What is the difference between architectural and engineering drawings?

When you begin home renovations, you will likely need the help of construction professionals to plan your project. Depending on the type of renovation, this may involve architects and engineers drawing up specific plans. As each role entails different responsibilities, their respective designs will reflect their areas of expertise and limitations. In this guide, we explain the difference between architectural and engineering drawings and the situations when the latter are required. 

In order to understand the difference between architectural and engineering drawings, let's start with the essentials and list the typical drawings for each type of plan. 

What are architectural drawings? 

Essential information

Architectural drawings document a building’s existing conditions and contain guidelines for demolitions and changes, including which elements will be demolished or retained. 

Drawings for the proposed plans should include all relevant dimensions in width, length, and height (for rooms, doors, windows, stairs, and fixtures), materials used, proposed finishes, the location of specific equipment (such as plumbing, electricity, and ventilation), and suggested construction or assembly methods (for walls, partitions, floors, and roofs). 

In essence, architectural drawings should contain all the information necessary for an engineer to make accurate structural recommendations and all the specifications required for a contractor to begin renovations. 

List of typical drawings*

*The list of architectural drawings may vary depending on the parameters and scale of the project.

Existing Site and Demolition Plan

  • Photos of the existing building
  • Certificate of location 
  • Layout
  • Floor plans for all relevant levels
  • Elevation of all relevant facades

Construction Plan

  • Layout
  • Plan of all relevant floors
  • Elevation of all relevant facades
  • Sectional overview

Electrical and Mechanical Plan

  • Ceiling plan for all relevant floors
  • Cabinetry (built-in furniture)
  • Specifications for fixed furniture (plan, elevation, section, as necessary)

Stairs

  • Staircase expansion plan 
  • Staircase expansion elevation 
  • Cross-section of expansion, as necessary

Diagrams and Tables

  • Material composition (walls, partitions, floors, roofs)
  • Diagram of exterior and interior doors and windows
  • Construction details, as necessary

What are engineering drawings?

Essential information

Engineering drawings should provide new information that complements architectural drawings. Based on the architect's concept proposal, the engineer must design and size the structural elements of the building, such as foundations, beams, joists, bearing walls, columns, and lintels. More importantly, engineering drawings must include the relevant connection details between these structural elements.

List of typical drawings*

*The list of engineering drawings may vary depending on the parameters and scale of the project.

Existing Site and Demolition Plan

  • Floor plans for all relevant levels

Construction Plan

  • Floor plans for all relevant levels

Construction Details

  • Specific details for all component types

What is the difference between architectural and engineering drawings?

While the architect is responsible for the design of the new layout and the choice of building materials and finishes, the structural engineer is responsible for the design and dimensions of the structural elements, whether they are made of wood, steel, or concrete.

For example, if a plan proposed by the architect includes the demolition of an interior partition, it may be a load-bearing wall. This will have to be replaced by a beam and columns to redirect the loads previously supported by this wall. Although the architect can propose the installation and removal of a partition, they cannot account for the structural elements related to this intervention. 

In fact, since architects do not have the expertise to provide these guidelines, it is not their professional responsibility. According to Quebec law, the design and dimensioning of structural elements should be strictly reserved for engineers recognized by l'Ordre des ingénieurs du Québec. It should also be noted that in order to obtain a construction permit, the city always requires the submission of an engineer's drawings, in conjunction with architectural drawings for work that involves the modification of a building’s structure. 

Architects and engineers will be involved at different stages of your project, depending on what type of work is needed during your renovations. In short, architectural drawings help you define your new space and choose your building materials and finishes. Engineering drawings are used when alterations to structural elements are part of the construction, such as changes to a bearing wall.

Ready to start your renovation?

To help you plan your project, Billdr offers preliminary plans and support with building permits through our architectural design services.