Most estimating mistakes do not begin in the spreadsheet. They begin on the drawings, when something was read too fast or quietly assumed to be someone else's scope. Learning to read a plan set properly is the cheapest protection a bid has, because the drawings are the one document the owner and every competing bidder are all working from.
A plan set is not a single drawing. It is a coordinated package, and it only makes sense when the sheets are read in the right order and checked against each other.
Identify what you actually received
Start by inventorying the set rather than pricing it. A complete package usually contains:
- a cover sheet and drawing index
- general notes, abbreviations, and symbols
- site and civil drawings
- architectural floor plans, elevations, sections, and details
- structural drawings and foundation plans
- mechanical, electrical, and plumbing drawings
- schedules for doors, windows, finishes, and equipment
Specifications are normally a separate document and they carry requirements the drawings never show. If any of these pieces are missing, that is not a detail to resolve later. It is a scope risk, and it belongs on your question list before anyone starts estimating.
Read the cover sheet and general notes first
The cover sheet tells you the project name, location, owner, architect, engineer, sheet count, and revision dates. The general notes define how the drawings are meant to be interpreted. Read both before opening a floor plan.
This is also where you check the index against what is physically in front of you. A set that references sheet A-6 which was never issued is a set you cannot price confidently.
Confirm the scale and never trust a scaled dimension
Every sheet states its scale, and very few drawings stay accurate once they have been printed, scanned, or resized. Never pull a quantity off a drawing by measuring it with a scale ruler unless the documents explicitly permit it.
Use the written dimensions instead. Where a dimension is missing, that gap is a question, not a guess.
Read the sheets in discipline order
Read in the order the building is assembled:
- Site and civil — grades, utilities, access, and what the site allows you to do.
- Architectural — the layout, finishes, openings, and the owner's intent.
- Structural — foundations, framing, and the systems carrying the load.
- MEP — mechanical, electrical, and plumbing routes and equipment.
Reading in this order keeps you from planning a duct route through a beam you have not looked at yet.
Cross-check the drawings against each other
The most expensive scope gaps live between sheets, not on them. A wall shown on the architectural plan and changed on the structural sheet is a conflict. A door schedule that does not match a floor plan is a conflict.
When you find a conflict, write it down as a question with both sheet numbers attached. A conflict you keep in your head becomes somebody's change order later.
Treat the specifications as part of the drawings
The specifications routinely override or expand what the drawings show, particularly on materials, submittals, testing, and installation methods. A finish schedule names a product; the specification tells you who installs it and what the substrate must be.
Mark up as you read
Reading a plan set should produce a marked-up set and a running list of questions. Note assumptions you are making, items that appear to be by others, and anything the documents leave unclear.
That list is the beginning of your bid: it becomes your RFIs, your exclusions, and the assumptions you carry in the proposal.
BidPacket turns an uploaded plan set into a first-pass scope breakdown, materials checklist, and list of items needing confirmation. It does not replace a careful read, but it keeps the details from staying buried in the drawings.