Contractor Design Services, Drawing & Drafting

The Structure Studio provides specialist contractor design services, technical drawing, and drafting to support contractors, developers, and specialist sub-contractors working on residential and commercial projects.

Whether you need structural drawings for a Building Control submission, detailed construction drawings to take to site, or support with a Contractor’s Designed Portion (CDP), our experienced team of architects and structural engineers can deliver accurate, buildable documentation to keep your project on programme.

We work closely with contractors to understand the practical requirements of each project, producing clear and comprehensive drawings that reduce queries on site and help avoid costly delays.

What Are Contractor Design Services?

On many construction projects, elements of the design are left to the contractor or specialist sub-contractors to complete. This is commonly referred to as the Contractor’s Designed Portion (CDP) under JCT contracts, or simply contractor design under other forms of contract.The contractor takes responsibility for completing the detailed design, producing construction drawings, and ensuring their portion of the works complies with Building Regulations and the employer’s requirements.

This approach allows contractors to bring their practical expertise into the design, often resulting in more buildable and cost-effective solutions. However, it also means the contractor needs access to qualified design professionals who can produce the necessary calculations, drawings, and documentation.

The Structure Studio acts as that design resource, providing contractors with the technical support they need without the overhead of an in-house design team.

If you have any questions about contractor design, view our frequently asked questions or get in touch with one of our team today.

Contractor’s Designed Portion vs. Design and Build

A Contractor’s Designed Portion (CDP) should not be confused with a full Design and Build contract. Under CDP, the contractor is responsible for designing specific parts of the works, while the client’s design team retains responsibility for the overall design. Under Design and Build, the contractor takes on responsibility for the entire design.

How We Work with Contractors

Brief & Review

You send us the project information — employer's requirements, architect's drawings, specifications, and any design responsibility matrix. We review the scope and confirm what's needed, providing a clear fee proposal and programme.

Design & Drawing

Our engineers and technicians produce the structural calculations, construction drawings, and any supporting documentation required. We coordinate with the wider design team and other sub-contractors to ensure everything fits together.

Approval & Site Support

Drawings are submitted for approval by the client’s design team and Building Control. Once approved, we remain available throughout construction to answer queries, issue revisions, and provide site support as needed.

Drawing & Drafting Services

Accurate, detailed drawings are the backbone of any successful construction project. Our drawing and drafting service provides contractors with the documentation they need to build with confidence.

We produce drawings using AutoCAD and Revit, delivering in whatever format your project requires — DWG, PDF, or printed sets.

Our drawing and drafting services include:

Structural general arrangement drawings
Steel fabrication and connection detail drawings
Reinforcement and foundation detail drawings
Construction detail drawings for site
As-built drawings and record documentation
Planning and Building Regulation drawings
Measured surveys and existing condition drawings

Contractor's Designed Portion (CDP) Support

When a JCT contract includes a Contractor’s Designed Portion, the contractor is required to complete the design for specific elements of the works, produce detailed drawings, and ensure compliance with the employer’s requirements and Building Regulations.

The Structure Studio provides the design expertise to fulfil these obligations. We work as an extension of your team, taking responsibility for the structural design, calculations, and drawing production so you can focus on delivery.

Common CDP elements we design include:

Structural steelwork design and connection details
Foundation design
Retaining wall design
Timber frame and roof structure design
Temporary works design
Specialist sub-contractor coordination

Working with Contractors and Developers

We understand that contractors work to tight programmes and budgets. Delays in receiving design information can have a knock-on effect across the entire project, so we prioritise clear communication and reliable turnaround times.

Many of our contractor clients use us as their go-to design resource, sending us drawings at tender stage to help price structural elements accurately, and then engaging us to produce the full construction documentation once the project is won.

Whether you need a one-off beam calculation or a complete set of structural drawings for a multi-unit development, we can scale our service to suit your needs.

Building Regulations and Compliance

All structural design and drawing work we produce is fully compliant with current Building Regulations and relevant British Standards and Eurocodes. Our calculations and drawings are prepared to a standard that satisfies Building Control requirements, helping to avoid delays in the approval process.

We also ensure that our designs coordinate with the wider project, taking account of architectural intent, services routes, and any specialist requirements from other sub-contractors.

Why accurate drawings matter

Poor or incomplete drawings are one of the most common causes of delays and disputes on construction projects. Dimensions that don’t add up, missing details, and drawings that don’t coordinate with other trades all lead to queries from site, rework, and wasted time.

Our drawings are produced by experienced technicians and checked by chartered engineers. Every drawing is reviewed before issue to ensure accuracy, completeness, and buildability.

Getting it right first time

Getting professional design support early in a project — ideally at tender stage — helps contractors price accurately, identify potential issues before they become problems on site, and demonstrate competence to clients and main contractors.

Get in touch

If you are a contractor or developer looking for reliable design and drawing support, our team can help. We have extensive experience working with contractors of all sizes, from small builders through to national developers and specialist sub-contractors.

Send us your project details and we will provide a fee proposal and programme, typically within 24 hours.