01
Basement conversions
Add a full floor of living space under your home, from cinema rooms and gyms to guest suites and family kitchens. Fully waterproofed and built to last.
Explore servicePremium Basements, Extensions, Home Builds & Refurbishments In South West London
No missed deadlines, no surprise costs, no cutting corners. We build it right first time, with a dedicated project manager, clear fixed pricing and a 10-year workmanship warranty on every project.
A smaller builder for homeowners who care about the detail
Building Spaces Construction is a South West London building contractor with a team that has been building and renovating homes in the area since 2009. We take on a small number of high-end projects at a time: basement conversions, high-end refurbishments, kitchen extensions, bespoke loft conversions and new homes.
That is a deliberate choice. Every project is run by one dedicated project lead from the first site visit to handover, so you always know who is responsible and who to call. 92% of our work comes through recommendations, and we would like to keep it that way.
See our building services
What we build
02
High-end refurbishments
Whole-house renovations of period and modern homes to a premium specification, from structural work to bespoke joinery and luxury finishes.
Explore service
03
Kitchen extensions
Rear, side return and wraparound extensions that open your ground floor to the garden, with steel, glazing and rooflights done properly.
Explore service
04
Bespoke loft conversions
Mansard, dormer and hip-to-gable lofts designed around your house, not a standard box.
Explore service
05
New builds
Contemporary and traditional new homes on infill plots, or knock-down-and-rebuild projects, managed from planning to handover.
Explore serviceWhy homeowners choose Building Spaces
- 01
One team, one point of contact.
The same project lead runs your job from start to finish, so decisions are made quickly and nothing gets lost between a salesperson and a site team.
- 02
Local experience since 2009.
We know the Victorian and Edwardian terraces of SW11, SW12 and SW4, their foundations, party walls and planning quirks.
- 03
Right first time.
Careful planning and close attention to detail mean fewer surprises, fewer snagging lists and a better finish.
- 04
Flexible as your plans change.
Projects evolve. We adapt the specification with you and keep the costs clear.
- 05
Protected work.
Every project carries a 10-year workmanship warranty, and we are CHAS accredited for health and safety.
Building Spaces in numbers
2009Building in South West London since
2,000+projects completed
10-yearworkmanship warranty
92%of work from recommendations and repeat clients
How a project works
- 01Free consultation. Our team visits, listens to your ideas and looks at the property.
- 02Design and planning. We work with your architect, or introduce one, and handle planning and party wall steps.
- 03Detailed quotation. A clear, itemised quotation with no vague provisional sums where we can avoid them.
- 04Build. A fixed programme, regular updates and a tidy, safe site.
- 05Handover. A final walk-round, snagging, and your 10-year workmanship warranty.
Recent projects
Sample project, not a verified case study
Sample project 1: Basement conversion, Battersea SW11. A family room and guest suite under a Victorian terrace, lit by a walk-on rooflight.
Sample project, not a verified case study
Sample project 2: Side return kitchen extension, Balham SW12. A glazed side return and steel-framed doors opening a dark galley kitchen onto the garden.
Sample project, not a verified case study
Sample project 3: Mansard loft conversion, Clapham SW4. A principal bedroom suite with en suite and built-in eaves storage, in a conservation area.
Sample project descriptions are placeholders to replace with verified project details before launch.
Do you need planning permission?
Answer six quick questions about your house and project, and our free checker will show whether you are likely to need planning permission, a party wall notice or both. It covers Wandsworth, Lambeth and Merton.
What our clients say
Most of our work comes from recommendations. Here is what a few of our clients have said.
"From the first visit to handover, the team was organised, tidy and honest about costs. Our basement is beautifully finished and completely dry, and our neighbours were kept informed throughout."
Sarah, Battersea SW11 · Basement conversion
"We stripped our Victorian terrace back to the brick and the team handled everything: steelwork, rewiring, joinery, the lot. They restored the original cornicing and the house has never looked better."
James, Clapham SW4 · Full refurbishment
"Our side return extension finished on schedule and the steel-framed doors are stunning. Every change we asked for was priced up front, so there were no surprises at the end."
Priya, Balham SW12 · Kitchen extension
Sample reviews shown for layout only. Replace with real client reviews before launch.
Where we work
We work across South West London, mainly in Battersea, Balham, Clapham, Tooting, Wandsworth, Earlsfield and Wimbledon. If you live nearby, get in touch and we will tell you honestly whether we are the right fit.
Common questions
Do you offer free quotations?
Yes. A member of our team will visit your home, talk through the project and then send a detailed written quotation. There is no charge and no obligation.
Which areas of London do you cover?
We mainly work in South West London: Battersea (SW11), Balham (SW12), Clapham (SW4), Tooting (SW17), Wandsworth and Earlsfield (SW18) and Wimbledon (SW19).
Do you guarantee your work?
Yes. Every project comes with a 10-year workmanship warranty.
Can you work with my architect?
Yes. We regularly build from architects' drawings. If you do not have an architect yet, we can recommend one we trust.
Do you take on standard loft conversions?
We focus on bespoke and high-end work, so we are not usually the cheapest option for a standard box dormer. If your loft needs careful design or sits within a wider renovation, we would be glad to help.
Ready to add space and value to your home?
Tell us about your project and we will call you back within one working day. Quotations are free and there is no obligation.