Modular House Extensions
Where a traditional extension means months of building work against the house, a modular extension is manufactured off site and installed in a fraction of the time — either linked to the house or as a detached building in the garden.
Extra space without living on a building site
The decision is usually whether to link the new space to the house or keep it detached. Detached is simpler — no structural opening, no party-wall complications — and is often what people actually need when they want a bedroom, office or living room.
- Detached garden building, or a linked structure alongside the house
- Bedroom, office, living room or gym layouts
- Shower room or WC where drainage allows
- Cladding matched or contrasted with the existing house
- Short site programme — base, craneage and connections
- Relocatable if you move or reconfigure the garden
Example configurations
Combine P300, P400 and P600 units to tailor room sizes and footprints. Matching units can also stack over two storeys.
A single extra room — office, bedroom or snug.
Living space with a shower room, or two separate rooms.
A full annexe-scale extension with bedroom, bathroom and living area.
Modular House Extensions — key facts
- P300 unit
- 2.9m × 2.2m externally; approximately 2.7m × 2.0m usable internally
- P400 unit
- 3.9m × 2.2m externally; approximately 3.7m × 2.0m usable internally
- P600 unit
- 5.9m × 2.2m externally; approximately 5.7m × 2.0m usable internally
- Configuration
- Mix P300, P400 and P600 units to create tailored footprints and shapes
- Unit height
- 2.40m external / 2.16m internal
- Storeys
- Up to two storeys, subject to final project design
- Delivery
- UK mainland and Northern Ireland — transport quoted separately
Adacon modular buildings use P300, P400 and P600 units with external lengths of 2.9m, 3.9m and 5.9m, a common 2.2m width and 2.40m external / 2.16m internal height. The sizes can be combined to create more tailored floor areas and building shapes, joined side by side or stacked to two storeys subject to the final project design.
What's available
Modular House Extensions — photo gallery
Whether a building can be used as a permanent dwelling, and what Building Regulations, planning permission, foundations and energy-performance requirements apply, depends entirely on your site and how the building will be used. We make no blanket claim that a standard configuration constitutes a compliant dwelling — this must be confirmed for your specific project.
Modular House Extensions — common questions
Design your extension
Choose the size, rooms and cladding and get an estimated price.
Related homes
Self-contained garden annexes and granny flats for parents, relatives, guests or family living — bedroom, kitchen, bathroom and living space, designed online.
Modular guest accommodation for the garden — a self-contained guest room with shower room and kitchenette, insulated and delivered fitted out.
Two-storey modular homes built by stacking matching P300, P400 and P600 units — living space below, bedrooms above, with internal or external stairs.
Design options for this build
All design optionsOther things we build
What do you need to build?Useful guides
Yes — P600 modules can be stacked to create two-storey modular offices, welfare blocks and clubhouses, with an internal or external staircase.
Practical guidance on module sizes, configuration, fit-out and the factors that shape a tailored modular-building quotation.
Whether a modular building needs planning permission depends on its use, size, siting and duration. Read how the common cases usually work in the UK.
Get a price for Modular House Extensions
Tell us what you need and we'll come back with pricing and lead times — usually within one working day.