Are you fantasizing about a bigger kitchen, open plan living or addition of an extra bedroom without moving out of your favourite neighbourhood? House Extension in London might be the answer to your dream.

As house prices go up and there is no more space in the capital, one of the best investments that you can ever make is the expansion of your house. We are BBS construction UK where we design and construct beautiful house extensions that do not only add value, but also change your lifestyle.

 

Why a House Extension in London Is the Best Home Investment

The dilemma that is facing London homeowners is often between moving and improving. Stamp duty, transport costs and the pain of moving into a new house are among some of the factors that are forcing more families to extend rather than change.

This is why a house extension is so rational:

Benefit	Description
Increases Property Value	A well-designed extension can add 10–25% to your home’s value.
Avoids Moving Hassles	Stay in your current area, keep your neighbours, schools, and routines.
Customized Living Space	Tailor every detail — from layout to lighting — to match your lifestyle.
Sustainable Solution	Reusing your existing footprint and improving insulation reduces energy use.
Adds Luxury and Comfort	Create bright, open spaces for modern living with bi-fold doors or skylights.

 

Types of House Extensions in London

London architecture is varied: there are Victorian terraces and modern detached houses, this is why all houses have their own opportunities.

The following are the most frequently requested house extensions that are provided by us:

Type of Extension	Description	Ideal For	Planning Requirement
Rear Extension	Extends into the garden, ideal for larger kitchens or family rooms.	Homes with ample backyard space.	Usually permitted under Permitted Development.
Side Return Extension	Converts the unused narrow alley along the side of terraced houses.	Period homes with side access.	Often falls under Permitted Development.
Wrap-Around Extension	Combines rear + side return for maximum space.	Homeowners wanting open-plan layouts.	Planning permission is often required.
Double-Storey Extension	Adds space both downstairs and upstairs.	Families needing bedrooms & living areas.	Requires planning permission.
Loft or Roof Extension	Converts attic into habitable rooms.	Homes with sufficient roof height.	Permitted within volume limits.
Basement Extension	Excavates below your home for new living or office space.	Central London homes with limited gardens.	Full planning and structural assessment needed.

 

Step-by-Step Process: How We Delivers Perfection

We feel that all extensions can be relaxed and enjoyable at the BBS Construction UK. We have a process that guarantees us a smooth planning, clear communication and good workmanship.

 

1. Free Consultation & Site Survey

We come to your house, see your ambitions, and calculate available space. Our specialists evaluate the feasibility and talk about the design ideas that suit you.

 

2. Concept & Design

Our design team will draw up 2D and 3D plans that will visualise your extension. We focus on:

• Maximising light and space
• Existing architecture matching.
• Optimising structural integrity and insulation.

 

3. Planning Permission & Building Regulations

We even do the paper work, applications and liaise with the local councils to have approvals within a short duration of time.

Quick Guide: What Needs Permission?

Project Type	Planning Permission Needed?	Building Regulations Needed?
Rear extension under 6m (semi-detached)	❌ No	✅ Yes
Double-storey extension	✅ Yes	✅ Yes
Loft conversion with dormer	❌ Usually no	✅ Yes
Basement excavation	✅ Yes	✅ Yes

 

Tip: Although planning permission may not be necessary, it must always have building regulations approval that will assure the quality and safety.

 

4. Structural Calculations & Engineer Collaboration

The engineers of our facility are involved with:

• Foundation assessment
• Beam and load calculations
• Wall removals and steel installations.
• Drainage adjustments

 

5. Construction Phase

We handle all stages, beginning with preparations to the final touches:

• Groundwork: Foundation pouring and excavation.
• Structure: Bricks, roof, insulation.
• Internal Works: Plumbing, electrics, plastering.
• Finishes: Flooring, fixtures, painting.

We make the working place safe, clean, and tidy at any time.

 

6. Final Inspection & Handover

We have a thorough inspection before it is completed to make sure that all is in:

• Building regulations
• Design specification
• Customer satisfaction

You are given completion certificates and peace of mind warranty.

 

House Extension London: Cost Breakdown (2025 Estimates)

Prices vary depending on the nature of property, materials, access and complexity of design. The following table presents a rough budget outlay guide.

Extension Type	Average Cost per m²	Typical Total (20m²)	Notes
Rear Extension	£1,800 – £2,800	£36,000 – £56,000	Common for kitchen/dining area.
Side Return Extension	£2,000 – £3,000	£40,000 – £60,000	Ideal for narrow plots.
Wrap-Around	£2,500 – £3,500	£50,000 – £70,000	Combines rear + side.
Double-Storey	£2,800 – £4,000	£60,000 – £80,000	Adds extra bedroom & bathroom.
Loft Extension	£1,500 – £2,500	£30,000 – £50,000	Depends on dormer size.
Basement Extension	£3,500 – £5,000	£70,000 – £100,000+	Complex structural work.

 

Tip: In your budget be sure to always have a contingency of 10-15% in the budget in case of unexpected costs such as drainage or structural adjustments.

 

Timeline for a House Extension Project

The following is an example of a schedule:

Stage	Duration	Tasks Included
Design & Planning	4–8 weeks	Survey, drawings, council submissions
Structural Calculations	2–3 weeks	Engineer reports, approvals
Construction	10–20 weeks	Foundation to finishing works
Final Inspection	1 week	Certification, clean-up, handover

 

Average total time: 4–6 months, depending on complexity and weather.

 

Key Things Every Homeowner Must Know Before Extending

The following are the lessons that every homeowner should learn and before making the plunge:

1. Party Wall Agreement – In the process of carrying out your work close to a shared wall or a boundary you are required to inform the neighbours in a legal manner.

2. Access Arrangements –Buildings may need side access or rear access; consider logistics on plan early.

3. Utilities & Drainage – In the present instance, the cost and design can be influenced by a change in the location of pipes or meters.

4. Insurance – Get your insurance cover renovated.

5. Energy Efficiency – Insulate, use, and install LED lights and double glazing to conserve in the long-term.

6. Sustainability – Recycle, recycled steel and wood, which is FSC-certified.

7. Future-Proofing – Plan your layout such that it can be easily re-purposed or re-sold in future.

 

How a House Extension Can Transform Your Lifestyle

An extension that is well designed does not only put extra square feet on your house, but it totally reformats your everyday life.

Lifestyle Goal	Extension Type	Result
Open-plan family living	Rear / Wrap-around	Seamless kitchen-diner space
Home office or studio	Loft / Side return	Quiet, dedicated workspace
Rental income	Double-storey / Annex	Create a self-contained flat
Luxury entertainment area	Rear extension	Bi-fold doors, skylights, bar area
Sustainable upgrade	Any type	Better insulation, lower bills

 

Why Choose BBS Construction UK for Your House Extension

Here’s why homeowners across Harrow, Wembley, Edgware, and North London trust us:

Feature	What We Offer
Experienced Team	15+ years of industry experience in London homes.
Design-to-Build Service	Full support from design, planning to completion.
Transparent Pricing	No hidden charges, clear contracts, honest advice.
Quality Materials	Durable, eco-friendly, and sourced from trusted suppliers.
Customer Satisfaction	5-star reviews for reliability and professionalism.
On-Time Delivery	We work with strict project schedules and milestones.

 

We made our small kitchen look magnificent with a living space. The keenness of the eye was marvelous! – Client Review, Harrow

 

Ready to Extend Your Home? Let’s Build Together

Turn your home into the home of your dreams with our expert team for Home Extension London solutions.

We deal with design, planning, permissions and construction, and then you can be assured that you will have peace of mind throughout.

 

Frequently Asked Questions (FAQs)

1. Should I always have planning permission of house extension in London?
   Not always. A vast number of extensions are under Permitted Development Rights. On the other hand, formal approval is necessary in listed buildings and conservation areas.
2. And what will be the total duration of the process?
   Most of the projects require 46 months between design and completion.
3. Am I allowed to reside in my house when it is being built?
   Yes, in most extensions that are single-storey. We maintain a minimum amount of disruption and maintain work zones.
4. Is an extension going to raise my council tax?
   No, as a rule, unless the property is reassessed following significant changes.
5. What will I do to guarantee my builder?
   Select certified experts such as BBS Construction UK, who offers contracts and offer insurance and reference.