Building & Construction Services in London

We combine attentive service with proven capability to deliver high-quality construction projects — on time, on budget, and with minimal disruption.

New Build

Residential and commercial developments delivered on time and within budget, from design coordination to handover.

Learn more

Refurbishments

Full property upgrades: structural changes, kitchens, bathrooms, flooring, decoration and compliance.

Learn more

Property Maintenance

Reactive and planned works for homes and businesses: electrical, plumbing, carpentry, painting and more.

Learn more

Retrofitting

Energy-smart upgrades: insulation, windows, heating & controls, helping reduce bills and carbon footprint.

Learn more

Popular Project Types

House Extensions

Rear, side return and wrap-around extensions with full structural works, MEP and finishes.

Learn more

Loft Conversions

Maximise unused space with dormers, hip-to-gable, L-shape, skylight (Velux) and more.

Explore lofts

Basement Conversions

Specialist excavation, structural works and waterproofing (Type A/B/C) with full fit-out.

Learn more

Loft Conversion Types

Choose the configuration that fits your home and goals.

Dormer Loft

Add a full-height room with excellent headroom and natural light.

View

Hip-to-Gable

Extend the roofline to unlock full-width usable space.

View

Mansion Block

Heritage-sensitive lofts for mansion blocks & period buildings.

View

L-Shape Dormer

Ideal for terraces—two rooms plus bathroom layout.

View

Pod Dormer

Create an extra bedroom or en-suite at the rear pod.

View

Skylight / Velux

Fast, cost-effective conversion with roof windows only.

View

Roof Terrace

Design, structure, drainage and finishes for roof decks.

View

House Extension Types

Choose the extension style that best suits your property and lifestyle.

Rear House Extension

Extend into the garden to create spacious kitchens, living rooms, or open-plan layouts.

View

Side Return Extension

Use the alleyway space to widen kitchens and dining areas in terraced or semi-detached homes.

View

Wrap Around Extension

Combine rear and side return for maximum space—ideal for large open-plan family areas.

View

Double Storey Extension

Add bedrooms, bathrooms or office space with a two-floor extension that boosts value.

View

The Bigness Process

How we plan, deliver, and care for your property — responsibly, over its lifetime.

Planning & Property Assessment

  • Clear scope & objectives aligned to long-term outcomes.
  • Responsible House check to identify risks (moisture, heat loss, future upgrades).
  • Accurate surveys & takeoffs to prevent surprises and variations.
  • Risk & contingency planning for time, budget, and buildability.

Execution & Quality Control

  • Right team with the skills needed for the scope and detailing.
  • Transparent communication with clear updates and decisions recorded.
  • Quality checkpoints to prevent defects, rework, and hidden problems.
  • Controlled delivery to keep progress predictable and compliant.

Handover & Ongoing Care

  • Clean handover with what was improved and what to monitor.
  • Future-ready guidance so upgrades later are easier and safer.
  • Planned maintenance options to protect the property over time.
  • Responsive support when issues arise or changes are needed.

Frequently Asked Questions

Answers to the most common questions about our construction and property services in London.

Q Do I need an architect, or can Bigness handle design?
We’re happy to collaborate with your architect or deliver a full **design & build** service. For lofts, extensions and refurbishments we can manage drawings, structural design and building control submissions.
Q Do you manage planning permission and building control?
Yes. We advise whether your project falls under **Permitted Development** or requires planning consent, prepare the application, handle **party wall** matters where needed, and coordinate **Building Control** sign-off.
Q What areas do you cover?
We cover **all London boroughs** and the surrounding areas (Greater London, parts of Surrey, Essex and Kent).
Q How long do projects typically take?
Timelines vary by scope. Typical ranges:
• Loft conversion: **6–10 weeks** · House extension: **10–16+ weeks** · Refurbishment: **4–12+ weeks**
We create a detailed programme with milestones before starting on site.
Q Can we live in the property during works?
Often, yes—especially for lofts and some refurbishments. We set up dust protection, safe access and phased works. For major structural or basement projects, temporary accommodation may be more practical.
Q Are you insured and qualified?
Yes. Bigness carries full public & employer’s liability insurance. Trade specialists are appropriately qualified (e.g. Gas Safe for heating, certified electricians for compliance), and projects follow strict **Health & Safety** procedures.
Q Do you offer fixed-price quotes? What’s included?
We provide clear, itemised **fixed-price quotations** based on drawings and a detailed scope. Inclusions and exclusions are stated up front, along with a realistic programme and payment schedule.
Q What warranties do you provide?
Workmanship warranty is provided on completion, plus manufacturer warranties on installed products and systems. You’ll also receive certificates and manuals where applicable.
Q Can you help with energy-efficient upgrades and retrofitting?
Absolutely. We deliver **insulation upgrades, efficient heating/controls, windows & doors** and other retrofit measures to improve comfort and reduce running costs.
Q How do we get started?
Tell us about your project and we’ll arrange a site visit or video call. You’ll receive a clear proposal with scope, costs and timeline. Request a Free Quote →

Not sure where to start?

Tell us about your project and we’ll advise the best route.