Structural Drawings vs Structural Calculations: What’s the Difference?

What Is a Structural Calculation Pack?

A structural calculation pack is the collection of calculations relating to the project.

For example:

Calculation Index

B1 — rear steel beam

B2 — internal steel beam

C1 — steel column

J1 — floor joists

F1 — foundation

Each section can contain the relevant structural checks.

What Is a Structural Drawing Pack?

A structural drawing pack can include:

• structural general arrangement plans;
• sections;
• details;
• schedules;
• connection details.

The amount depends heavily on the project.

What Is a General Arrangement Drawing?

A General Arrangement, often shortened to:

GA

shows the overall structural layout.

It can identify:

• beams;
• columns;
• walls;
• slabs;
• foundations;
• gridlines;
• structural references.

For a simple residential extension, the equivalent may be much simpler than a commercial structural GA set.

Are Structural Drawings Construction Drawings?

They can form part of the construction information.

But the term:

construction drawings

is broader.

Construction drawings can include:

• architectural drawings;
• structural drawings;
• mechanical drawings;
• electrical drawings;
• details.

What Are Technical Drawings?

“Technical drawings” is another broad term.

In residential Building Regulations work, it can refer to drawings that show:

• construction build-ups;
• dimensions;
• details;
• regulatory information.

Structural drawings are one type of technical drawing.

Planning Drawings vs Structural Drawings

Planning drawings are prepared primarily to explain the design for planning purposes.

They typically show:

• layout;
• appearance;
• scale;
• relationship to site.

They usually do not contain enough technical structural information to replace structural drawings or calculations.

Can Planning Drawings Be Used to Prepare Structural Calculations?

Yes.

Accurate planning or architectural drawings can provide an excellent starting point.

A structural designer can use them to establish:

• geometry;
• opening sizes;
• room positions;
• walls above.

Additional structural information may then be required.

Do I Need New Drawings If I Already Have Planning Drawings?

Not necessarily from scratch.

Existing drawings can often be developed into:

• Building Regulation drawings;
• structural information.

This can avoid unnecessary duplication.

What If My Planning Drawings Were Prepared by Another Architect?

They may still be usable, subject to:

• accuracy;
• suitability;
• rights to use/reproduce/adapt them.

The technical designer should confirm what information can be relied upon.

Structural Drawings vs Architectural Drawings

Architectural drawings usually focus on:

• layout;
• spaces;
• appearance;
• dimensions;
• finishes.

Structural drawings focus on:

• load-bearing elements;
• beams;
• columns;
• foundations;
• structural connections.

They overlap, but serve different purposes.

Does an Architect Produce Structural Drawings?

Potentially.

Some architectural practices prepare structural information where they have the appropriate competence and professional scope.

Others appoint or coordinate a structural engineer.

The important point is that structural design must be undertaken competently.

Does a Structural Engineer Produce Architectural Drawings?

Usually not as their primary role.

Structural engineers normally focus on:

• structural design;
• analysis;
• structural drawings.

Architectural and Building Regulation drawing work can be carried out separately.

Can One Company Do Both?

Yes.

For residential projects, it can be very efficient for one service to coordinate:

• Building Regulation drawings;
• structural calculations.

That can reduce the risk of one package contradicting another.

Why Coordination Is Valuable

Consider this:

Architect Draws

4.5m opening.

Structural Designer Calculates

4.0m opening.

Builder Prices

4.5m steel.

Fabricator Receives

4.0m structural schedule.

This creates a problem.

A coordinated technical package should catch discrepancies before construction.

What Does Part A Require?

Part A of the Building Regulations deals with:

Structure.

Approved Document A provides guidance in England covering structural matters including:

• loading;
• foundations;
• walls;
• floors;
• roofs;
• chimneys.

Structural calculations can provide evidence that particular structural elements satisfy the relevant requirements.

Do Approved Documents Require Structural Drawings?

Approved Documents set out guidance on ways of achieving compliance.

They do not operate as a universal document checklist saying every project needs exactly:

• X drawings;
• Y calculations.

The information submitted needs to be appropriate to the project and sufficient to demonstrate compliance.

What Does a Full Plans Application Normally Include?

A detailed residential Full Plans package can include:

• existing plans;
• proposed plans;
• elevations;
• sections;
• construction details;
• technical notes;
• structural calculations;
• thermal calculations where relevant;
• drainage information.

The actual requirement depends on the work.

Why Full Plans Benefits From Coordination

Under Full Plans, Building Control assesses the technical information before or during the early stages of construction.

A coordinated package can help identify conflicts between:

• structural design;
• insulation;
• drainage;
• fire protection;
• construction details.

before they become site problems.

What About Building Notice?

A Building Notice does not involve the same formal pre-approval of detailed plans.

However, Building Control can still request additional information.

This may include:

• structural calculations;
• details;
• drawings.

Using a Building Notice does not mean:

“No structural drawings or calculations are ever needed.”

Are Structural Calculations Required With a Building Notice?

They may be.

For example, if the project includes:

• steel beam;
• load-bearing-wall removal;
• structural frame;

Building Control may require calculations to demonstrate structural compliance.

Can I Build From Structural Calculations Alone?

For a very simple project, possibly, if the structural arrangement is clear from other project information.

But for larger projects, calculations alone are usually not enough to explain:

• construction build-ups;
• dimensions;
• insulation;
• fire safety;
• ventilation;
• drainage;
• interfaces between elements.

That is why Building Regulation drawings remain important.

Can I Build From Structural Drawings Alone?

Not safely where the structural adequacy relies on engineering calculations that have not been undertaken.

The drawing and calculation serve different purposes.

What Does the Builder Actually Need?

The builder needs clear construction information.

That can include:

• dimensions;
• opening positions;
• structural member references;
• beam sizes;
• bearing details;
• construction details;
• Building Regulation notes.

The numerical calculation may be less useful day-to-day on site than the drawing, but it underpins the design.

What Does the Steel Fabricator Need?

A fabricator may need:

• exact steel section;
• length;
• steel grade where specified;
• plates;
• holes;
• connection information.

The calculation alone may not provide all fabrication dimensions.

Are Fabrication Drawings the Same as Structural Drawings?

No.

Fabrication drawings or:

shop drawings

are typically prepared for the manufacture of structural steel.

They can show:

• cut lengths;
• holes;
• plates;
• welds;
• bolts;
• fabrication details.

They are downstream from the structural design.

Who Produces Steel Fabrication Drawings?

Usually:

• steel fabricator;
• specialist steel contractor.

The structural designer provides the structural design requirements.

The fabricator then develops the manufacturing information.

Does BuildRegs Produce Steel Fabrication Drawings?

Not as part of a standard structural-calculation service unless specifically included in the agreed scope.

The fabricator typically produces:

• shop drawings;
• fabrication details;

based on the structural design.

What About Temporary Works Drawings?

Temporary works are another separate category.

They can include:

• propping layouts;
• temporary beams;
• needles;
• temporary bracing;
• sequencing.

These are not automatically included within permanent structural drawings/calculations.

Why Is That Important?

If a wall is being removed:

Permanent structural design

might show:

B1 steel beam

but before B1 exists:

Temporary works

must safely support the structure.

The contractor needs to manage that separately.

Structural Calculations vs Method Statement

A structural calculation is not a:

method statement.

A method statement explains:

• how work will be carried out;
• sequence;
• safety arrangements;
• construction process.

The structural calculation establishes the adequacy of the permanent structure within its scope.

Structural Drawing vs Method Statement

Likewise, a structural drawing is not a demolition sequence.

It shows the proposed structural arrangement rather than automatically telling the contractor:

• where to place every prop;
• when to remove masonry;
• how to lift the steel.

Do Structural Drawings Need to Be Signed?

There is no simple universal domestic rule saying every structural drawing must carry one specific signature or professional title.

The important requirements include:

• competence;
• responsibility;
• clear design information.

The person or organisation undertaking structural design should be competent for the work.

Do Structural Calculations Need to Be Signed by a Chartered Engineer?

Not automatically for every ordinary domestic project under the Building Regulations.

The dutyholder framework focuses on competence rather than imposing one professional title for every structural calculation.

However, Building Control may reasonably require sufficient information to identify:

• designer;
• project;
• calculation;
• revision.

More complex structural work may warrant specialist chartered engineering involvement.

What Does Competence Mean?

Current Building Regulations dutyholder requirements place responsibilities on designers.

Designers should possess the necessary:

• skills;
• knowledge;
• experience;
• behaviours

for their work.

They should not undertake work beyond their competence.

Does Preparing Structural Calculations Make Someone the Principal Designer?

No.

Producing structural calculations is a:

designer function.

The Building Regulations Principal Designer is a separate dutyholder role relating to planning, managing, monitoring and coordinating the design work.

A structural designer is not automatically the statutory Principal Designer merely because they prepared calculations.

What If I Have More Than One Designer?

This is common.

For example:

Architectural Designer

Building Regulation drawings.

Structural Designer

Calculations.

Kitchen Designer

Kitchen layout.

Where multiple designers are involved, coordination becomes important.

Who Coordinates the Drawings and Calculations?

The project's design-management arrangements should ensure the information is coordinated.

For Building Regulations dutyholder purposes, where there is more than one designer, the client normally needs to ensure the appropriate Principal Designer appointment is made.

That does not mean every technical drawing provider automatically assumes that role.

What If the Structural Calculations Change?

The associated drawings should be reviewed.

For example:

Original calculation:

B1 = 203 UB

Revised calculation:

B1 = 254 UB

Any drawing showing the old B1 should be updated.

What Causes Structural Calculations to Change?

Changes can include:

• wider opening;
• new wall above;
• altered floor direction;
• different roof design;
• new column;
• changed foundation;
• unexpected site condition.

What Happens If Site Conditions Differ From the Drawings?

Tell the relevant designer before continuing with the affected work.

Examples:

• wall thicker than assumed;
• joists run another direction;
• hidden beam discovered;
• poor masonry;
• unexpected drainage;
• foundation different from design.

The structural design may need to be reviewed.

Can Building Control Ask for Revised Calculations?

Yes.

Building Control may raise technical queries and request:

• clarification;
• additional calculations;
• revised drawings;
• further information.

This is a normal part of technical review.

Does a Building Control Query Mean the Design Is Wrong?

Not necessarily.

Queries can arise because:

• information is missing;
• drawing and calculation differ;
• assumption is unclear;
• more detail is required.

Good coordination makes those queries easier to resolve.

Can I Send Structural Calculations After the Drawings?

Potentially.

But it is generally better to coordinate them before construction where structural work affects:

• beam sizes;
• wall thickness;
• foundations;
• ceiling levels.

Late structural design can force architectural changes.

Should Structural Design Start Before Building Regulation Drawings?

Ideally, the two should develop together where structure materially affects the design.

For example:

A rear opening may determine:

• beam depth;
• column positions;
• ceiling layout.

Those structural decisions can affect the architectural drawings.

Example: Flush Beam

The architectural drawings show:

flat ceiling

with no downstand.

The structural design later produces:

450mm-deep downstand beam.

Now there is a conflict.

If the structural design had been coordinated earlier, alternatives could have been considered before the drawings were finalised.

Example: Steel Column

The structural design requires:

C1

at the end of an opening.

But the architectural plan places:

• kitchen tall unit;
• doorway;

at the same location.

Again, coordination matters.

Example: Foundation

The Building Regulation drawing proposes:

600mm foundation width

but the structural calculation requires:

larger foundation

for a concentrated column load.

The final drawings need to reflect the structural requirement.

Structural Calculations for Extensions

An extension can require calculations for:

• rear-wall opening;
• steel beam;
• roof beam;
• lintels;
• columns;
• foundations;
• unusual roof structure.

The relevant elements should coordinate with the Building Regulation drawings.

Structural Drawings for Extensions

They may show:

• beam layout;
• structural opening;
• column positions;
• foundation arrangement;
• roof structure.

For many domestic extensions, some of this information can be integrated into the main Building Regulation drawing package.

Structural Calculations for Loft Conversions

Common calculations include:

• new floor joists;
• steel beams;
• roof alterations;
• dormer;
• trimmers;
• stair opening;
• columns/connections where relevant.

Structural Drawings for Loft Conversions

The drawings can show:

• B1/B2 beam locations;
• J1 joist direction;
• dormer framing;
• trimmed openings;
• roof changes;
• stair opening.

Structural Calculations for Garage Conversions

Not every garage conversion needs extensive structural calculations.

They become more relevant if the project includes:

• structural wall removal;
• widened opening;
• new beam;
• questionable support for garage-door infill;
• roof alteration.

Structural Drawings for New Builds

New houses generally require a more extensive structural package.

This can include:

• foundation plans;
• floor structure;
• roof structure;
• steelwork;
• lintels;
• details;
• schedules.

Calculations establish the design of those structural systems.

What If I Only Need One Steel Beam?

You may not need a large structural drawing package.

A simple structural-opening service may be sufficient.

For example:

RSJ / Structural Opening Calculations

From £249

The exact documentation is confirmed after the project information is reviewed.

What If I Need a Whole Extension Package?

Then it is often more efficient to obtain:

Building Regulation Drawings

Structural Calculations

as a coordinated package.

This avoids commissioning multiple disconnected services.

What If I Already Have Building Regulation Drawings?

They can be reviewed to establish:

• what structural calculations are still required;
• whether sufficient dimensions are available;
• whether structural references need adding.

There is no need to discard useful drawings simply because another provider is doing the calculations.

What If I Already Have Structural Calculations?

They may be incorporated into the wider technical package if:

• relevant;
• current;
• coordinated with the proposal.

The Building Regulation drawings should reference the actual structural design rather than duplicate or contradict it.

Can Old Structural Calculations Be Reused?

Potentially only if they genuinely remain applicable.

They should be reviewed if:

• design changed;
• opening changed;
• loading changed;
• site conditions differ.

Can Calculations From Another Property Be Used?

No.

Structural calculations are project-specific.

Even similar houses can differ in:

• spans;
• floor direction;
• wall location;
• roof loads;
• previous alterations.

Can Structural Drawings Be Prepared Online?

Yes, for suitable projects where reliable project information is available.

Inputs can include:

• PDF drawings;
• DWG drawings;
• measurements;
• photographs.

Can Structural Calculations Be Prepared Online?

Also yes, for many suitable residential projects.

The determining factor is whether the structural designer has sufficient reliable information to undertake the design competently.

When Is a Site Visit Needed?

A site visit or further investigation may be needed where:

• existing structure is uncertain;
• construction is unusual;
• masonry condition is questionable;
• dimensions cannot be verified;
• previous structural alterations complicate the load path.

Do I Need to Upload a DWG?

Not necessarily.

A clear PDF can often be sufficient.

DWG files can be useful because they allow:

• dimensions;
• geometry;
• drawing development

to be handled more efficiently.

Can I Upload Planning Drawings?

Yes.

Existing planning drawings can be an excellent starting point for:

• Building Regulation drawings;
• structural design.

They should be accurate and reflect the project being built.

What Information Should I Upload?

Useful information includes:

• planning drawings;
• existing plans;
• proposed plans;
• sections;
• elevations;
• dimensions;
• photographs;
• structural information already available;
• Building Control comments if applicable.

What If Building Control Has Already Sent Me Comments?

Upload the comments with the drawings.

They can help identify whether the missing information is:

• structural calculation;
• structural drawing;
• construction detail;
• other Building Regulations information.

This Can Save Time

Instead of guessing what Building Control means by:

“Please provide structural details”

send:

• their comment;
• current drawings.

The required response can then be scoped from the actual request.

How Much Do Structural Drawings Cost?

There is no universal price.

Cost depends on:

• project type;
• number of structural elements;
• level of detail;
• complexity;
• existing information.

For a simple structural opening, a large standalone drawing package may not be required.

How Much Do Structural Calculations Cost?

Again, scope matters.

BuildRegs currently offers:

RSJ / Structural Opening Calculations

From £249

Larger projects involving:

• extensions;
• loft conversions;
• multiple beams;
• frames;
• foundations

are priced according to the complete scope.

What About Building Regulation Drawings and Structural Calculations Together?

For larger residential projects, the combined service can be more efficient because:

• structural references can be integrated into the drawings;
• calculations can match the exact proposed design;
• Building Control receives a more coordinated package.

BuildRegs offers combined technical packages for project types including:

• extensions;
• loft conversions;
• garage conversions;
• other residential work.

Is Building Control Included?

No.

Building Control is a separate regulatory service.

The drawings and calculations are prepared for use in the Building Control process.

The Building Control body independently assesses compliance.

Does a Structural Drawing Guarantee Building Control Approval?

No.

Neither drawings nor calculations can legitimately guarantee approval.

Building Control may:

• assess;
• query;
• request amendments;
• request additional information.

The objective is to provide a well-coordinated technical package that demonstrates the proposed compliance approach.

Do Structural Calculations Guarantee Approval?

No.

They provide structural evidence within their scope.

Building Control still considers:

• structure;
• fire;
• ventilation;
• insulation;
• drainage;
• other relevant requirements.

How BuildRegs Works

Step 1 — Upload Your Existing Information

Send:

• PDF;
• DWG;
• planning drawings;
• sketches;
• photographs;
• Building Control comments.

Step 2 — Scope Review

BuildRegs identifies whether the project appears to require:

• Building Regulation drawings;
• structural calculations;
• both.

Step 3 — Fixed Quote

You receive a fixed quote for the agreed scope.

Step 4 — Technical Design

The drawings and calculations are prepared and coordinated where both form part of the service.

Step 5 — Digital Delivery

The completed technical package is delivered digitally for use in the Building Control process.

Frequently Asked Questions