Florence Street, Hitchin
Single-storey rear extension.
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Hampshire Build is an architectural design practice serving Hertfordshire from St Albans. Our work spans home extensions, loft conversions and planning support, with each proposal shaped around the property and its planning context.
With more than 20 years' experience and a 95% planning approval rate, we help homeowners consider the right next step. Our fixed-fee design packages start from £1,950 + VAT; the scope and planning route depend on the home, its location and the proposed work.
Office: Suite 14, STANTA Business Centre, St Albans AL3 6PF
Phone: 01722 548911
Contact our St Albans office to discuss your project.
Single and two-storey extensions
From £1,950 + VAT
Bedrooms, offices and living spaces
From £1,950 + VAT
Expert council navigation
From £1,950 + VAT
A county of varied settings
From our St Albans office, we provide architectural design for Harpenden homes as well as projects across the county. Hertfordshire includes historic market towns, planned Garden City streets, post-war estates and rural villages. Those settings call for different responses: roof form and materials can matter in established streets, while access, neighbour relationships and the existing plot shape can be central to a newer estate.
Planning designations, permitted development rights and local policies vary by address and proposal. We check the relevant council guidance and property constraints before settling on a route; no single approach applies across the county.
Click on your town to learn about local planning requirements and how we can help with your project.
Historic cathedral city with 28 conservation areas
New Town heritage with unique design opportunities
Excellent London links, high property values
Clear permitted development guidelines
Garden City architectural heritage
Medieval character, sensitive design approach
Hertfordshire-Essex border expertise
Conservation area and listed building specialists
Premium residential area, village character
County town with rich architectural heritage
£1,950 + VAT
£2,950 + VAT
£3,950 + VAT
Hampshire Build provides extension design services across 8 counties in South England. Explore our other locations:
Our St Albans office serves extension and conversion projects across Hertfordshire. St Albans and Harpenden use St Albans City & District Council; Hemel Hempstead and Berkhamsted use Dacorum; Watford uses Watford Borough Council; Welwyn Garden City uses Welwyn Hatfield.
Check current the relevant district or borough council planning guidance
Meet our St Albans architectural design practice and see local projects
Pre-Build from £1,950 + VAT; Premium £2,950 + VAT; Premium Plus £3,950 + VAT. Compare the existing package scope. Building work and statutory fees are separate. Structural calculations are prepared by an independent qualified structural engineer.
A single-storey rear extension may qualify for permitted development up to 4 metres for a detached house or 3 metres for other houses, subject to all the rules. Larger home extensions may extend up to 8 metres or 6 metres respectively through the prior approval process. These are the limits described in our permitted development guide, not automatic permission for any property. Check the relevant district or borough council's guidance and the property's planning history.
Conservation areas and Article 4 Directions can remove some permitted development rights. Householder planning is normally dealt with by the district or borough, rather than the county council. Confirm the authority for the address and check heritage designations, planning history, Article 4 Directions and any separate estate controls. A lawful development certificate can provide evidence that qualifying works are lawful. Listed-building consent and other approvals may still be needed.
Our fixed-fee design packages are Pre-Build from £1,950 + VAT, Premium £2,950 + VAT and Premium Plus £3,950 + VAT. Building work and statutory fees are separate. Use the free feasibility study for an indicative project-specific cost check.
Building regulation drawings are prepared for Building Notice submission. The Pre-Build and Premium packages do not include that submission; Premium Plus does, with the council fee excluded. Building Control determines compliance. Structural calculations are prepared by an independent qualified structural engineer.
Councils aim to decide householder applications within 8 weeks of validation. Timing is set by the council and is not guaranteed.
Public council planning decisions
Updated 10 October 2026
In the 12 months to 10 October 2026, The local planning authorities decided 1130 householder home-improvement applications near St Albans, Harpenden, Stevenage, Watford, Hemel Hempstead, Welwyn Garden City, Hitchin, Bishop’s Stortford, Berkhamsted, Hertford in Hertfordshire in the cached public records — 1005 approved.
Single-storey rear extension.
Two-storey rear extension.
Two-storey rear extension; Loft conversion; Porch works.
Two-storey side and rear extension.
Two-storey front extension; Garage conversion.
Single-storey side extension.
Two-storey front and side extension; Porch works.
Single-storey rear extension; Garage conversion.
These are public council decisions about other people’s applications. They are not Hampshire Build projects and do not predict the outcome of your project.