New Build Structural Calculations and Building Regulation Drawings: Complete Guide

Part C — Site Preparation and Moisture

Part C can affect:

contaminants;

ground preparation;

moisture resistance;

floors;

walls;

roofs.

Damp-Proofing

The design should coordinate:

DPC;

DPM;

cavity trays;

external ground levels;

floor construction.

Radon and Ground Gases

Some sites may require protective measures against:

radon;

methane;

other ground gases.

Site-specific information should be checked where applicable.

Part E — Resistance to Sound

Part E covers resistance to the passage of sound in dwellings.

For a detached house, internal acoustic design can still apply between certain spaces.

For:

semi-detached houses;

terraces;

flats;

separating walls and floors become especially important.

Separating Structures

Where two dwellings adjoin, the design may need to address:

separating walls;

separating floors;

flanking transmission.

Testing requirements can also apply depending on the development and construction route.

Part F — Ventilation

A new dwelling requires a properly designed ventilation strategy.

This is more than:

“put an extractor fan in the bathroom.”

The design needs to address:

whole-dwelling ventilation;

extract ventilation;

supply/background air;

purge ventilation;

system commissioning.

Common Ventilation Systems

Depending on the design:

Natural / Background Ventilation + Extract

or:

Continuous Mechanical Extract

or:

Mechanical Ventilation With Heat Recovery

The appropriate solution depends on the project.

Airtightness and Ventilation Must Be Designed Together

A highly airtight house without adequate ventilation can create:

poor air quality;

excess humidity;

condensation.

The ventilation system must suit the actual fabric strategy.

Important Future Homes Standard Timing

The government published:

Approved Document F 2026

and:

Approved Document L 2026

on 24 March 2026.

For ordinary non-higher-risk work, the associated regulatory changes generally come into force on:

24 March 2027.

Transitional Arrangements

Where the relevant:

Building Notice;

Initial Notice;

application for Building Control approval with Full Plans

is given before:

24 March 2027

and the relevant work is commenced before:

24 March 2028,

the earlier standards can continue to apply under the transition.

The applicable standard therefore needs to be established from:

submission date;

commencement date.

Why This Is Especially Important for New Builds in 2026–2028

A new-build project can have a long:

planning;

technical-design;

procurement

period.

A house being designed in 2026 may be constructed under a different energy/ventilation standard depending on when the relevant Building Control application and commencement occur.

Do not rely on old U-value tables without establishing:

which regulatory regime actually applies.

Part L — Energy Performance

Part L is fundamental to new dwelling design.

Unlike an ordinary extension, new houses are assessed using a:

whole-dwelling energy-performance approach.

The design needs to coordinate:

fabric;

glazing;

airtightness;

heating;

hot water;

ventilation;

renewable technology where applicable.

Energy Calculations

A specialist energy assessment may be required to demonstrate compliance.

The technical package must therefore coordinate with the:

energy model;

architectural design;

construction specification.

Do Building Regulation Drawings Replace Energy Calculations?

No.

The drawings show the construction specification.

The energy assessment demonstrates the dwelling's calculated performance.

They need to agree.

Don't Change Insulation Products Without Checking

Changing:

thickness;

manufacturer;

conductivity;

wall build-up

can alter thermal performance.

A site substitution should be checked against the technical and energy design.

Airtightness

Airtightness is a critical new-build performance issue.

Details at:

windows;

doors;

floor/wall junctions;

roof/wall junctions;

service penetrations

need coordination.

Thermal Bridging

Junction design can materially affect:

heat loss;

condensation risk;

calculated energy performance.

Do not treat thermal bridges as an afterthought.

Part O — Overheating

This is one of the major differences between a new house and an extension.

Part O:

applies to new residential buildings.

It specifically aims to reduce overheating risk.

Does Part O Apply to a New House?

Yes.

Unlike an extension to an existing house, a newly erected dwelling falls within Part O's scope.

Overheating Design Can Affect Architecture

The assessment can influence:

window size;

orientation;

shading;

openable areas;

glazing specification.

This needs consideration early.

Huge South-Facing Glazing Can Create Problems

A planning design with:

extensive glass;

limited shading

may need modification to satisfy overheating requirements.

This is another reason not to treat Building Regulations as a paperwork exercise after planning.

Part G — Water Efficiency

New dwellings need to satisfy water-efficiency requirements.

Under the current standard, estimated wholesome-water consumption is generally limited to:

125 litres per person per day.

Where the optional requirement is imposed through planning:

110 litres per person per day

may apply.

Check the Planning Permission

The optional water-efficiency requirement can be triggered through planning.

The technical design should therefore review:

decision notice;

planning conditions.

Water Efficiency Is Not Just a Drawing Note

Compliance can depend on actual:

WC flush volumes;

shower flow rates;

taps;

baths;

appliances.

The selected fittings need to align with the calculation/specification.

Part H — Drainage

New-build drainage needs to be designed as a complete system.

This can include:

foul drainage;

rainwater drainage;

inspection chambers;

below-ground pipes;

connections.

Foul Drainage

The design should establish:

stack positions;

pipe routes;

gradients;

chambers;

final connection.

Surface Water

Rainwater may be dealt with through:

soakaways;

infiltration systems;

other approved drainage strategies.

The appropriate solution depends on site conditions.

Soakaways Are Not Automatically Suitable Everywhere

The site may require:

infiltration testing;

alternative drainage.

Drainage design should respond to the ground.

Drainage Should Be Designed Before Foundations Are Built

Foundation and drainage drawings should be coordinated to avoid:

pipes through pad foundations;

inaccessible chambers;

structural conflicts.

Part K — Stairs and Guarding

New houses need compliant:

stairs;

landings;

guarding;

protection from falling.

The stair should be resolved early because it affects:

floor openings;

headroom;

structural trimmers;

circulation.

Stair Design Affects Structure

A stair opening interrupts the floor.

The structural design may require:

trimmers;

doubled joists;

beams.

The architectural stair and structural floor cannot be designed independently.

Part M — Access to New Dwellings

Part M Volume 1 applies to newly erected dwellings.

The baseline is:

M4(1) — Category 1: Visitable Dwellings.

M4(2) and M4(3)

Planning permission can impose higher optional standards:

M4(2)

Accessible and adaptable dwelling.

M4(3)

Wheelchair-user dwelling.

Where imposed, these become important technical-design requirements.

Why the Planning Conditions Must Be Reviewed Before Technical Design

A planning condition requiring:

M4(2)

can affect:

approach;

entrance;

door widths;

circulation;

WC;

bedroom/bathroom arrangements.

Discovering it after the floor plans have been frozen can cause major redesign.

Part Q — Security

Part Q applies specifically to:

new dwellings.

It requires reasonable provision to resist unauthorised access.

This affects:

doors;

windows;

hardware.

Don't Leave Security Specification to the End

The window and door schedules should be compatible with the Part Q requirements before procurement.

Part R — Electronic Communications

New homes are subject to requirements for:

gigabit-ready physical infrastructure

and:

connection to a gigabit-capable network,

subject to the applicable provisions and exceptions.

Connectivity Is Now Part of Building Regulations Design

The project may therefore need to consider:

ducts;

termination points;

service entry;

connectivity plan.

Part S — Electric Vehicle Charging

Part S can apply to new residential buildings with associated parking.

For a typical new detached dwelling with parking, this can mean provision of:

an EV charge point.

For example, current government guidance confirms that a new detached house with two associated parking spaces would normally require one charge point.

Coordinate EV Charging Early

The design should consider:

parking position;

charge-point location;

electrical supply;

cable route.

Do not treat it as something to add after landscaping.

Part P — Electrical Safety

Electrical installations within the new dwelling must comply with Part P.

This includes:

power;

lighting;

circuits;

consumer unit;

relevant fixed installations.

Appropriate inspection/testing/certification should form part of the completion information.

Heating and Hot Water

The new house needs a coordinated heating and hot-water strategy.

This can involve:

heat pump;

boiler where permitted/applicable;

hot-water cylinder;

underfloor heating;

radiators;

controls.

The services strategy interacts strongly with Part L.

Services Need Space

Technical drawings should allow for:

plant;

cylinders;

ventilation units;

ducts;

soil stacks;

distribution pipework.

A services cupboard cannot be designed after every centimetre of the floor plan has already been allocated.

MVHR and Duct Routes

Where mechanical ventilation with heat recovery is proposed, the designer should consider:

unit location;

ducts;

ceiling zones;

external terminals.

Structural beams can obstruct ducts.

The two need coordination.

Structure vs Services

Common clashes include:

Beam

vs

MVHR duct.

Floor joist

vs

soil pipe.

Foundation

vs

drain.

Steel column

vs

kitchen unit.

The technical package should find these before construction.

Building Regulation Drawings for a New House

A suitable drawing package might include:

Site / Ground Floor Information

site plan;

foundation plan;

drainage plan.

General Arrangement

ground-floor plan;

upper-floor plans;

roof plan.

Sections

main building section;

staircase;

floor/wall/roof relationships.

Elevations

Where relevant for technical coordination.

Construction Details

foundation/wall;

floor/wall;

wall/roof;

eaves;

openings;

DPC/DPM;

insulation;

airtightness.

Technical Notes

fire;

ventilation;

energy;

drainage;

access;

safety.

The exact deliverables should reflect the actual design.

Structural Drawings for a New House

These may include:

foundation layout;

beam layout;

floor structure;

columns;

roof structure;

structural details;

references matching calculations.

Structural Drawings vs Structural Calculations

Structural Drawing

shows:

where it goes.

Structural Calculation

shows:

why it is adequate.

A new house can require both.

Example

Drawing:

B1 between Grid A and Grid B.

Calculation:

B1 designed for the loads, span, reactions and serviceability requirements.

New Build Foundation Plan

The foundation drawing should coordinate:

load-bearing walls;

columns;

pad foundations;

drainage;

service penetrations.

Don't Design Foundations From the Ground-Floor Plan Alone

The foundation designer also needs to understand:

what happens above.

A seemingly ordinary ground-floor wall may carry:

upper wall;

floor;

roof.

Building Control Route

For an ordinary single new house that is not a higher-risk building, Building Control is generally provided through:

local-authority Building Control;

registered building control approver.

Full Plans

For a new house, a properly developed technical-design package is normally the sensible basis for Building Control.

Current government guidance gives the normal Full Plans determination period as:

5 weeks

or:

2 months with consent.

Building Notice for a New House?

Government currently describes Building Notice as a route for:

smaller projects.

In April 2026, government consulted on requiring all new dwellings using the local-authority route to use Full Plans.

That consultation is not itself the law.

However, even without that proposed change:

a new house should be fully technically designed before construction.

Do Not Treat the Building Notice Route as a Way to Avoid Plans

A new dwelling involves too many coordinated requirements to sensibly rely on:

“we'll resolve it on site.”

Higher-Risk Buildings

Most individual houses are not higher-risk buildings.

The separate BSR Building Control regime generally applies where a building is at least:

18m high; or

7 storeys;

and contains at least:

2 residential units,

or falls into certain hospital/care-home categories.

A typical detached new house therefore does not fall within that higher-risk regime.

Building Safety Levy — Important From 1 October 2026

A major new issue for residential development begins on:

1 October 2026.

The Building Safety Levy applies to certain developments creating new residential floorspace in England.

Applications for Building Control approval made on or after that date for new dwellings may need:

levy information;

assessment of liability or exemption;

payment where chargeable.

Does Every Self-Build Automatically Pay the Levy?

Do not assume either way.

The regulations contain:

exemptions;

charging conditions.

The project's actual status should be checked against the current Building Safety Levy rules.

Why This Matters Now

A new-house Building Control application submitted:

30 September 2026

and one submitted:

1 October 2026

can potentially sit on different sides of the new levy commencement date.

This is a regulatory issue worth checking before submission.

The Levy Is Separate From Building Control Fees

Potential project costs can include:

Building Control fee;

Building Safety Levy where applicable;

professional design fees;

specialist reports.

They should not be confused with each other.

Building Regulations Dutyholders

The Building Regulations dutyholder regime applies to building work in England.

Dutyholders can include:

client;

designers;

Principal Designer;

contractors;

Principal Contractor.

New Builds Usually Involve Multiple Designers

For example:

architectural designer;

structural designer;

energy assessor;

ventilation designer;

drainage designer.

Where more than one designer is involved:

design coordination becomes critical.

Principal Designer

The Building Regulations Principal Designer has responsibilities relating to:

planning;

managing;

monitoring;

coordinating

the design work so far as it relates to Building Regulations compliance.

Does the Structural Engineer Automatically Become Principal Designer?

No.

Providing structural calculations does not automatically constitute appointment as the project's Building Regulations Principal Designer.

Does BuildRegs Automatically Become Principal Designer?

No.

Providing Building Regulation drawings and structural calculations does not automatically mean BuildRegs has accepted the statutory Principal Designer role.

Any such appointment would need to be expressly agreed within the professional scope.

Building Regulations Principal Designer vs CDM Principal Designer

These are distinct legal roles.

A project may have obligations under:

Building Regulations;

CDM 2015.

Do not assume one appointment automatically satisfies the other.

Building Control Does Not Coordinate the Design for You

Building Control assesses compliance.

It does not become the project's:

architect;

structural designer;

Principal Designer;

services designer.

The design team remains responsible for producing coordinated technical information.

Specialist Information That May Be Needed

A new house may also require specialist input beyond drawings and basic structural calculations.

Depending on the scheme:

energy calculation;

overheating assessment;

ventilation design;

air-permeability test;

sound testing;

drainage design;

geotechnical information;

truss design;

electrical certification;

commissioning data.

One Consultant Does Not Necessarily Produce Every Specialist Document

The project scope should clearly identify:

who is producing what.

Building Regulations Drawings Are the Coordination Document

The architectural technical set often becomes the place where information from:

structural engineer;

energy assessor;

ventilation designer;

drainage design;

product manufacturers

is coordinated.

Current Drawing Revisions Matter

A new-build project can change repeatedly.

Always identify:

latest planning drawing;

latest technical drawing;

latest structural calculation.

Do not build from a superseded set.

Document Control

A useful system may include:

P01

Preliminary.

P02

Revised technical.

C01

Construction issue.

The exact convention can differ.

The important thing is that everybody knows:

which design is current.

When Should Structural Calculations Be Prepared?

During the:

technical-design stage.

Not after foundations are already being excavated.

When Should Energy Calculations Be Done?

Early enough that they can influence:

insulation;

glazing;

services;

airtightness.

Do not wait until the building is complete to discover the designed specification does not satisfy the model.

When Should Overheating Be Assessed?

Early.

Part O can influence:

window sizes;

orientation;

shading.

Late assessment can cause redesign.

When Should Drainage Be Designed?

Before:

foundations;

slab;

landscaping.

The Right Design Sequence

A strong workflow is:

1. Planning Design

↓

2. Planning Approval and Conditions Review

↓

3. Technical Geometry Confirmed

↓

4. Structural Design

↔

5. Energy / Ventilation / Overheating

↔

6. Drainage and Services

↓

7. Building Regulation Drawings Coordinated

↓

8. Building Control Submission

↓

9. Technical Comments Resolved

↓

10. Construction Information Finalised

↓

11. Builder Pricing / Procurement

↓

12. Construction and Inspection

Why Coordination Happens in Both Directions

Suppose the structural designer needs:

C1 column.

That alters:

room layout.

The architectural drawing changes.

That could alter:

energy model.

A duct route might then need adjustment.

Technical design is iterative.

Common New-Build Technical Mistakes

1. Treating Planning Drawings as Construction Drawings

Planning approval does not establish technical compliance.

2. Designing Foundations Without Ground Information

Foundation design needs a reliable basis.

3. Freezing Architecture Before Checking Structure

This can create avoidable transfer beams and columns.

4. Doing SAP/Energy Work Too Late

Energy performance can affect the fabric and services.

5. Ignoring Part O Until the End

Glazing may need redesign.

6. Forgetting Part M Planning Conditions

M4(2) or M4(3) can materially affect layouts.

7. Failing to Coordinate Drains With Foundations

A classic site conflict.

8. Ordering Trusses Before Rooflights Are Final

Openings and structure need coordination.

9. Letting Different Consultants Use Different Drawing Revisions

This creates contradictory information.

10. Assuming Building Control Will Design Missing Details

They will not.

Builder Pricing Should Follow Technical Design

A planning drawing might say:

“New 4-bedroom house.”

A contractor still has to guess:

foundation system;

steelwork;

insulation;

roof;

ventilation;

drainage.

That produces uncertain quotes.

Better Tender Information Creates Better Pricing

Once the technical package identifies:

foundation arrangement;

structural steel;

wall specification;

floor system;

roof build-up;

thermal specification;

builders can price a more defined project.

Design First. Price Second.

That is particularly important on a new house where even small specification differences can materially affect construction cost.

What Information Does BuildRegs Need?

For an initial new-build review, useful information includes:

planning-approved drawings;

proposed plans;

elevations;

sections;

site plan;

planning decision;

planning conditions;

PDFs;

DWGs where available.

Additional Information

Where available:

ground investigation;

drainage information;

levels;

energy strategy;

tree information;

Building Control comments;

previous technical design.

Don't Wait Until You Have Everything

Upload what you already have.

The scope review can identify which specialist information is still required.

Can BuildRegs Work From Another Architect's Planning Drawings?

For suitable projects:

yes.

Existing architectural information can often form the basis of the Building Regulation technical stage, subject to appropriate rights to use it.

Can BuildRegs Prepare the Structural Calculations?

For suitable residential new-build projects, structural calculations can be included within the agreed technical scope.

Can BuildRegs Prepare Building Regulation Drawings?

Yes, for suitable residential projects.

Is Every New Build Suitable for a Standard Fixed Package?

No.

A new build is one project type where the fee should reflect the actual technical scope.

Compare:

Simple Detached House

conventional masonry;

simple roof;

straightforward ground;

limited steel.

with:

Complex Contemporary House

large cantilevers;

huge glazing;

multiple frames;

transfer structure;

complex foundations;

unusual roof;

extensive bespoke details.

They should not be treated as the same product.

New Build Pricing

BuildRegs reviews new-build projects individually before confirming the fixed quotation.

The quote should reflect the agreed scope, which may include:

Building Regulation drawings;

structural calculations;

level of structural complexity;

available information.

Why Individual Quoting Is Better

It prevents:

simple clients subsidising complex work;

complex projects being under-scoped;

unclear expectations about specialist services.

Is the Building Control Fee Included?

No, unless expressly included in the agreed quotation.

Building Control charges are separate.

Is Planning Included?

No, unless separately agreed.

This service relates to the:

technical Building Regulations stage.

Are SAP / Energy Calculations Included?

Only if expressly included in the agreed scope.

The quotation should identify specialist services clearly rather than implying everything required for a new home is automatically included.

Is an Overheating Assessment Included?

Only where expressly included.

Part O assessment may require specialist analysis depending on the adopted compliance route.

Is Drainage Design Included?

The Building Regulation drawings may coordinate drainage information within the agreed scope, but specialist:

civil drainage;

SuDS;

flood;

infiltration

work should be clearly identified where required.

Are Truss Calculations Included?

Proprietary truss design is commonly provided by the truss manufacturer.

It should then be coordinated with the main technical package.

Are Temporary Works Included?

Not automatically.

Temporary works relate to construction sequence and should be separately designed where necessary.

How Long Does a New-Build Technical Package Take?

A new house should not automatically be marketed with the same turnaround as:

one RSJ calculation.

The programme depends on:

completeness of drawings;

structural complexity;

specialist coordination;

revisions;

site information.

A project-specific programme should be confirmed after review.

Can a New-Build Package Be Prepared Online?

For suitable projects:

much of the technical design and coordination can be delivered remotely.

The project can be developed from:

drawings;

site information;

photographs;

reports;

digital correspondence.

However, new-build projects can require:

surveys;

ground investigation;

site-specific specialist information

that cannot be replaced by online assumptions.

Building Control Inspections

Technical approval is only one part of the process.

Construction also needs to be inspected at the required stages.

Possible inspection points include:

commencement;

excavation;

foundations;

drainage;

ground floor;

structural work;

insulation;

roof;

completion.

The actual inspection schedule is set by the Building Control body.

Do Not Cover Work Before Required Inspection

Examples can include:

drains;

reinforcement;

insulation;

structural connections.

Follow the project's Building Control inspection requirements.

Changes During Construction

If the builder changes:

foundation;

beam;

insulation;

roof;

window;

ventilation system;

the change may affect:

calculations;

Building Regulations compliance;

Building Control information.

“Equivalent” Products Are Not Always Equivalent

Different insulation products can have:

different conductivity;

different thickness requirements;

different cavity requirements.

Different structural products can have different capacities.

Changes should be technically checked.

Completion Information

Before Building Control completion, the project may need relevant:

certificates;

test results;

commissioning information;

calculations;

declarations;

as-built information.

Completion Certificate

The Building Control completion certificate provides important evidence that the Building Control process has been satisfactorily completed.

This can matter for:

sale;

mortgage;

records;

future alterations.

Frequently Asked Questions