Crawley Extension Planning Guide 2026 | Home Extensions West Sussex
Is your Crawley home feeling a bit cramped? Whether you’re expecting a new arrival, working from home more often, or simply need more living space, a home extension could be the perfect solution. Before you consider the upheaval and expense of moving, extending your current property might give you exactly what you need while adding significant value to your home.
In this guide, we’ll walk you through everything you need to know about planning a home extension in Crawley, from initial concepts to completion.
Why Extend Rather Than Move?
Many Crawley homeowners find that extending offers several advantages over relocating:
Financial benefits: With stamp duty, estate agent fees, removal costs, and the current competitive housing market in Crawley and the surrounding West Sussex area, moving can be expensive. A well-planned extension often costs considerably less while adding substantial value to your property.
Stay in your community: If you love your neighbourhood, your children’s schools, or your proximity to Crawley town centre or the train station, an extension lets you stay exactly where you are while getting the space you need.
Create your ideal home: Rather than compromising on a new property, an extension allows you to design exactly what you want, tailored to how your family lives.
Popular Extension Types in Crawley
Single-Storey Rear Extensions
The most common type of extension we build in Crawley, single-storey rear extensions are perfect for creating open-plan kitchen-diners or adding a garden room. These extensions typically blend seamlessly with your existing home and make the most of your outdoor space.
Two-Storey Extensions
If you need significant additional space, a two-storey extension gives you more for your investment. Popular configurations include adding a master bedroom with en-suite above an extended kitchen, or creating additional bedrooms for a growing family.
Side Extensions
For properties with space alongside, side extensions can be ideal for widening your kitchen, creating a utility room, or adding a downstairs WC. These are particularly popular on semi-detached homes in Crawley’s residential areas.
Loft Conversions
While not strictly an extension, converting your loft space is an excellent way to add a bedroom, home office, or playroom without extending your property’s footprint. Many Crawley homes have generous roof spaces perfect for conversion.
Understanding Planning Permission in Crawley
One of the first questions homeowners ask is whether they’ll need planning permission. The answer depends on several factors:
Permitted Development Rights
Many extensions fall under permitted development rights, meaning you won’t need full planning permission. Generally, you can build:
- Single-storey rear extensions up to 6 metres (detached houses) or 3 metres (semi-detached or terraced houses)
- Extensions no higher than 4 metres
- Two-storey rear extensions up to 3 metres from the original house
However, these rights don’t apply if your property is listed, in a conservation area, or if previous extensions have used up your allowance.
When You’ll Need Planning Permission
You’ll typically need to submit a planning application to Crawley Borough Council if:
- Your extension exceeds permitted development limits
- Your property is listed or in a conservation area
- You’re extending towards the front of your property
- Your extension would be higher than the existing roof
The planning team at Crawley Borough Council is generally helpful, and we work with them regularly to ensure applications have the best chance of approval.
Building Regulations
Even if you don’t need planning permission, you’ll always need Building Regulations approval. This ensures your extension meets standards for structural integrity, fire safety, insulation, and accessibility. As experienced Crawley builders, we handle all Building Regulations submissions and inspections as part of our service.
The Extension Planning Process
Step 1: Define Your Needs
Start by considering exactly what you want to achieve. Are you looking for more living space, better flow between rooms, improved natural light, or additional bedrooms? Think about how you use your home currently and what’s missing.
Step 2: Set a Realistic Budget
Extension costs in Crawley vary depending on size, specification, and complexity. As a rough guide, single-storey extensions typically range from £1,500 to £2,500 per square metre, while two-storey extensions can be more cost-effective per square metre but obviously involve a larger total investment.
Remember to budget for:
- Design and architectural fees
- Planning and Building Regulations fees (if required)
- Construction costs
- Interior finishing and decoration
- Temporary accommodation if necessary
- A contingency of 10-15% for unexpected issues
Step 3: Choose Your Builder
Selecting the right local builder is crucial. Look for:
- Local experience in Crawley and knowledge of local building requirements
- A strong portfolio of completed extensions
- Positive references from previous clients
- Proper insurance and guarantees
- Clear, detailed quotations
- Good communication throughout the project
Step 4: Design Your Extension
Work with your builder or an architect to create plans that suit your needs, complement your existing home, and work within your budget. Good design considers:
- How the home extension will flow from existing rooms
- Natural light and window placement
- Materials that match or complement your current property
- Future-proofing for changing family needs
- Energy efficiency and sustainability
Step 5: Obtain Necessary Approvals
Your builder should help you determine what permissions you need and can often handle applications on your behalf. The process typically takes:
- Building Regulations: 4-6 weeks
- Planning Permission (if required): 8 weeks for standard applications
Step 6: Construction
Once all approvals are in place, construction can begin. A typical single-storey extension takes 8-12 weeks, while two-storey extensions usually require 12-16 weeks. Your builder should provide a clear timeline and keep you updated on progress.
Key Considerations for Crawley Homeowners
Garden Space
Crawley properties vary enormously in garden size. Before planning your extension, consider how much outdoor space you’re willing to sacrifice. Remember that you’ll still need adequate garden access and that some buyers value garden space highly.
Listed Buildings and Conservation Areas
Parts of Crawley, particularly around the historic High Street and St John’s Church, have special planning considerations. If your property is listed or in a conservation area, you’ll face stricter requirements and may need specialist advice.
Party Wall Agreements
If your extension will be built on or near a boundary with a neighbour’s property, you may need a party wall agreement. This is a legal requirement that protects both you and your neighbour, and most projects proceed smoothly once the agreement is in place.
Utilities and Services
Extensions sometimes require relocating gas metres, drainage systems, or electrical supplies. An experienced local builder will identify these issues early and factor them into your project timeline and budget.
Maximising Value from Your Extension
To ensure your extension adds maximum value to your Crawley property:
Quality over quantity: A well-built, beautifully finished extension will add more value than a larger but poorly executed one.
Keep it proportionate: Your extension should suit the size and style of your property and neighbourhood. An overly ambitious extension on a modest property may not give you the return you expect.
Focus on popular features: Open-plan kitchen-diners, en-suite bathrooms, and home offices are particularly desirable in the current market.
Don’t over-extend: Avoid using up all your garden space or creating a home that’s significantly larger than others in your area, as this can actually limit your potential buyer pool.
Common Mistakes to Avoid
Choosing the cheapest quote: The lowest price often reflects shortcuts that will cost you more in the long run through delays, poor workmanship, or unexpected costs.
Inadequate planning: Rushing into construction without proper planning can lead to designs that don’t work for your lifestyle or miss opportunities to maximise space and light.
Ignoring neighbours: Poor communication with neighbours can create tension and even legal issues. Keep them informed and address any concerns early.
Underestimating disruption: Extension work is messy and noisy. Plan for the impact on your daily life and consider whether you’ll need to stay elsewhere during certain phases.
Is an Extension Right for You?
A home extension is a significant investment, but for many Crawley families, it’s the ideal solution. It can give you the space you need, add substantial value to your property, and allow you to create your perfect home without the stress of moving.
The key to success is careful planning, choosing the right builder, and having realistic expectations about timelines and budgets. With the right approach, your extension can transform how you live and significantly enhance your enjoyment of your home.
Ready to Start Your Extension Project?
If you’re considering a home extension in Crawley, we’d love to discuss your ideas. With years of experience building extensions throughout Crawley and the surrounding areas, we can help you navigate the planning process, create a design that works for your family, and deliver a high-quality extension that you’ll love for years to come.
Get in touch today for a free, no-obligation consultation and quote. We’ll visit your property, discuss your requirements, and provide honest advice on what’s possible within your budget. Let’s work together to create the space you need in the home you love.
Crawley Building is a trusted local builder serving Crawley and West Sussex. We specialise in home extensions, renovations, and new builds, delivering quality craftsmanship and excellent customer service on every project.