Kitchen and house extensions in London. Rear, side return and wraparound extensions, designed, priced and built by one team.
A successful extension begins long before excavation or steelwork. The early decisions determine whether construction feels controlled or reactive. What must the space achieve? How does it connect to the existing house? What approvals are needed, and what does the complete budget include?
Use this checklist before committing to a design or start date. NU Projects provides integrated extension and loft-conversion services. They run from architecture and cost planning through construction and interiors.
1. Define the brief
- Which daily problems must the extension solve?
- Which rooms and storage functions are required?
- How should the new space connect to the garden?
- Which existing rooms will be remodelled as a consequence?
- What investment range and completion date are realistic?
The brief should describe how the home needs to work. It is not only the number of square metres to add.
2. Check planning and property constraints
Some house extensions may qualify as permitted development. That applies when national limits and conditions are met. Flats, listed buildings and conservation areas can alter the position. So can Article 4 directions, previous extensions and local policy. Review the Planning Portal extension guidance. Then obtain advice for the address before relying on permitted development.
3. Survey the existing building
A measured survey should be supported by investigation. That covers structure, drains, levels, trees, services, party walls and existing defects. Unknown conditions become expensive when discovered after the construction sequence has already been committed.
4. Design light, layout and garden together
More glazing does not automatically create a better room. Orientation, overheating, privacy and views all matter. So do ceiling form and the depth of the existing house. Rooflights, courtyards and changes in level can work better than a wall of glass.
5. Coordinate structure and MEP
Steelwork, drainage, underfloor heating, ventilation, lighting, kitchen extract and controls must be designed together. The technical package should explain how the space will be built and serviced. It should not merely show how it will look.
6. Address party walls and neighbours
Work near shared walls, boundaries or adjoining foundations may engage the Party Wall etc. Act. Government guidance explains the basic process. Review party-wall and building-work guidance and appoint appropriate professional advice where required.
7. Build the complete cost plan
Include design and consultants, statutory costs, structural work and building services. Add kitchen, joinery, finishes, landscaping, preliminaries, contingency and VAT. A headline build rate without these elements is not a complete project budget.
8. Plan procurement and construction
Windows, rooflights, kitchens, stone, specialist glazing and bespoke joinery may drive the programme. Agree samples, lead times and decision dates before mobilisation. Define site access, protection, welfare, deliveries and neighbour communication.
9. Confirm handover and aftercare
The finish line should include commissioning, certification and operating information. It should also include snagging and a defined defects process. This is particularly important where the extension introduces new heating, ventilation or controls.
View completed projects for examples of integrated residential delivery.
See the Chelsea basement and extension project. It is a completed example of NU Projects’ residential delivery.
Frequently asked questions
How early should a contractor be involved?
Early enough to advise on buildability, logistics, procurement and cost. That advice should come while the design remains flexible.
Can I stay in the house?
Sometimes, but the answer depends on services disruption, structural work, access and safety. The logistics and cost implications should be planned honestly.
Does permitted development remove the need for building regulations?
No. Planning and building regulations are separate systems. Structural, thermal, fire, drainage and other requirements still need to be addressed.
Plan your extension with one accountable team
Book a private consultation with NU Projects. We will test the brief, feasibility, cost and delivery route.
This is the work we do. Kitchen and house extensions in London, or ask for a cost estimate.
Published 21 April 2021. Written by the NU Projects studio, edited since for house style and accuracy.