Extensions & Renovations
Create the Home You've Always Wanted
Professional house extensions and renovations transform your property to match your lifestyle — whether you need more space, a modern kitchen, an extra bedroom, or a complete home overhaul. From single-storey rear extensions and loft conversions to full-house renovations and period property restorations, we handle every aspect of your project with professional project management, quality workmanship, and transparent pricing. Across the Cotswolds and Gloucester, we deliver extensions and renovations that add space, value, and character to your home.
Why Choose a House Extension or Renovation?
Extending or renovating your home is often smarter than moving — you avoid stamp duty, estate agent fees, and the stress of relocating, while creating a home tailored to your needs. Professional extensions and renovations offer:
✅ More space without moving — add bedrooms, bathrooms, living areas, or kitchen space exactly where you need it
✅ Increased property value — well-executed extensions typically add 10–20% to property values in the Cotswolds
✅ Modern, functional layouts — open-plan living, en-suite bedrooms, utility rooms, home offices
✅ Improved energy efficiency — new insulation, double glazing, modern heating systems reduce running costs
✅ Period property restoration — carefully restore character features while adding modern comforts
✅ Cost-effective vs. moving — avoid stamp duty (up to £15,000+ on average homes), estate agent fees, and removal costs
✅ Tailored to your lifestyle — design the space exactly how you want it, not how the previous owner left it
Whether you're adding a single-storey kitchen extension in the Cotswolds, converting a loft near Chipping Norton or Cirencester, or undertaking a full renovation in Gloucester, professional project management ensures your extension or renovation is completed on time, on budget, and to the highest standards.
Our Extensions & Renovations Services
As a local Cotswolds builder and renovation specialist, we handle all aspects of extensions and home improvements with professional project management and quality workmanship :
1. Single-Storey Extensions
Single-storey extensions are the most popular way to add space — typically used for larger kitchens, open-plan living areas, utility rooms, or additional ground-floor bedrooms.
Types of single-storey extensions:
Rear extensions — extend from the back of your property (most common, often permitted development)
Side extensions — extend along the side of your property (ideal for narrow plots or terraced houses)
Side return extensions — fill in the side passage of Victorian/Edwardian terraced houses to create large open-plan kitchens
Wrap-around extensions — combine rear and side extensions for maximum space (L-shaped)
Conservatory-style extensions — heavily glazed with bi-fold or sliding doors for garden views
What's included:
Foundations (strip footings or trench fill, typically 1m deep)
Blockwork or timber frame walls with cavity insulation
Flat roof (warm roof construction with insulation above joists) or pitched roof (tiled to match existing)
Windows and doors (uPVC, aluminium, or timber — bi-fold, sliding, or French doors)
First-fix electrics and plumbing
Plastering and decorating
Flooring installation (tiles, engineered wood, LVT, etc.)
Kitchen installation (if part of the package)
Typical timeline: 8–12 weeks from start to finish for a standard 3m x 4m rear extension.bestbuilders.co
Typical cost: £1,650–£2,400 per m² for standard specification, or £2,750–£3,300+ per m² for high-spec with glazed walls, rooflights, and underfloor heating.
2. Double-Storey Extensions
Double-storey extensions maximise space by building upward — ideal for adding bedrooms, bathrooms, or living space on the first floor while expanding ground-floor accommodation.
When double-storey makes sense:
You need more space on both ground and first floors
Your plot is too small for a large single-storey extension
You want to add an en-suite bedroom above a kitchen extension
You're extending a bungalow to create a two-storey home
You want better value per m² (double-storey is typically 15–20% cheaper per m² than single-storey)
What's included:
Reinforced foundations (wider footings to support two storeys)
Structural steel beams or RSJs if removing load-bearing walls
Blockwork or timber frame walls with cavity insulation
First-floor joists and flooring
Pitched or flat roof (tiled to match existing or modern flat roof)
Windows and doors on both floors
First-fix electrics and plumbing for both levels
Plastering, decorating, and finishing on both floors
Staircase modifications if required
Typical timeline: 10–16 weeks for a standard 4m x 4m double-storey extension.
Typical cost: £1,480–£2,250 per m² (roughly 20% less per m² than single-storey due to shared foundations and roof). A standard 4m x 4m double-storey extension (32m² total) typically costs £53,000–£64,000.
3. Loft Conversions
Loft conversions are one of the most cost-effective ways to add space — transforming unused attic space into bedrooms, bathrooms, home offices, or playrooms.
Types of loft conversions:
Velux (Rooflight) Conversion:
Simplest and most affordable option
No changes to roof structure — just adds roof windows (Velux or similar)
Requires adequate existing head height (minimum 2.2m at highest point)
Typically creates 1 room (bedroom or office)
Usually permitted development (no planning required)
Typical cost: £22,000–£38,000 (£1,200–£1,800 per m²)
Rear Dormer Conversion:
Most popular type in the UK
Adds a box-shaped dormer to the rear roof slope, creating full head height and floor space
Can accommodate 1–2 rooms plus a bathroom
Usually permitted development for terraced/semi-detached houses (check with your council)
Typical cost: £30,000–£65,000 (£1,400–£2,200 per m²)
Hip-to-Gable Conversion:
Ideal for semi-detached or detached houses with hipped roofs (sloped on three sides)
Converts the sloped "hip" end into a vertical gable wall, maximising internal space
Often combined with a rear dormer for maximum space
Usually requires planning permission
Typical cost: £33,000–£70,000 (£1,500–£2,400 per m²)
L-Shape Dormer:
Combines rear dormer with side dormer (over side extension)
Creates maximum floor space — ideal for large families
Typically creates 2–3 rooms plus bathroom
Usually requires planning permission
Typical cost: £55,000–£100,000+ (£1,800–£2,500+ per m²)
Mansard Conversion:
Most extensive type — replaces one or both roof slopes with near-vertical walls
Maximises internal volume and head height
Common in London and urban areas
Always requires planning permission
Typical cost: £55,000–£95,000+ (£2,000–£2,800+ per m²)
What's included in all loft conversions:
Structural steel beams and floor joists
Staircase installation (space-saving designs available)
Roof alterations (dormer construction if applicable)
Roof windows or dormer windows
Insulation to meet current Building Regulations (roof, walls, floor)
First-fix electrics and plumbing
Plasterboarding and plastering
Fire safety measures (fire-rated doors, smoke alarms, escape windows)
Building Regulations approval and completion certificate
Typical timeline: 6–10 weeks for Velux, 8–12 weeks for dormer, 10–14 weeks for hip-to-gable or mansard.
4. Kitchen Extensions & Renovations
Kitchens are the heart of the home — we specialise in creating spacious, functional, modern kitchens that work for your lifestyle
Kitchen extension options:
Single-storey rear extension — create a large open-plan kitchen/dining/family area
Side return extension — ideal for Victorian/Edwardian terraced houses (adds 3–4m width to kitchen)
Wrap-around extension — maximise kitchen and living space with L-shaped extension
Kitchen renovation only — remodel existing kitchen without extending (new layout, units, appliances)
What's included:
Structural work (foundations, walls, roof, steel beams if removing load-bearing walls)
Kitchen design and layout consultation
Supply and installation of kitchen units, worktops, and appliances
Plumbing for sink, dishwasher, washing machine, etc.
Electrics for appliances, lighting, and sockets
Flooring (tiles, engineered wood, LVT — suitable for kitchens)
Lighting design (downlights, pendant lights, under-cabinet lighting)
Bi-fold or sliding doors to garden (if extending)
Plastering and decorating
Typical timeline: 8–12 weeks for kitchen extension, 3–4 weeks for kitchen renovation only.myjobquote
Typical cost: Kitchen extensions £1,650–£2,400 per m² (standard spec), plus £15,000–£40,000+ for kitchen supply and installation depending on quality and size.
5. Full House Renovations
Complete property renovations transform tired, outdated, or poorly configured homes into modern, efficient, beautiful living spaces :
When full renovation makes sense:
You've bought a property that needs modernising (common with period properties)
The layout doesn't work for your lifestyle (small rooms, poor flow, no en-suites)
You want to improve energy efficiency (new insulation, windows, heating system)
The property has structural issues (subsidence, damp, roof problems)
You're converting a property (e.g., barn conversion, office-to-residential)
What's included:
Strip-out — remove old kitchens, bathrooms, fixtures, fittings, and non-structural walls
Structural work — repair or replace roofs, floors, walls, foundations as needed
Rewire — complete electrical rewire to current regulations
Replumb — new plumbing, heating system, radiators, bathrooms
Insulation — upgrade to current Building Regulations (walls, floors, roof)
New windows and doors — double or triple glazing, improved security
New kitchen and bathrooms — design, supply, and installation
Plastering and decorating — throughout
Flooring — throughout (carpets, engineered wood, tiles, etc.)
External works — repointing, rendering, painting, landscaping if required
Typical timeline: 12–24 weeks depending on property size and scope .
Typical cost: £1,500–£3,000+ per m² depending on specification and property type. A full renovation of a 100m² semi-detached house typically costs £150,000–£300,000+ including kitchen, bathrooms, and all finishes .
6. Period Property Renovations
The Cotswolds has many period properties (Victorian, Edwardian, Georgian, and older) that require specialist knowledge to renovate correctly :
Specialist considerations:
Breathable construction — use lime mortar, lime plaster, and breathable paints to allow walls to function as designed
Heritage compliance — listed buildings require Listed Building Consent for most works
Conservation areas — restrictions on external changes (windows, doors, roof materials)
Traditional materials — source matching bricks, stone, tiles, and joinery
Feature restoration — carefully restore original features (fireplaces, cornices, floorboards, staircases)
Modern upgrades — sensitively add insulation, double glazing, and modern heating without compromising character
Our approach:
Assess the property's construction type and condition
Identify original features worth preserving or restoring
Specify appropriate materials (lime mortars, breathable insulation, traditional finishes)
Work with conservation officers for listed buildings
Balance modern comfort with period character
Typical cost: Period renovations often cost 10–20% more than modern properties due to specialist materials and skills required, but they protect and enhance the property's value and character .
Planning Permission vs. Permitted Development
Understanding planning rules can save you time and money:
Permitted Development (No Planning Required)
Many extensions and loft conversions fall under Permitted Development (PD) rights, meaning you don't need full planning permission — but you must still meet specific limits:bestbuilders.co
Single-storey rear extensions:
Can extend up to 4m for detached houses, or 3m for terraced/semi-detached houses (under PD)
Can extend up to 8m (detached) or 6m (terraced/semi) under Prior Approval (neighbour consultation scheme)bestbuilders.co
Maximum height: 4m at the ridge
Must not exceed 50% of the original garden area (combined with other outbuildings)
Double-storey extensions:
Can extend up to 3m from the original house (under PD)
Must be at least 7m from the rear boundary
Maximum height: same as existing housebestbuilders.co
Side extensions:
Single-storey only under PD
Maximum width: 50% of original house width
Maximum height: 4m
Loft conversions:
Velux conversions: usually PD (no roof alterations)
Rear dormers: usually PD for terraced/semi-detached houses (check with your council)
Hip-to-gable, L-shape, mansard: usually require planning
Important: Permitted Development rights may be restricted in:
Conservation areas (common in the Cotswolds)
Areas of Outstanding Natural Beauty (AONB / Cotswolds National Landscape)
Listed buildings (all works require Listed Building Consent)
Properties with Article 4 Directions (removes certain PD rights)
Always check with your local planning authority before starting work.
When You Need Planning Permission
You'll need full planning permission if your project:
Exceeds PD limits (size, height, or position)
Is in a conservation area or AONB with restricted PD rights
Involves a listed building (any external or structural changes)
Changes the roof shape significantly (mansard, large hip-to-gable)
Includes forward of the principal elevation (front extensions rarely allowed under PD)
Your property has already used up PD allowances (previous extensions, outbuildings)
Our advice: Even if your project is PD, consider applying for a Lawful Development Certificate (LDC) (£103) — this provides official confirmation from the council that your extension is lawful, which is valuable when selling the property .
When Extensions & Renovations Are the Right Choice
You'll benefit from an extension or renovation if:
✅ You need more space — growing family, home office, elderly relative, hobby room
✅ You love your location — don't want to move schools, commute, or leave the area
✅ Your property is underperforming — small kitchen, no en-suite, poor layout
✅ You want to add value — well-executed extensions typically add 10–20% to property values
✅ Moving costs are prohibitive — stamp duty, estate agent fees, and removal costs can total £20,000–£40,000+
✅ You want to modernise — improve energy efficiency, update outdated interiors, add modern comforts
✅ You've bought a renovation project — period property or tired house that needs complete overhaul
Not sure if an extension or renovation is right for you? We offer free site surveys — we'll assess your property, discuss your needs, and recommend the best solution (extension, loft conversion, renovation, or a combination).
Why Choose Faber Building for Extensions & Renovations?
🏠 Local Cotswolds specialists — we understand the area, property types, and planning considerations (especially in conservation areas and AONB)
🔧 Fully insured — £5 million public liability cover for your protection
⭐ End-to-end project management — we handle everything from design coordination to final snagging — you have one point of contact throughout
⏱️ Transparent pricing — free quotes within 24 hours, clear breakdowns, no surprises or hidden costs
🧹 Leave it better than we found it — protected surrounding areas, clean work zones, all waste removed
💬 Honest advice — we'll tell you if an extension is feasible, if planning is likely to be approved, and what will give you the best return on investment
🛠️ Quality workmanship — extensions and renovations are major investments — we take pride in work that lasts decades and adds real value
Frequently Asked Questions
How long does a house extension take?
Single-storey extension: 8–12 weeks from start to finish for a standard 3m x 4m rear extension.bestbuilders.co
Double-storey extension: 10–16 weeks for a standard 4m x 4m extension.
Loft conversion: 6–10 weeks for Velux, 8–12 weeks for dormer, 10–14 weeks for hip-to-gable or mansard.
Full renovation: 12–24 weeks depending on property size and scope .
Timelines assume no major delays (weather, planning, or unforeseen structural issues).
Do I need an architect for my extension?
Not legally required for most householder extensions, but highly recommended for:
Complex designs or large extensions
Projects requiring planning permission
Listed buildings or conservation areas
When you want professional design input and full project oversight
For simple permitted development extensions, many homeowners use an architectural technician or design-and-build company (like us) to produce plans and handle Building Regulations — this is more cost-effective than a full-service architect .
Typical costs:
Architect (full service): 5–10% of project value or £3,000–£8,000+
Architectural technician (plans only): £1,000–£3,000
Structural engineer: £500–£1,500 (required for most extensions and loft conversions)
Will my extension add value to my property?
Yes — well-executed extensions typically add 10–20% to property values in the Cotswolds, depending on the type and quality :
Single-storey kitchen extension: Adds 5–10% (kitchens are high-value rooms)
Double-storey extension (extra bedroom + bathroom): Adds 10–15%
Loft conversion (extra bedroom + en-suite): Adds 10–20% (often the best value per m²)
Full renovation of tired property: Can add 20–30% if done to a high standard
Rule of thumb: Don't spend more than 10–15% of your property's current value on an extension if you plan to sell within 5 years. If you're staying long-term, focus on creating a home you love — value will follow.
Can I live in my house during the renovation?
Yes, but it depends on the scope:
Single-storey extension: Usually manageable to stay in the house, especially if the kitchen remains functional
Loft conversion: Minimal disruption — you can usually stay throughout
Kitchen renovation: Possible but challenging — consider setting up a temporary kitchen in another room
Full house renovation: Difficult but possible — we can sequence work to keep one bedroom, one bathroom, and a basic kitchen functional
Double-storey extension: More disruptive — may need to relocate temporarily if the extension affects multiple rooms
We can discuss phasing and temporary arrangements during the quote stage to minimise disruption.
What's the difference between planning permission and Building Regulations?
Planning Permission is about whether you're allowed to build — it considers appearance, impact on neighbours, and compliance with local planning policies .
Building Regulations are about how you build — they ensure structural safety, fire safety, energy efficiency, ventilation, drainage, and accessibility. Building Regulations approval is mandatory for almost all extensions, loft conversions, and structural alterations .
You can have:
Planning but no Building Regs — not allowed (you must have Building Regulations approval)
Building Regs but no Planning — common (many extensions are Permitted Development)
Both — required for larger or more complex projects
We handle Building Regulations applications for all our projects — either through your local council's Building Control or an approved private inspector.
Do you handle the planning and Building Regulations applications?
Yes — we can coordinate the entire process:
Planning applications (if required) — we work with architectural technicians or architects to produce plans and submit applications
Building Regulations — we prepare and submit applications, liaise with Building Control, and arrange inspections at key stages (foundations, damp proof course, insulation, drainage, completion)
Party Wall Agreements — we can advise and coordinate with surveyors if needed
Lawful Development Certificates — we can apply on your behalf for PD projects
You'll have one point of contact throughout — we manage the paperwork so you don't have to.
How do I finance my extension or renovation?
Common options include:
Savings — simplest, no interest
Remortgaging — release equity from your property (often the cheapest option)
Further advance — borrow more on your existing mortgage
Personal loan — suitable for smaller projects (£10,000–£30,000)
Credit cards — only for very small projects or to bridge short-term gaps (high interest rates)
Specialist renovation mortgages — for large renovation projects (release funds in stages as work progresses)
Speak to a mortgage adviser or financial planner to explore the best option for your situation.
Do you offer labour-only services?
Yes — if you've already purchased materials or have an architect producing plans, we can provide labour-only construction. Just let us know during the quote stage. Note: we can't guarantee materials you supply yourself, and we recommend using our supply-and-fit service for best results and warranty coverage.myjobquote
Ready to Transform Your Home?
Get a free, no-obligation quote for extensions and renovations in the Cotswolds, Gloucester, Chipping Norton, or Cirencester area.
📞 Call or text us today — we'll provide a fair quote within 24 hours and arrange a site visit to discuss your requirements.
Local Hands. Local Stone. Local Pride.