An addendum replaces one flooring plan the day before a bid is due. You need to explain which square footage changed and whether the change crosses a carton threshold. In a construction quantity takeoff, keep the measured area, deduction rule, and order quantity in separate fields. The drawing revision tells the reviewer which number belongs in the bid.
Use one row per measurable scope item in an identified location and drawing revision. Preserve the markup behind the measurement and calculate ordering adjustments downstream (waste and pack size can differ by material). When a sheet changes, review the affected rows and retain the earlier version so the new bid quantity has an explainable difference.
Copyable fields for a measured quantity
Source and scope. Bid package [ ]; takeoff item ID [ ]; trade and work area [ ]; item description [ ]; drawing sheet and detail or model view [ ]; revision and issue date [ ]; addendum [ ]; measurement markup [ ]; inclusions and exclusions [ ].
Measurement. Method [count / length / area / volume]; drawing scale or known check dimension [ ]; gross quantity and unit [ ]; deductions and basis [ ]; net quantity and unit [ ]; any dimension or conversion assumption [ ].
Handoff. Waste rule and source [ ]; quantity before pack rounding [ ]; purchase unit and coverage per unit [ ]; rounded purchase quantity [ ]; estimate item or cost code [ ]; supersedes [ ]; measured and reviewed by [ ]; review status and date [ ].
Give the same scope item a stable ID across versions. Keep different locations or measurement units separate even when the scope descriptions match. The estimator can then approve a crosswalk into construction cost codes without losing the split that explains the quantity.
Check the measurement method on the source drawing
Pick the unit the scope needs before tracing the drawing. Count fixtures as each, measure a pipe run in linear feet, and record a finish area in square feet. Autodesk’s 2D takeoff instructions show how those distinct measurements are entered. For a volume derived from area, preserve the depth and unit conversion in the calculation. Adding measurements with incompatible units makes the result impossible for a reviewer to reproduce.
Verify the scale against a known dimension for the part of the drawing being measured. Autodesk documents calibrating a takeoff sheet from a known distance in its Takeoff documentation. If an enlarged detail uses a separate scale, verify it before taking any dimensions from that detail. Flag a scope item for clarification when the source lacks a dimension you can use.
Record how you treat openings, cutouts, and scope edges. A deduction needs a measured quantity and the rule that allows it, such as excluding a fixed equipment footprint from flooring under the bid instructions. Apply waste to the net quantity only when that is the agreed basis. Give the reviewer enough detail to reproduce gross minus deductions before checking how much to buy.
Recalculate the flooring row after an addendum
Assume the initial flooring plan shows 1,200 square feet of gross area in a corridor and a 60-square-foot fixed equipment footprint excluded under the bid scope. The addendum enlarges the gross area to 1,260 square feet and leaves that footprint unchanged. Use a hypothetical 8% waste allowance on net area, and assume the chosen tile comes in cartons covering 24 square feet. Use full cartons for this order and assume no stock is available for the job.
| Takeoff record | Gross less deduction | With waste | Rounded order |
|---|---|---|---|
| Original corridor plan | 1,200 − 60 = 1,140 sq ft | 1,231.2 sq ft | 52 cartons |
| Addendum corridor plan | 1,260 − 60 = 1,200 sq ft | 1,296 sq ft | 54 cartons |
| Change for the estimate | +60 sq ft net | +64.8 sq ft | +2 cartons |
Round up after dividing the adjusted area by carton coverage. The original plan requires 51.3 cartons before rounding, while the revised requirement is 54 cartons. Retain the calculation and report the two-carton difference after rounding both complete requirements. Rounding the incremental area as if it were a new standalone order would give three cartons.
Keep both measured rows and mark the old one superseded in the current estimate view. Autodesk documents point-in-time snapshots in Takeoff that retain quantities and the source sheet or model versions at the time of capture. Whichever tool you use, recheck transferred markups against the new revision before relying on them. See Autodesk Takeoff pricing if you are evaluating seats and review access for that workflow.
Where Permute fits in the estimating handoff
Permute sells connected business data, custom applications, and governed analysis. We can bring permitted takeoff exports and estimating tables together using the bid package, item ID, and revision your team supplies. Keep rows that cannot be linked to a reviewed estimate item visible for correction.
We can use the issued drawing list to resolve which revision belongs with each estimate line and apply approved unit conversions without discarding the measured unit. A bid reviewer can trace a changed quantity to the export and markup reference behind it, subject to their access permissions.
Compare takeoff revisions alongside the estimate
Start with permitted exports for one trade package and the item identifiers you use to tie them together.
Keep measurement and scope review with the estimator
We read the records your team makes available and leave changes to drawings, takeoff markups, and estimates in their source tools. Have the estimator verify scale, scope edges, and measurement rules before a quantity is approved. An export preserves what was measured at its cutoff and needs review when the drawing changes.
Send the checked revision to the bid team
Include the issued drawing list, current takeoff rows, their markups, and the unresolved scope questions in the handoff. If the same item appears on both a model and a sheet, identify which measurement governs that location and preserve the other as a check. Keep the reviewed estimate export with the drawing set so the next change starts from the same quantities.
A usable takeoff records where a quantity came from, how it was measured, and which revision supports it. Keep scope deductions, waste, and pack rounding separate so a change can be traced through each calculation. In the corridor example, the addendum adds 60 square feet to the measured scope and two cartons to the order. Carry the revised row to the bid and keep the superseded row for comparison.
Review the link between drawings, takeoff, and bid quantities
Bring a redacted revision example to discuss which records a reviewer needs to trace the estimate.
Questions about checking takeoff quantities
Should I round purchase quantities for each room or for the whole order?
Apply pack rounding at the level you will order. Keep each measured room visible and aggregate compatible material requirements before rounding when they will share one order. If rooms have separately ordered kits, preserve that constraint in the calculation.
What if the drawing and model show different quantities?
Keep both source references and use the precedence agreed for the bid package. Leave the item under review when the governing revision or intended scope is unresolved.
Does the same waste factor apply to fixtures and sheet goods?
Use the approved rule for each item. A specified spare fixture belongs in a count with its own basis, while cut losses on sheet goods can depend on the layout and the sizes sold.