What Are Shop Drawings in Construction? A Comprehensive Guide

May 21, 2024

When embarking on a construction project, understanding the difference between construction drawings and shop drawings is crucial. These two types of drawings serve distinct purposes and are essential for accurate, efficient, and successful project execution.

Overview

Construction drawings and shop drawings are both integral parts of the construction process. They guide various stakeholders, from architects and engineers to contractors and fabricators, ensuring the project is completed as envisioned. This article explores the unique purposes, creation times, responsibilities, accuracy, and details of these drawings.

Construction Drawings (CD Sets)

Definition & Purpose

Also known as working drawings or architectural construction documents, construction drawings are created by architects to visualize architectural elements before construction begins. These drawings serve as bid drawings for contractors, providing essential specifications on architectural components, structural use, features, appearance, materials, equipment, and more.

Usage Example

A US architectural engineering firm used construction drawings extracted from a 3D MEP model. This helped in accurate fabrication and reduced onsite rework.

Details Included

  • Elevations (Interior and Exterior)
  • Plans (Framing, Utility, Roof, Electrical & Lighting)
  • Details (Interior and Exterior, and Structural)
  • Sections (Buildings and Walls)
  • Schedules (Doors and Windows)
  • Finishes
  • MEP information

Accuracy & Liability

Construction drawings are created before contractors are hired, and they may contain errors. These drawings are often marked “Not for Construction” to mitigate risks. They serve as a reference for budgeting and producing change orders.

"exterior stair V02 wood treads_C110" by Caliper Studio is licensed under CC BY-NC-SA 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-sa/2.0/.

Shop Drawings

Definition & Purpose

Shop drawings are detailed documents that fabricators use to understand component manufacturing and installation. Created by contractors, subcontractors, manufacturers, or suppliers, usually after a contract is signed, these drawings provide greater elaborations of construction drawings, including accurate dimensions, timestamps, and assembly details.

Usage Example

A European BIM consultant firm’s institutional project used shop drawings derived from Revit models to resolve clashes and achieve cost savings.

Details Included

  • Component identification with tags and dimensions
  • Information about interferences and adjacent components
  • Coordinates for site surveying and location
  • Size of openings
  • Clearances, Assembly details, Section views
  • Title block with project specifics
  • Fabrication standards, Installation and erection data

Accuracy & Liability

Shop drawings reflect in-field conditions with precise dimensions and need the construction team’s approval. They are used frequently post-project commencement and often serve as an assembly manual.

"exterior stair V01 perf treads_C110" by Caliper Studio is licensed under CC BY-NC-SA 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-sa/2.0/.

Key Differences Highlighted

Creators

Construction Drawings: Created by architects or engineers at the owner's request.

Shop Drawings: Created by contractors or subcontractors after signing the contract.

Creation Timing

Construction Drawings: Generated before the start of construction.

Shop Drawings: Derived from contract specifications before the project begins.

Purpose

Construction Drawings: Define the overall project intent and guide decision-making.

Shop Drawings: Provide detailed specifics for fabrication and installation.

Accuracy

Construction Drawings: Can contain potential errors and are often marked “Verify-in-Field.”

Shop Drawings: Highly precise, time-stamped with accurate dimensions.

Liability

Construction Drawings: Contains a “Not for Construction” label to mitigate risks.

Shop Drawings: Require detailed team approval and provide a precise depiction of the work scope.

The nuanced roles and responsibilities associated with construction and shop drawings significantly impact project success. Understanding these differences helps in perfect execution and collaboration among the stakeholders involved in a construction project.

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