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Serving Portsmouth & Surrounding Areas

Extension Designer Portsmouth

Professional extension design and planning drawings for Portsmouth homeowners. We create detailed plans for single-storey, double-storey extensions and loft conversions - all at a fixed fee with no hidden costs.

Whether you're looking to add a kitchen extension, create a home office, or build additional bedrooms, our experienced team understands Portsmouth's unique planning requirements and architectural character.

Why Choose Hampshire Build in Portsmouth?

  • Fixed-fee packages - no hidden costs
  • Local knowledge of Portsmouth City Council requirements
  • Complimentary initial consultation
  • Clear process and next steps
  • Building regulation drawings prepared for Building Notice submission; structural calculations by an independent qualified structural engineer are included in our packages

Starting from

£1,950 + VAT

Fixed-fee Pre-Build Package

Hampshire homes, considered individually

Planning and design for your Portsmouth home

Homes and projects in the area

Portsmouth and Southsea have many Victorian and Edwardian terraces, compact urban plots and later family houses with different opportunities for extra space.

Rear and side-return extensions can open up a kitchen and dining area. Loft conversions can add a bedroom or workspace while making use of the existing roof volume.

Working with Portsmouth City Council

We pay particular attention to neighbouring windows, garden depth and the relationship with adjoining homes. Heritage character informs designs in historic parts of the city.

Visit Portsmouth City Council

Fixed-fee packages from £1,950 + VAT. Start with a free feasibility study, or book a complimentary consultation to talk through your plans.

Extension Design Services in Portsmouth

Kitchen Extensions

Open-plan living spaces

Two-Storey Extensions

Maximise your space

Loft Conversions

Extra bedrooms & offices

Garden Rooms

Home offices & studios

Single-Storey Extensions

Ground floor expansions

Wrap-Around Extensions

L-shaped & rear-side

Our Fixed-Fee Packages

Choose the package that suits your project. All packages include our complimentary initial consultation.

Pre-Build Package

£1,950 + VAT

Professional on-site measured survey; planning drawings and application; building regulation drawings; independent qualified structural engineer calculations.

Most Popular

Premium Package

£2,950 + VAT

Everything in Pre-Build Package, plus: detailed schedule of works; contractor vetting and two proposals; client-focused building contract.

Premium Plus Package

£3,950 + VAT

Everything in Premium Package, plus: staged programme mapped to contractor payments; Building Notice submission; one Party Wall notice to one adjoining owner.

Helpful Resources

Free Feasibility Study Our Packages Our Portfolio Extension Guides

Also serving: Winchester • Basingstoke • Southampton • Salisbury • Andover • Fareham

Ready to Start Your Portsmouth Extension Project?

Book your complimentary 30-minute consultation with Mark Eden to discuss your extension plans.

Call 01722 548911