Adding a single storey extension can be a great way to create more living space in your home. However, accurately budgeting for an extension project can be tricky. Costs can vary widely depending on the size and features you want. This article will explore the key factors that influence extension costs and provide tips for getting accurate quotes.
Related: Single Story Extension Ideas
Factors That Influence Cost
Many elements contribute to the final cost of a single storey extension. The main factors include:
Size and Scope
The larger the footprint and higher the specifications, the more you can expect to pay. As a rough estimate, a basic 6m x 4m extension with minimal fixtures may cost around £25,000. Larger or more complex builds cost proportionally more.
Carefully define your required size and features upfront. Consider details like:
- Footprint dimensions
- Ceiling height
- Layout (number of rooms, doors, windows etc.)
- Fixtures and fittings (flooring, lighting, kitchen, bathroom etc.)
Get accurate measurements and plans drawn up at the outset. This allows builders to provide precise quotes. It also ensures you get consent for the actual build.
Materials
The materials used can impact the extension cost per m2. Opting for higher end finishes like stone flooring, recessed lighting or luxury fixtures naturally adds to the bottom line. Standard plaster walls with vinyl flooring tend to be the most economical choice.
Consider costs of core structural materials as well, like:
- Concrete for foundations
- Bricks, wood or steel frames
- Roofing tiles or sheets
Factor in aesthetic elements like exterior brickwork types too.
Labor
Builder wages contribute significantly to the total project cost. Opting for a general builder typically costs less than hiring specialists. However, experienced extension builders tend to work faster. This can offset higher hourly rates through efficiency.
Make sure to get an accurate estimate of:
- Total work hours needed
- Hourly labour rate
- Team size
These directly feed into the project quote.
Related: Cost of an Extension
Getting Accurate Quotes
Accurately budgeting for your extension relies on getting precise quotes. Be wary of ballpark figures, ranges or hourly rate estimates. The total spend often far exceeds initial suggestions.
Related: Compare Extension quotes in your area FREE
Online Calculators vs Professional Assessment
Online extension cost calculators only provide very rough estimates. These are based on assumed averages. The unique circumstances of your project can alter costs considerably.
While useful for high-level budgeting, take results with a grain of salt. Instead, get quotes from at least three builders based on your actual plans. This provides a real-world costing for your specific project.
Professional builders will assess on-site conditions too. Consider aspects like:
- Drainage requirements
- Foundation depth
- Accessibility
This prevents unexpected extra costs down the line.
Getting professional guidance early is wise despite the fees. You safeguard your budget against unrealistic estimates that require revision later.
Related: Extension Cost Calculator
Planning Permission Considerations
Whether you need planning consent for your extension plays a role in the cost as well. Permitted development rights have limits requiring careful review.
Extensions exceeding 30m3 in volume, over 4m in height or within 2m of a boundary line often need approval. Consent applications add both time and cost to gain formal permissions.
Securing planning permission also commonly requires:
- Filing proper documentation
- Building regulation consultations
- Surveyor review of plans
- Making changes to accommodate feedback
These contribute to the overall project spend.
Even with permitted extension allowances, consider getting professional support. They guide you on requirements applicable to your property. This prevents unapproved development disputes down the line.
Conclusion and Next Steps
Accurately assessing single storey extension costs lets you set reliable budgets. Now that you know the influencing factors, secure formal quotes for your specific build.
Be sure to get plans drawn up and speak to your local authority. This confirms if consent is required before comparing contractor estimates.
With realistic costing in place, you can progress your extension project with confidence!
FAQs
What is the cheapest way to extend a house?
Opt for a basic layout without complex features or high-end finishes to reduce costs. Prioritise essentials like adequate room dimensions over expensive materials or fixtures.
How long does a single storey extension take to build?
The typical end-to-end timeline is between 8-12 weeks. Larger or more complex projects tend to take longer. Be sure to account for regulatory approvals and weather delays as well.
Should I get planning permission for extension?
Review the permitted development allowances applicable to your property. If your intended extension exceeds the thresholds for size, height or location, getting consent is advisable despite the added time and costs.
What is the most popular extension size?
A 6m x 4m (24 m2) single storey extension is very popular, providing ample extra living space without appearing too imposing. Such additions generally fit within permitted guidelines too when designed appropriately for the home.
Who is best to build a house extension?
Opt for an established general contractor that specialises in domestic extensions. They have the experience to handle all aspects efficiently. Consider reviews and examples of previous extension projects in your decision process.
