plant actually makes.
- Count and weight the pieces. Count each base, riser, and top, and figure the weight of each from its dimensions and wall thickness. Weight is what you will price on.
- Add the accessories. Frame and cover or grate, steps or a ladder, and the pipe openings. Each pipe is a blockout at its invert and angle, and it is easy to forget one.
Box culvert takeoff, step by step
- Read the span and rise. Box culverts are called out by their inside span and rise, for example an 8 by 4. That sets the cross section.
- Get the run length. The total length of culvert you have to supply, from the plan and profile.
- Break the run into segments. Culvert ships in standard laying lengths. Divide the run by your segment length and account for the partial piece at the end.
- Account for wall and slab thickness. The section's wall and slab thickness drive the concrete volume and the weight per foot.
- Add the ends and specials. Headwalls, wingwalls, aprons, and any skewed or beveled end sections. These are separate pieces and separate weights.
Where the double-counts hide
Count the job once
The most expensive takeoff mistakes are quiet. A structure that appears on both the plan and a detail sheet gets counted twice. An alternate or a revised quantity gets added instead of replacing the original. A pipe opening gets missed because it was only shown in the profile. Reconcile your count back to the structure schedule before you price anything.
Versions and alternates are the usual culprit. When a job gets revised, the safe move is to replace the old quantity, not add to it, and to keep one authoritative count you can trace back to the plans.
From takeoff to price
Once the pieces and weights are down, most precast is priced by weight, with accessories, special finishes, and freight added on top. A tool built for precast takeoff carries the quantities straight into the quote so nothing is re-keyed. That is what DhyanaTakeoff does, and it syncs one click into a DhyanaERP quote. For how pricing builds on the takeoff, the Precast Edition page walks the whole quote-to-cash path.