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Structural Calculations for Domestic Extensions

Extending your home is an excellent way to create additional living space, whether for a larger kitchen, extra bedrooms, or an open-plan layout. At Loft Designs, we provide precise structural calculations for domestic extensions, ensuring your project is safe, compliant with building regulations, and structurally sound.

Accurate planning is essential for a successful extension. Our structural calculations cover critical elements such as steel beam designs, load-bearing assessments, and foundation checks—helping you meet building regulations while ensuring stability and durability.

Image by Brett Jordan

Steel Beam Calculations for Extensions

Many home extensions require steel beams to support new or modified load-bearing walls, floors, and roof structures. If large sections of masonry are removed, additional steel supports may be needed for lateral stability. Our calculations ensure the correct beam sizes and placements for a safe and compliant extension

Load-Bearing Walls & Foundation Assessments

Building Control often requires verification of new or existing walls, piers, and foundations supporting steel beams. We assess these structural elements to ensure they can handle the additional loads introduced by your extension.

How We Work

Simply email us a PDF copy of your architectural plans, measured survey sketches (in a recognised scale), or AutoCAD drawings. Our team will review your project and provide a competitive quote for bespoke beam calculations tailored to your extension.

Domestic Loft Structural Calcs

from

£600

Dormer Loft Structural Calcs

from

£600

Bespoke Loft Structural Design

from

£POA

Single Beam Design

only

£95

Home Renovation Structural Calcs

from

£POA

Extension  Structural Calcs

from

£POA

*Prices are for guidance only. Final cost depends on the scope of work, site size, and location.

Structural Calculations for Loft Conversions, Extensions & New Builds

Loft Conversion

Loft Conversion Structural Calculations

 

Our loft conversion structural calculation packages include everything needed for Building Control approval, material ordering, and builder reference. Simply provide architectural plans or a measured survey, and we’ll handle the rest.

Our calculation pack includes:

  • Steel beam calculations for loft extensions and roof support, including padstone/bearing plates, splice calculations, and fabrication details

  • Floor joist calculations, including trimming joists

  • Rafter and roof modification calculations

Home Extension

Structural Calculations for Home Extensions

A home extension is a great way to add space—whether it’s a larger kitchen, additional bedrooms, or an open-plan living area. Our team provides precise structural calculations for extensions, ensuring compliance with Building Control regulations.

We offer:

  • Steel beam calculations for single and double-storey extensions

  • Load-bearing wall assessments and modifications

  • Foundation and floor structure calculations

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New Build Structural Calculation Packages

For new build dwellings, we offer comprehensive structural calculation packs to support your Building Control approval. All we need is your architectural plans and Phase 2 site investigation report.

 

Our full new build calculation packages include:

  • Foundation calculations

  • Masonry or timber-framed wall calculations

  • Floor calculations

  • Roof calculations

We deliver reliable solutions for residential loft conversions, attic conversions, home extensions, and internal alterations

Structural Calculations Suitable for Part A Building Regulation Submissions

Download Loft Design's sample structural calculations report suitable for building control

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40+

Backed by over 40 years of structural engineering experience

50+

Team members enabling engineering across the UK

1000+

Residential, commercial & industrial projects nationwide

1

quick and easy online structural calculations service

What Our Clients Say

A Fair Price

Always helpful, punctual delivery of designs & at a fair price. A pleasure to be associated with Loft Designs.

Brooks Building Plans

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Helpful and Efficient

Loft Designs have been working on my projects for over 8 years, they are extremely helpful and efficient in finding cost effective structural solutions to my architectural projects.

Tony Angeletta Architect

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Cannot Fault their Service

I have worked with Loft Designs for a couple of years now and cannot fault their service. They are always happy to help and I look forward to working with them going forward.

Steven C.

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This is a very reliable & professional…

This is a very reliable & professional company with excellent service and very prompt in providing assistance !

L.Bin

Rating

Loft Designs A+

I have used Loft Designs on many projects and on each time they have delivered both in quality and costs. They always happy to help with any queries. I would highly recommend.

Bobyas

Rating

Professional & Knowledgeable

I couldn't be more happy with the service received from Loft Designs. From start to finish, their team was professional, knowledgeable, and attentive to every detail.

Mr. J. Snitzer

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Practical, Cost-Effective

Finding a structural engineer who truly understands the needs of our community isn’t easy, but Loft Designs does exactly that. Their experience with local properties and commitment to delivering practical, cost-effective solutions makes them the go-to choice for structural design.

S. Oppenheimer

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Smooth & Stress-free

After researching several companies for our loft conversion project, we decided to go with Loft Designs, and we're so glad we did. Their expertise in structural engineering and their solutions made the entire process smooth and stress-free. 

M.Reece

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Incredibly Easy

Loft Designs made the experience of a loft conversion less stressful. They provided a design which ensured it was structurally sound and compliant with all regulations.

T.Syed

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Start Your Loft Conversion with Confidence

Join hundreds of homeowners and builders who trust Loft Designs for accurate, Building Control-ready structural calculations - designed specifically for loft conversions.

Frequently Asked Questions

  • How do I know if my property is suitable for a loft conversion?
    Determining the suitability of your property for a loft conversion involves several factors: roof space, roof structure, planning permissions, building regulations, access, budget and timeframes. Loft Designs are loft conversion specialists who can provide professional advice tailored to your specific property and requirements.
  • Do I need planning permission for a loft conversion?
    In many cases, loft conversions in the UK can be carried out under permitted development rights, which means planning permission may not be required. Homeowners in England can often proceed with a loft conversion without the need for planning permission, as long as certain criteria are met.
  • What structural changes are involved in a loft conversion?
    A loft conversion typically involves several structural changes to transform the unused attic space into a functional living area. This can include (but is not limited to): Roof Structure Modification, Floor Reinforcement, Staircase Installation, Window and Door Openings, Insulation and Ventilation, Electrical and Plumbing Work and Structural Integrity. Our team may need to assess load-bearing walls, beams, and foundations, and to design appropriate structural modifications as needed.
  • How can Loft Designs help me with my loft conversion?
    Loft Designs provides expert loft conversion solutions. Our team of structural engineers provide comprehensive structural calculations for your loft conversion project, ensuring safety and compliance every step of the way.
  • Will my loft conversion comply with building regulations?
    Ensuring that your loft conversion complies with building regulations is crucial for safety, structural integrity, and legal compliance. Building regulations require that any structural alterations or additions, such as roof modifications and floor reinforcement, meet specified standards for strength, stability, and load-bearing capacity. Loft Designs provide structural calculations and designs to ensure compliance.
  • How much does Loft Designs service cost?
    Loft Designs provides cost-effective structural calculations for your loft conversion project. Prices start from £600.
  • How can I contact your team?
    Loft Designs is a web-based, online service. To contact a member of our team, please use the website contact form. Alternatively, email info@loft-designs.co.uk and we will get back to you as quickly as possible.
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