How Long Does a Kitchen Extension Take: A Complete Timeline
Table of Contents
The Full Kitchen Extension Timeline: From Concept to Completion
Kitchen Extension Planning Permission Timeline: What to Expect
Design and preparation phase
Planning application and approval
Building regulations and inspections
House Extension Build Stages: On-Site Construction Breakdown
Site preparation and demolition
Foundations and structural work
Roofing, windows, and exterior finishing
Interior fit-out and kitchen installation
Single-Storey vs Two-Storey Kitchen Extensions: Timeline Differences
Extension Project Schedule Template: Planning Your Kitchen Extension
Pre-construction checklist
Weekly on-site progress tracking
How to Avoid Extension Delays: Risk Management and Contingency Planning
Common delay factors and mitigation strategies
Building contingency into your timeline
Kitchen Disruption and Usability: When Can You Use Your Kitchen Again?
Frequently Asked Questions
Last Updated: October 17, 2026
The Full Kitchen Extension Timeline: From Concept to Completion
A kitchen extension typically takes between 12 to 20 weeks from initial design through to completion, though the total journey from your first idea to moving back into your finished space often stretches to 6-9 months. The variation depends heavily on planning permission timelines, building regulations approvals, and unforeseen site conditions.
The real challenge isn't the on-site construction itself, that's usually 8-12 weeks. The real challenge is everything before the diggers arrive: design, planning applications, building control sign-offs, and material lead times. Most homeowners underestimate this front-loaded phase by at least 4-6 weeks.
Understanding how long does a kitchen extension take means breaking the project into distinct phases. Each has its own dependencies, bottlenecks, and contingency buffers. We'll walk you through each one so you can plan realistically.
Kitchen Extension Planning Permission Timeline: What to Expect
Planning permission is where most projects either accelerate or stall. This phase typically takes 8-14 weeks from submission to decision, but that assumes no complications.
Design and preparation phase
Before you submit anything to the local authority, you need a design. This stage takes 4-6 weeks.
Your architect produces concept sketches, site surveys, and measured drawings. You'll decide on extension size, roof style, materials, and how it connects to your existing kitchen.
Once the concept is locked, your architect produces detailed planning drawings. These show floor plans, elevations, sections, and how the extension sits within the neighbourhood context.
This phase also includes a structural assessment. Your surveyor checks whether the existing house can support an extension at the proposed scale. For two-storey extensions, this becomes critical, you may need steel beams or foundation reinforcement that adds cost and time.
Planning application and approval
Submission to decision typically takes 8 weeks for straightforward extensions, up to 13 weeks if the local authority requests additional information or raises concerns.
You'll submit your planning application with drawings, a design statement, and any supporting documents. The local authority publishes the application, and neighbours have 21 days to comment. This is where party wall agreements become relevant, we'll cover that separately.
If the local authority is satisfied, you receive approval within the standard 8-week period. If they request clarification or amendments, you're looking at another 4-6 weeks of back-and-forth.
Approval doesn't mean you can start building. You've cleared planning, but building regulations approval comes next.
Building regulations and inspections
Building regulations approval takes 3-4 weeks once you submit your detailed technical drawings. These drawings specify structural calculations, materials, insulation values, drainage, electrical routing, and fire safety measures.
The building control officer reviews these for compliance with current Building Regulations. They'll approve in principle, then conduct site inspections at key stages: foundations, structural work, first fix (plumbing and electrics roughed in), and final completion.
This phase overlaps with on-site work, so it doesn't add pure time, but delays here can halt construction. If the building control officer finds non-compliant work, you'll need to remediate before moving forward.
Building Regulations technical guidance sets the standards for structural safety, energy efficiency, and fire protection that apply to all extensions.
House Extension Build Stages: On-Site Construction Breakdown
On-site construction for a kitchen extension typically runs 8-12 weeks. The exact duration depends on extension size, complexity, and whether you're doing single-storey or two-storey work.
Site preparation and demolition
Weeks 1-2 are all about clearing the site and removing existing structures. If you're extending over an existing patio or rear wall, demolition takes 3-5 days. You'll need temporary fencing, skip hire, and dust control measures.
Your contractor will also set up site facilities: a portable cabin for storage, welfare facilities for the workforce, and material drop-off areas. This sounds simple but affects workflow efficiency throughout the project.
If the existing kitchen is still functional during demolition, you can keep using it. Once structural work begins, however, you'll lose access to the rear wall, windows, and potentially utilities like drainage or gas lines that need relocation.
Foundations and structural work
Weeks 2-5 cover the heaviest, most weather-dependent phase. Your contractor digs foundations to the depth specified in structural drawings, typically 1.2 metres for a single-storey extension, deeper for two-storey work.
Concrete is poured and left to cure for 7 days. Then brickwork or blockwork rises to damp-proof course level.
Weather delays hit hardest here. Heavy rain can delay foundation work by days. Frost can compromise concrete cure.
Roofing, windows, and exterior finishing
Weeks 5-8 focus on weatherproofing. The roof structure goes up, tiles or slates are laid, and the extension becomes weather-tight. This is critical, once the roof is on, interior work can proceed regardless of weather.
Windows and external doors are fitted. Brickwork is completed to full height. External rendering or cladding is applied if specified in your design.
This phase has fewer weather dependencies than foundations, so it typically stays on schedule. Lead times for bespoke windows or doors can slip this phase by 1-2 weeks if materials weren't ordered early.
Interior fit-out and kitchen installation
Weeks 8-12 cover plumbing, electrics, plastering, flooring, and kitchen installation. This is where your extension transforms from a shell into a functional space.
First fix (rough plumbing and electrics) happens as soon as the roof is on and walls are up. Then plasterers board and skim walls.
Kitchen installation typically happens in the final 2 weeks. Fitted units, worktops, and appliances are installed once all services are in place and walls are finished.
This phase is less weather-dependent but heavily dependent on material availability. If your kitchen units have a 10-week lead time, they must be ordered before on-site work starts. Delays here are usually material-driven, not site-driven.
Single-Storey vs Two-Storey Kitchen Extensions: Timeline Differences
A single-storey kitchen extension takes 8-12 weeks on site. A two-storey extension takes 12-16 weeks.
Home Extension Guide
The difference isn't just extra height, it's structural complexity. Two-storey extensions require deeper foundations, often steel beams to support the upper floor, and more complex roof structures.
Planning permission is also slightly longer for two-storey work. The local authority scrutinises impact on neighbouring properties more carefully. Expect 10-13 weeks instead of 8-10.
Single-storey extensions are also more forgiving for material delays. If your kitchen units are late, you can still finish brickwork, roofing, and first fix.
For a kitchen extension specifically, two-storey work is less common.
Extension Project Schedule Template: Planning Your Kitchen Extension
Use this template to map your own project timeline.
Pre-construction checklist
Before you contact an architect, complete these steps:
Define your brief: kitchen size, layout, budget, timeline
Get a site survey (measured drawings of your existing house)
Check your planning policy and building regulations requirements
Identify potential party wall issues (extensions within 3 metres of a neighbour's boundary)
Obtain quotes from 2-3 contractors for budget validation
Secure a mortgage offer if you're borrowing (lenders often require planning approval first)
These take 2-4 weeks. Most homeowners skip them and regret it when they hit surprises later.
Weekly on-site progress tracking
Once on-site work begins, track progress against this sequence:
Week | Phase | Key Milestones | Dependencies |
1 | Demolition & site setup | Existing structures cleared, site facilities installed | Weather, utility disconnections |
2-3 | Foundations | Excavation complete, concrete poured, cured | Ground conditions, frost risk |
4-5 | Structural work | Blockwork to DPC, steel beams installed | Beam delivery, brickwork pace |
6-7 | Roofing & weatherproofing | Roof structure complete, tiles laid, windows fitted | Weather, material delivery |
8-9 | First fix services | Plumbing & electrics roughed in, plastering starts | Material availability |
10-11 | Second fix & finishes | Plaster dried, radiators fitted, flooring laid | Plaster drying time |
12 | Kitchen installation & final works | Units fitted, appliances installed, final inspections | Kitchen unit delivery |
This assumes no delays. Most projects slip by 1-2 weeks during structural or roofing phases.
How to Avoid Extension Delays: Risk Management and Contingency Planning
The average kitchen extension slips by 2-4 weeks. Understanding why, and planning for it, is the difference between a smooth project and a stressful one.
Common delay factors and mitigation strategies
Material lead times are the biggest culprit. Steel beams, bespoke windows, and fitted kitchens often have 8-12 week lead times.
Weather delays cost 1-2 weeks on most projects. Heavy rain, frost, or snow halt foundation work, brickwork, and roofing.
Building control inspections can delay work if the inspector finds non-compliant work.
Party wall disputes can stall projects by 4-8 weeks if neighbours object.
Existing structural issues sometimes emerge once work starts. Subsidence, dry rot, or weak foundations can require remedial work that wasn't budgeted.
Utility relocations (gas, water, electrics) can slip by 2-4 weeks if the utility company is slow to disconnect or reconnect. Request these early and follow up regularly.
Building contingency into your timeline
Add these buffers to your schedule:
Design phase: Add 2 weeks for client feedback loops and design revisions
Planning phase: Add 2-3 weeks for potential local authority requests or amendments
On-site work: Add 2-4 weeks for weather, inspections, and material delays
Overall project: Expect 6-9 months from first idea to completion, not 4-5 months
If you're planning a specific date (school holidays, a house sale), build your timeline backwards and add 4 weeks as a safety margin. Projects that run on time feel like a bonus, not a surprise.
Kitchen Disruption and Usability: When Can You Use Your Kitchen Again?
This is the question every homeowner asks: when can I cook again?
Your existing kitchen becomes unusable once structural work begins, typically week 2-3.
Most homeowners go 8-10 weeks without a functional kitchen during the structural and first fix phases.
The new kitchen becomes usable in week 12, once units are fitted and appliances are connected.
Plan for 10-12 weeks of kitchen disruption. This is where good project management matters.
How long does a kitchen extension take depends on planning timelines, building regulations approvals, and on-site construction complexity.
At Sd Architecture, we handle planning applications, building regulations submissions, site supervision, and coordination with contractors so you're not juggling multiple parties.
Frequently Asked Questions
How long does a kitchen extension take to build on site?
On-site construction for a single-storey kitchen extension typically takes 8 to 16 weeks, depending on size and complexity. A two-storey extension can take 20 to 28 weeks. This covers site preparation, foundations, structural work, roofing, windows, plumbing, electrical work, plastering, and kitchen installation. Weather delays and unexpected issues on site can extend this period. The total project duration from initial concept to completion is usually 12 to 18 months when you include design, planning permission, building regulations approval, and procurement of materials.
What causes kitchen extension delays?
Common delay factors include planning permission objections from neighbours, building control inspection failures requiring remedial work, late delivery of materials or bespoke kitchen units, structural issues discovered during excavation, party wall agreement disputes, poor weather affecting foundations and brickwork, and contractor availability. Unexpected ground conditions, gas or electricity relocation, and plumbing or drainage complications also cause setbacks. Building a 20% contingency buffer into your timeline helps absorb these delays without derailing your project.
When can I use my kitchen again during an extension?
Your kitchen becomes unusable once demolition begins, typically at week 2 to 3 of on-site construction. You will not have full kitchen access until the final stages of interior fit-out and kitchen installation, usually 12 to 14 weeks into the build for a single-storey extension. Temporary kitchen facilities (a portable kitchen or arrangement with family) are essential during this period. Plumbing and electrical connections happen in the first-fix phase (weeks 6 to 8), but the kitchen cannot be used until second-fix work, plastering, and appliance installation are complete.
How long does planning permission take for a kitchen extension?
Planning permission typically takes 8 to 12 weeks from submission to decision. This assumes no objections from neighbours or the local planning authority. If your application is called in for further review or neighbours lodge formal objections, the process can extend to 16 to 20 weeks. Building regulations approval, which runs in parallel, takes 4 to 6 weeks for initial submission and a further 2 to 4 weeks after on-site work begins for inspections at key stages. Party wall agreements must be served 2 months before work starts if your extension affects a neighbour's property.
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