The "plans" are actually part of a larger set of Contract Documents. If a conflict arises between different parts, a strict hierarchy applies to resolve the contradiction. While the specific contract always dictates the final rule, standard industry practice dictates the following hierarchy:

• Project Specifications (The "Specs"): Written specs detailing exact material brands, installation methods, and quality standards ALWAYS govern over the drawings. If the drawing says "Paint" but the Spec book says "Epoxy Coating," you must provide the epoxy coating.
• Detailed Drawings over General Plans: A large-scale, specific detail (e.g., a 1:10 drawing of a handrail connection) supersedes a small-scale, general drawing (e.g., a 1:100 floor plan showing a line for the stair).
• Written Dimensions over Scaled Dimensions: Never physically scale a printed drawing with a ruler if a number is explicitly written; the written dimension is final and legally binding. Paper stretches and shrinks, distorting the scale.

Drawings are divided into disciplines, indicated by a prefix letter.

• G-Series (General): Project title sheet, drawing index, general location map, symbols legend.
• A-Series (Architecture): Site plan, floor plans, exterior elevations, building sections, roof plan, reflected ceiling plans (RCP), door/window schedules, and architectural finish details (e.g., A-1, A-2... A-10).
• S-Series (Structural): General structural notes, foundation plan, framing plans (floor by floor), structural elevations/sections, column/beam schedules, and rebar detailing (e.g., S-1, S-2).
• P-Series (Plumbing): Sanitary layout, water supply layout, isometric diagrams, and plumbing fixture schedules.
• E-Series (Electrical): Lighting layout, power layout, auxiliary layout (fire alarm, data/tel), panel board schedules, and single-line riser diagrams.
• M-Series (Mechanical): HVAC ductwork layout, equipment schedules, and fire sprinkler piping plans.

• Very Thick/Heavy Lines: Indicate elements that have been physically cut by the imaginary section plane (e.g., the perimeter walls on a floor plan, or the concrete slab in a building section).
• Medium/Thin Lines: Indicate elements that are visible, but lie "beneath" or "behind" the cutting plane (e.g., the steps of a staircase viewed from above, or a window sill).
• Dashed Lines: Indicate elements that exist, but are hidden from the current view. (e.g., a massive foundation footing buried underground shown on a site plan, or a structural beam running in the ceiling shown on a floor plan).
• Hatching: Used heavily in sections to immediately identify materials without needing text labels (e.g., parallel diagonal lines for masonry block, a stippled sand pattern with triangles for concrete).

Estimators interpret plans to extract precise quantities of materials (QTO).

• Linear Measurement: Taking off total lengths of items like baseboards, piping, or electrical conduit directly from the scaled plan.
• Area Measurement: Calculating square meters of flooring, roofing, or wall paint using dimensions on the plans.
• Volume Measurement: Deriving cubic meters of concrete or earthwork by combining area from the plans with depth from the sections.
• Count Measurement: Manually enumerating individual items like doors, light fixtures, or plumbing valves.

• Color Coding (Highlighting): Never trust your memory. As you count items (like doors) or measure lengths of wall on a printed plan, highlight them. Yellow for counted, Green for measured length, Pink for calculated area. An un-highlighted line means you missed something; double-highlighting means you counted it twice.
• The Centerline Method (Walls): When calculating the total length of exterior walls, do not just add the outside perimeter dimensions. If you do, you will double-count the corners where the wall thickness overlaps. Calculate the length along the centerline of the wall thickness for exact volume calculations.