PECASA designs, manufactures and installs bespoke garden rooms across Hertfordshire from its Watford base, serving homeowners in areas including Watford, Radlett, Bricket Wood, St Albans, Bushey, Borehamwood and surrounding towns. Each room is designed around the garden, access, intended use and long-term requirements, then precision prepared locally and professionally installed on site. The aim is a comfortable, fully insulated space that works as an office, gym, studio, family room or flexible extension of everyday life.
120+Successfully Completed Projects
20 Years’ construction experience
Bespoke Garden Rooms Hertfordshire - Locally Manufactured, Fully Insulated & Made for Year-Round Use
Real Garden Room Price Examples - VAT Included
A useful garden-room price should show what size and specification it relates to. PECASA publishes model examples with VAT included, giving homeowners a realistic starting point before the design is adapted to the site.
Published PECASA model examples (including VAT)
Bespoke garden rooms
Pricing Guide for every size
Premium builds, precision made. Installed in as little as 8–18 days.
Bespoke design
Tailored to you
Made in Britain
Built in our factory
Ground screw foundation
Stronger. Cleaner. Greener.
8–18 days
Installation in as little as 8–18 days*
Independent warranty
For total peace of mind
| Size (m) Depth × Width |
3m wideApprox. 8m² (e.g. 2.8 × 3.0) | 4m wideApprox. 10–12m² (e.g. 2.8 × 4.0) | 5m wideApprox. 14m² (e.g. 2.8 × 5.0) | 6m wideApprox. 17m² (e.g. 2.8 × 6.0) | 7m wideApprox. 20m² (e.g. 2.8 × 7.0) | 8m wideApprox. 22m² (e.g. 2.8 × 8.0) |
|---|---|---|---|---|---|---|
| 2.8m deepCompact & efficient | £22,300 | £26,300 | £30,300 | £34,300 | £38,300 | £42,300 |
| 3m deep★ Most popular | £24,300 | £28,300 | £32,300 | £36,300 | £40,300 | £44,300 |
| 3.5m deepExtra comfort | £26,300 | £30,300 | £34,300 | £38,300 | £42,300 | £46,300 |
| 4m deepMore space | £28,300 | £32,300 | £36,300 | £40,300 | £44,300 | £48,300 |
| 5m deepMulti-purpose space | £32,300 | £36,300 | £40,300 | £44,300 | £48,300 | £52,300 |
2.8m deepCompact & efficient▾
3m wideApprox. 8m²£22,300
4m wideApprox. 10–12m²£26,300
5m wideApprox. 14m²£30,300
6m wideApprox. 17m²£34,300
7m wideApprox. 20m²£38,300
8m wideApprox. 22m²£42,300
3m deep★ Most popular▾
3m wideApprox. 8m²£24,300
4m wideApprox. 10–12m²£28,300
5m wideApprox. 14m²£32,300
6m wideApprox. 17m²£36,300
7m wideApprox. 20m²£40,300
8m wideApprox. 22m²£44,300
3.5m deepExtra comfort▾
3m wideApprox. 8m²£26,300
4m wideApprox. 10–12m²£30,300
5m wideApprox. 14m²£34,300
6m wideApprox. 17m²£38,300
7m wideApprox. 20m²£42,300
8m wideApprox. 22m²£46,300
4m deepMore space▾
3m wideApprox. 8m²£28,300
4m wideApprox. 10–12m²£32,300
5m wideApprox. 14m²£36,300
6m wideApprox. 17m²£40,300
7m wideApprox. 20m²£44,300
8m wideApprox. 22m²£48,300
5m deepMulti-purpose space▾
3m wideApprox. 8m²£32,300
4m wideApprox. 10–12m²£36,300
5m wideApprox. 14m²£40,300
6m wideApprox. 17m²£44,300
7m wideApprox. 20m²£48,300
8m wideApprox. 22m²£52,300
Prices include VAT. Final price may vary based on exact specification, site conditions and any additional options. *Timescales vary by project.
What's included as standard
- SIP construction (walls, roof & floor)
- Ground screw foundation system
- EPDM rubber roof
- High performance windows & doors
- External cladding (choice of finishes)
- Electrical & data (internal fittings)
- Tape-and-joint internal finish
- Decoration (painting & lighting)
Popular upgrades
Air conditioning & heating
Kitchenette & bathroom
Decking & patio areas
Smart home features
Bespoke storage & furniture
Independent warranty
All our buildings are backed by an independent 10 year insurance-backed warranty for complete peace of mind.
Made in BritainDesigned & built by Pecasa
Quick installation8–18 days (typical)
Bespoke design serviceFree 3D visualisations
Book your free surveywww.pecasa.co.uk · 020 8146 2200
Prices include VAT. Final price may vary based on exact specification, site conditions and any additional options.
*Timescales vary by project.
Pricing note: These are current published model examples, not fixed quotes for every site. Bespoke dimensions, access, ground conditions, glazing, services, bathrooms/kitchenettes, air conditioning, decking and other options can change the final price. The written PECASA quotation should govern the final scope and cost.
What Is Included as Standard?
PECASA’s current published premium build standard includes the principal structure, weatherproofing, internal finish and core services rather than presenting an empty shell price. The exact quotation for your project remains the controlling document, but the current website identifies the following as standard or core specification items:
| Element | Current PECASA published standard |
|---|---|
| Foundations | Ground-screw foundation system on suitable sites |
| Roof | High-performance EPDM rubber roofing |
| Openings | High-performance windows and doors / modern glazing |
| Exterior | External cladding with finish choices, subject to the selected specification |
| Interior | Plasterboard / tape-and-joint internal finish and decoration |
| Electrical | Integrated internal lighting and electrics; data provision can be specified |
| Floor | Quality flooring included in PECASA’s published premium build standard |
| Comfort options | Air-conditioning / heating and other upgrades can be specified where required |
Popular upgrades can include air conditioning and heating, a kitchenette or bathroom, decking and patio works, smart-home features, bespoke storage and other project-specific finishes. These should be separated clearly in the quotation so you can see what is standard and what is optional.
Current SIP Construction Specification
PECASA’s current structural approach uses Structural Insulated Panels (SIPs) as standard. SIPs combine structural oriented strand board (OSB) faces with a rigid insulation core, creating an insulated structural envelope when designed and installed correctly. PECASA states that its panels are manufactured and pre-assembled off site at its local Watford facility, reducing cutting, waste and disruption in the customer’s garden.
- SIP structural shell: walls, roof and floor are formed using the SIP system in PECASA’s published garden-room specification.
- Foundation interface: the SIP structure is commonly supported on a project-specific ground-screw grid, subject to the site survey, ground conditions and structural requirements.
- Weather protection: the roof is finished with a high-performance EPDM membrane, with exterior cladding and high-performance glazing completing the envelope.
- Internal finish: PECASA’s current published build standard includes a tape-and-joint / plasterboard finish, lighting, electrics and flooring.
- Panel thickness is project-specific: PECASA does not publish one universal SIP thickness for every building. As a recent reference point, its July 2026 Bricket Wood project used 120 mm PIR insulation.
Why this matters: thermal comfort is determined by the complete envelope – walls, floor, roof, glazing, air-tightness, ventilation and heating/cooling choices – rather than by a single insulation number.
Many detached garden rooms used for purposes incidental to the main house can fall within Class E householder permitted-development rights in England, but that is not automatic. The design must satisfy the relevant limits and conditions, and permitted-development rights can be restricted or removed for a particular property.
- Class E is for buildings used for purposes incidental to the enjoyment of the house. It does not cover separate self-contained accommodation or primary residential use such as a bedroom, bathroom or kitchen as the main living accommodation.
- As a headline rule, buildings and other relevant additions cannot cover more than 50% of the curtilage around the original house, and height/location limits apply. A building within 2 metres of a boundary is generally limited to 2.5 metres overall height if relying on Class E permitted development.
- Listed buildings, conservation/designated areas, Article 4 directions, planning conditions and previously removed permitted-development rights can change the position. A Lawful Development Certificate may be useful where certainty is important.
Across Hertfordshire, the relevant local planning authority varies by district – for example Hertsmere, St Albans, Watford, Dacorum and others. The national Class E rules are the starting point, but local designations and property-specific planning history still need to be checked.
Building Regulations are separate from planning permission. Planning Portal guidance states that a detached outbuilding under 15 m² with no sleeping accommodation will not normally need Building Regulations approval. Between 15 m² and 30 m², approval will not normally be required if there is no sleeping accommodation and the building is either at least 1 metre from a boundary or is constructed substantially of non-combustible materials. Larger buildings, sleeping accommodation, drainage, certain electrical/plumbing works and other circumstances can trigger additional requirements. The final position should be checked for the individual project.
What Customers Say
Frequently asked questions regarding garden room design in Herts
1. What does your garden room design service in Herts include?
Our Garden Rooms Design Herts service includes all the work from the first drawings and room layouts and the selection of the best materials for the job to the signing off of the final design. We prioritise function and design to align with your home and way of living.
2. Can I have different designs for my garden room?
Yes. With Garden Rooms Design Herts, every work is different. You can have different designs for the size, configuration, glass type, and additions to the garden room to have it work the way you want.
3. Are your garden room designs for use all year round?
Yes. All of the designs made from our Garden Rooms Design Herts service have insulation, ventilation, and comfort.
4. Do you assist with the planning and design compliance?
Yes. With our Garden Rooms Design Herts service, we give advice for the garden room design that is within your local area.
5. How do I start the design process?
Preliminary design discussions with our team and/or the online design planning tool for preference outlines (prior to more involved design work) are good ways to start.
Design Your Garden Room With PECASA
Because PECASA manufactures locally from Watford, Hertfordshire homeowners can move from survey to a site-specific design with a team that understands local plots and access conditions. Start with the free consultation and survey, then visualise the proposed room in PECASA’s online 3D designer.