
Design, Planning & Build for Datchworth Properties
Extending your home in Datchworth is one of the smartest investments you can make. Our architects and project managers guide you through the full process — from feasibility and design to Hertfordshire County Council approvals and construction oversight — so nothing is left to chance.
Working across Datchworth and the surrounding East Hertfordshire neighbourhoods, we bring local insight that makes a tangible difference to planning outcomes. We know which design approaches tend to succeed here and can advise on realistic budgets from day one.

A recent extension project in the East Hertfordshire area
Local knowledge is not just a nice-to-have — it directly affects whether your Datchworth extension gets approved and how smoothly the build runs. We have invested years building expertise in the East Hertfordshire area, understanding everything from conservation zone boundaries to common ground conditions.
Our architects know how to design extensions that sit comfortably alongside the existing housing stock in Datchworth, and our planning team knows how to present proposals to Hertfordshire County Council in the strongest possible light.
Many extensions in Datchworth can proceed under permitted development rights without a formal planning application — but this depends on your property type, location, and the scale of the proposed works. We assess this during our free consultation and advise on the simplest route to approval.
Where a full application is needed, our planning team prepares all drawings, design and access statements, and supporting documentation for submission to Hertfordshire County Council. We manage the process from start to finish, including responding to officer queries and negotiating amendments if required.
Datchworth has a diverse housing stock and we have experience extending all property types in the area. Our architects adapt designs to suit the character and structure of each home, whether that means matching original brickwork on a period property or creating a contemporary contrast on a more modern home.
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Covering SG3 & surrounding postcodes
Guide prices for house extensions in the East Hertfordshire area. Every project is different — we provide a detailed, itemised quote after a free site visit.
| Extension Type | Typical Cost |
|---|---|
| Single Storey Rear Extension | £30k – £60k |
| Double Storey Extension | £47k – £102k |
| Side Return Extension | £21k – £43k |
| Wrap-Around Extension | £51k – £111k |
| Loft Conversion (Dormer) | £34k – £55k |
| Kitchen Extension | £26k – £51k |
| Basement Conversion | £68k – £170k |
| Garage Conversion | £13k – £26k |
Prices are guide figures for 2026 based on projects in the Hertfordshire area. PD = Permitted Development (no formal planning application needed in most cases). Actual costs depend on specification, site conditions, and scope.

Professional single storey extension design and planning for ground floor expansions
Typical: 6-12 weeks
Two-storey home extension design maximizing space and value
Typical: 8-16 weeks
Garden-facing extensions creating seamless indoor-outdoor living
Typical: 6-10 weeks
Narrow extensions utilizing side garden space efficiently
Typical: 6-12 weeks
Specialized kitchen and dining space extensions for modern living
Typical: 8-14 weeks
Converting attic space into valuable living areas
Typical: 6-10 weeks
Underground extensions creating additional living space
Typical: 12-20 weeks
Expert guidance through planning applications and permitted development
Typical: 8-16 weeks
Comprehensive extensions combining rear and side elements for maximum space
Typical: 10-18 weeks
Comprehensive whole-house renovation and modernization services
Typical: 12-24 weeks
Expert structural engineering services including underpinning and load-bearing work
Typical: 8-16 weeks
Converting garages into functional living spaces for bedrooms, offices, and studios
Typical: 4-8 weeksFrom the first phone call to moving into your new space — here is what to expect at every stage.
We visit your Datchworth property, discuss your vision, assess feasibility, and give you honest guidance on costs and planning routes.
Our architects create detailed plans, 3D visuals, and construction drawings tailored to your Datchworth home and how you want to live in it.
We prepare and submit your planning application, liaise with the local authority covering Datchworth, and handle building regulations documentation.
Our vetted builders bring the design to life. We oversee the build, conduct regular site visits, and manage quality at every stage.
Final inspections, building control sign-off, snagging checks, and handover — your new Datchworth space is ready to enjoy.
We design all types of extensions for Datchworth homes: single storey rear extensions that open onto the garden, double storey extensions for growing families, side return extensions that reclaim wasted space, wrap-around extensions for maximum impact, loft conversions that add bedrooms and value, kitchen extensions with open-plan living, and basement conversions where ground conditions allow.
Every design is developed around your property's specific structure, orientation, and the character of the East Hertfordshire streetscape. We use 3D visualisation so you can see exactly how the finished extension will look and feel before any work begins on site.
Many extensions in Datchworth can proceed under permitted development rights without a formal planning application — but this depends on your property type, location, and the scale of the proposed works. We assess this during our free consultation and advise on the simplest route to approval.
Where a full application is needed, our planning team prepares all drawings, design and access statements, and supporting documentation for submission to Hertfordshire County Council. We manage the process from start to finish, including responding to officer queries and negotiating amendments if required.

Extension completed in the East Hertfordshire area
Building regulations sign-off is essential before you can use your new Datchworth extension. We produce detailed construction drawings and specifications that cover all regulatory requirements — from foundations and structural steelwork through to insulation values, fire resistance, and drainage design.
Our team also manages the building control process on your behalf, scheduling inspections at key stages and ensuring that any site variations are documented and approved.
Choosing the right team for your Datchworth extension makes all the difference. We bring a blend of architectural creativity, planning strategy, and construction knowledge that ensures your project succeeds on every front — design, budget, and programme.
We have worked with homeowners across East Hertfordshire at every scale, from compact kitchen extensions to full double storey builds. No matter the size of your project, you get the same high standard of service and attention to detail.

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Ready to discuss your Datchworth house extension project? Book a free, no-obligation consultation with our experienced team. We will visit your property, carry out a thorough assessment of the available options, and provide clear, detailed guidance on costs, timelines, planning requirements, and the best route to approval. Whether you are considering a single storey rear extension, a loft conversion, or a full refurbishment, our Datchworth specialists are here to help. Call us today on 020 3051 9430 or request a callback online to get started.
Discover our comprehensive range of house extension solutions in London and surrounding areas
Professional single storey extension design and planning for ground floor expansions
Two-storey home extension design maximizing space and value
Garden-facing extensions creating seamless indoor-outdoor living
Narrow extensions utilizing side garden space efficiently
Specialized kitchen and dining space extensions for modern living
Converting attic space into valuable living areas
Call now to speak with our expert team. Get instant responses and professional guidance for your extension project.