Granny Annexes UK
Beautiful, energy-efficient granny annexes designed for independent living, extra family space and long-term property value.
A Complete Home in Your Garden — Designed Around Your Family
A granny annexe can give a parent or family member something difficult to achieve in any other way: independence, privacy and their own front door while remaining only a few steps away from family.
At MyGrannyAnnexe, we design and build fully finished garden annexes for year-round residential use. Each annexe can include a private bedroom, bathroom, fitted kitchen, living area, heating, electrical installation and practical storage, all designed around the available garden space and the needs of the person who will live there.
From the first site visit through design, planning, construction and final handover, our team manages the complete project
CONSTRUCTION EXPERIENCE 20+ YEARS
SIP PANEL SPECIALISTS
COMPLETE DESIGN & BUILD
10-YEAR STRUCTURAL GUARANTEE
MyGrannyAnnexe is part of TRJ Construction Ltd, combining specialist granny annexe design with decades of practical UK construction experience.
Explore Our Granny Annexe Designs
- Compact 1 Bedroom Annexe · 30 m² · 1 Bedroom · 1 Bathroom · From £70,000
- Accessible 2 Bedroom Annexe · 60 m² · Designed for easier mobility · From £135,000
- Spacious 1 Bedroom Annexe · 40 m² · 1 Bedroom · 1 Bathroom · From £90,000
- 2 Bedroom Granny Annexe · 60 m² · 2 Bedrooms · 2 Bathrooms · From £140,000
SIP Panels
From First Conversation to Moving In
Your Granny Annexe in 5 Clear Steps
01
Free Initial Consultation
Tell us who the annexe is for, the approximate garden size, your preferred layout and your budget. We can discuss suitable models, accessibility requirements and what may be possible on your property.
02
Site Visit, Design & Quotation
We assess the garden, access, ground conditions and routes for drainage, water and electricity. We then develop a layout suited to your site and provide a detailed quotation for the proposed works.
03
Planning & Approvals
We assess the appropriate planning route for the proposed annexe and can manage the required drawings, supporting information and application process on your behalf.
04
Construction & Fit-Out
Our team carries out the construction, services and internal fit-out, coordinating the project from foundations and SIP installation through to the kitchen, bathroom, electrical work and final finishes.
05
Final Inspection & Handover
Once the work is complete, we carry out the final checks with you, explain the installed systems and hand over your finished granny annexe ready for your family to enjoy.
What's Included in a MyGrannyAnnexe?
Design & Layout
Bespoke floor plan designed around the garden and the needs of the occupant.
Planning Support
Assessment of the appropriate planning route and preparation or coordination of the required application.
Foundations & Structure
Foundation solution selected for the site, followed by high-performance SIP floor, wall and roof construction.
Windows & Doors
Energy-efficient glazing configured around the layout, privacy and natural light requirements.
Kitchen
Fully fitted kitchen with cabinetry, worktops and provision for appliances.
Bathroom or Wet Room
Complete bathroom, shower room or accessible wet-room options.
Electrical Installation
Consumer unit, sockets, lighting and dedicated circuits as required.
Heating & Cooling
Energy-efficient heating and optional air-conditioning solutions for year-round comfort.
Flooring & Decoration
Internal finishes selected with the customer before construction.
Drainage & Services
Connection of water, drainage and electrical services subject to the existing property and site conditions.
Do I need planning permission for a granny annexe?
A self-contained granny annexe cannot automatically be treated as an ordinary garden outbuilding under permitted-development rules. The correct planning route depends on the proposed use, design, location and relationship with the main house. We assess this at the start of the project and can help manage the appropriate planning or approval process.
How much does a granny annexe cost?
Our current range starts from approximately £70,000, with prices increasing according to size, layout and specification. Ground conditions, drainage distances, electrical connections, glazing, kitchen and bathroom choices and accessibility requirements can all affect the final price. We provide a detailed quotation after discussing the project and assessing the site.
What is included in a granny annexe?
Our annexes can be provided as complete living accommodation including the insulated structure, windows and doors, internal walls, kitchen, bathroom, electrical installation, heating, flooring and decoration. Foundations and service connections are assessed for each property and clearly detailed in the quotation.
How long does a granny annexe take to build?
SIP construction allows the structural shell to be assembled much faster than many traditional construction methods. The overall project programme depends on the size of the annexe, specification, planning process, site access and service connections. We provide an expected construction programme before work starts.
Can a granny annexe be lived in all year round?
Yes. Our granny annexes are designed as comfortable year-round living spaces rather than seasonal garden buildings. High levels of insulation, energy-efficient glazing and appropriate heating or air conditioning can provide a comfortable internal environment throughout the year.
Can you build a wheelchair-accessible granny annexe?
Yes. We can design accessible granny annexes with step-free access, wider doorways, practical circulation space, accessible bathrooms or wet rooms and layouts tailored to the occupant’s mobility requirements. Our Oak Accessible design provides one starting point for this type of project.
Can you connect water, drainage and electricity to the annexe?
Yes. As part of the site assessment we look at suitable routes for electricity, mains water and drainage between the existing property and the proposed annexe. The distance, ground conditions and existing drainage levels are important factors in establishing the most appropriate solution and cost.
What areas do MyGrannyAnnexe cover?
We build granny annexes across Hertfordshire, Essex, North London and surrounding areas. If you are unsure whether your property is within our normal working area, contact us with your postcode and we can quickly confirm whether we can visit your site.
Could a Granny Annexe Work in Your Garden?
You don’t need to have a finished design before contacting us. Tell us approximately where you live, who the annexe is for and how much space you have available. We can discuss suitable layouts, likely planning considerations and the next steps towards creating a comfortable independent home in your garden.
Helping you build the best granny annex
No obligation. Speak directly with an experienced member of our construction team.
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