Structural drawings and calculations

Planning for a property extension always starts with the foundations

Structural drawings and calculations

Why do I need structural drawings and calculations?

In any construction project, structural drawings play a crucial role in ensuring the safety and stability of the building. These highly technical documents provide detailed information about the design and construction requirements, guiding engineers, architects, and builders throughout the project. If you’re unfamiliar with reading structural engineer drawings or need a refresher, this comprehensive guide will walk you through the key elements and terminology involved.

What are Structural Drawings?

Structural drawings are a set of technical documents created by structural engineers that outline the design and specifications for the construction of a building. These drawings are essential for ensuring that the structure is built safely and in compliance with building codes and regulations. They provide detailed information about various structural elements, including foundation plans, floor plans, framing plans, and roof plans.

Types of structural drawings:

Foundation Plans

Foundation plans serve as the starting point for any construction project. They provide critical information about the foundation’s design, ensuring its stability and ability to support the weight of the entire structure. Foundation plans detail the type of foundation to be used, such as strip, raft, pile, or pad and beam foundations.

Floor Plans

Floor plans give an overview of the layout and dimensions of each floor in the building. They show the location of load-bearing walls, joists, and other structural elements necessary for the safety and stability of the building. Floor plans provide a basic visual representation of the space and help in determining the overall functionality of the structure.

Framing Plans

Framing plans provide detailed information about the framing system of the building. These plans specify the placement of studs, rafters, beams, and other structural members. Framing plans are crucial for ensuring that the building’s frame can support the weight and loads imposed on it.

Roof Plans

Roof plans outline the design and construction details of the roof. They specify the placement of trusses, sheets, and other structural components. Roof plans take into consideration factors such as the load-bearing capacity of the roof and ensure its proper installation and stability.


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When to engage with a Structural Engineer

Initial Design Phase:

When: As early as possible in the project, during the conceptual and schematic design phases. Why: The structural engineer can collaborate with the architect and other design professionals to provide input on the structural feasibility of the design. This early involvement helps shape the project’s overall layout and ensures that architectural concepts align with structural requirements.

Design Development Phase

When: During the design development phase, after the project’s basic design concepts have been established.

Why: The structural engineer can refine the structural design based on detailed information and work closely with other consultants to integrate structural elements seamlessly with architectural, mechanical, and electrical systems.

Structural drawings play a pivotal role in every project, whether it involves the removal of a load-bearing structure or the construction of a new house. These drawings serve as a guiding compass for both contractors and architects.

Understanding structural drawings is essential for anyone involved in a construction project. These drawings provide crucial information about the design and construction requirements, ensuring the safety and stability of the building. By familiarizing yourself with the different types of drawings and key elements, you can effectively read and interpret structural engineer drawings. Always consult with a professional engineer if you have any questions or need further clarification on the drawings.

Remember, structural drawings are just one piece of the puzzle. To comprehensively ensure the success of your project, it’s important to consult with experts in other areas, such as CCTV surveyors, party wall surveyors, and architectural technicians. By working together with professionals in various fields, you can achieve a well-designed and structurally sound building.

Key Elements of Structural Drawings

Title blocks 

Title blocks provide basic information about the drawing, such as the project name, the name of the architect or engineer who created the drawing, and the date it was created. These details help identify and organize the drawings.

North Arrow

The north arrow indicates the orientation of the property on the drawing. It helps orient everyone working on the project and ensures that they have a consistent reference point when interpreting the drawings.


Dimensions are critical in construction, as they provide the exact measurements of all elements on the drawing. They ensure that everything is built to the correct specifications, allowing for precision and accuracy during the construction process.


Notes provide additional information about the drawing, such as construction methods, load limits, or other important details. They offer clarity and guidance to those interpreting the drawings.


Will you need to visit?

In many cases, a structural engineer will need to visit a site before producing structural drawings. Site visits allow the engineer to gather important information about the existing conditions, such as the terrain, soil properties, surrounding structures, and any potential obstacles or limitations that could affect the design and construction of the project. Here’s why site visits are important:

Site-Specific Information

Each site has its unique characteristics and challenges. By visiting the site, the structural engineer can assess factors like soil stability, drainage patterns, wind loads, seismic considerations, and other site-specific conditions that will influence the structural design.

Accurate Measurements:

Precise measurements of the existing structures, topography, and any relevant features on the site are crucial for creating accurate structural drawings. These measurements help ensure that the new design integrates seamlessly with the existing conditions.

Identification of Constraints

Site visits help engineers identify any constraints posed by nearby structures, utilities, vegetation, or other physical elements. This information helps them design structures that adhere to zoning regulations and do not negatively impact surrounding environments.

Visual Assessment:

A firsthand visual assessment of the site allows the engineer to identify potential issues that might not be apparent from drawings alone. This includes factors like accessibility challenges, potential construction sequencing problems, and site-specific safety concerns.

I have estate plan is that enough?

While a structural engineer can certainly use estate agent plans as a reference, these plans might not always provide the detailed information required for developing accurate structural drawings and designs. Estate agent plans are often created for marketing purposes and may not include all the technical details necessary for structural analysis and design. Here are some considerations:

Level of Detail:

Estate agent plans are generally created to showcase the layout and features of a property to potential buyers or renters. They may lack the level of detail required for a structural engineer to fully understand the existing conditions, including dimensions, load-bearing walls, structural elements, and other crucial information.


Estate agent plans might not always be precise or to scale. They could be simplified for presentation purposes, potentially leading to inaccuracies in measurements and dimensions.

Omission of Critical Data:

Estate agent plans may not include important information about the structural systems, material properties, foundation conditions, soil data, and other site-specific factors that a structural engineer needs to consider when creating design plans.

In most cases, it’s recommended that a structural engineer conducts a site visit to accurately assess the existing conditions and gather the necessary data for designing safe and effective structural solutions.

Structural survey London costs

What is the difference between structural drawings and architectural drawings?

Structural drawings and architectural drawings are both essential components of the construction documentation process, but they focus on different aspects of a construction project. Here’s a breakdown of the key differences between the two:

Architectural Drawings: These drawings primarily focus on the aesthetics, layout, and spatial arrangement of a building. They detail the overall design, appearance, and functionality of the structure. Architectural drawings include floor plans, elevations, sections, and other views that help visualize the building’s external and internal features.

Structural Drawings: Structural drawings focus on the structural integrity and stability of the building. They provide detailed information about load-bearing elements such as beams, columns, foundations, and other structural components. These drawings specify how the building’s structure will support its weight and various loads over time.


Architectural Drawings: These drawings show elements like walls, windows, doors, staircases, room layouts, finishes, and aesthetic details. They convey the overall appearance and design intent of the building.

Structural Drawings: These drawings detail the dimensions, sizes, materials, and reinforcement of structural elements. They include information about the arrangement of beams, columns, slabs, and foundations, ensuring that the building can withstand its intended loads and remain stable.

Structural Drawings

Structural drawings and Building Control drawings are both essential components of the construction documentation process, but they serve different purposes and focus on different aspects of a building project. Here’s a breakdown of the key differences between the two:


Structural drawings focus specifically on the design and layout of the structural components of a building. These components include foundations, columns, beams, slabs, walls, roofs, and other load-bearing elements.


Structural drawings provide detailed information about the sizes, shapes, materials, and connections of the structural elements. They also include information about loads, forces, and calculations that ensure the structural integrity of the building.


Structural drawings guide the construction team in implementing the structural design as intended by the structural engineer. They provide the information needed to ensure that the building’s structure can safely support the loads it will experience over its lifespan. To add further Structural drawings must follow Approved Document A and Eurocodes

Building Control Drawings:

Building Control drawings, also known as construction drawings or working drawings, encompass a broader range of information about the entire building project. Their primary purpose is to communicate the design intent and provide comprehensive guidance for construction. These drawings must follow specific legislation


Building Control drawings cover architectural, structural, mechanical, electrical, plumbing, and other systems that contribute to the building’s construction. They detail the layout, dimensions, materials, finishes, and assembly methods


Building Control drawings serve as a reference for obtaining permits and approvals from regulatory authorities. They ensure that the construction process follows local building codes, regulations, and standards, and that the building will be safe, accessible, and compliant.

In summary, structural drawings focus specifically on the design and layout of load-bearing elements, while Building Control drawings provide a comprehensive overview of the entire construction project, addressing various aspects beyond just the structural components. Both types of drawings are crucial for the successful execution of a building project, as they ensure that the design is accurately translated into a safe and compliant built environment.