1. Introduction: A Common Bexley Homeowner Decision
Living in Bexley (DA5) often means enjoying established neighbourhoods, good transport links, and long-term roots in the area. From period homes close to Bexley Village, to family homes near Hall Place and Gardens, and residential pockets bordering River Cray, many properties have layouts that can be improved without changing location.
One decision comes up time and again:
Is a single-storey extension or a double-storey extension the right solution?
This choice affects build cost, disruption during works, how the home functions afterwards, and the level of value added. This guide is written for Bexley homeowners who want a clear, balanced comparison based on realistic costs, local planning considerations, and long-term suitability.
2. What Is a Single-Storey Extension?
A single-storey extension creates additional space at ground-floor level only. In Bexley, rear extensions are particularly common, especially on semi-detached and detached homes with mature gardens.
Common Bexley Use Cases
- Enlarged kitchen and dining spaces
- Kitchen extensions with rooflights or wide rear doors
- Utility rooms or informal family areas
Why Homeowners Choose This Option
- Lower initial construction cost
- Shorter build programme
- Often achievable under permitted development
- No changes required to upstairs rooms
When It Works Well
- Bedroom numbers already suit the household
- Garden depth allows expansion without feeling restrictive
- The focus is improving daily living rather than adding bedrooms
When It Does Not
- Additional bedrooms or bathrooms are needed
- Garden space is already limited
- The home has scope to increase in value but lacks space upstairs
3. What Is a Double-Storey Extension?
A double-storey extension increases internal floor area across both ground and first floors, usually to the rear or side.
Typical Layouts in Bexley
- Kitchen or family room below with bedrooms above
- Ground-floor living space with an upstairs bathroom or ensuite
- Rear-and-side extensions on wider plots
Why Homeowners Consider It
- Adds bedrooms and bathrooms alongside living space
- Better efficiency per square metre
- Strong appeal for families planning to stay long term
When It Makes Sense
- Growing households
- Homes with limited garden depth
- Properties sitting below the local value ceiling
4. Cost Comparison in 2026: Bexley Context
Single-Storey Extension Costs
- Typical range: £2,300–£3,400 per m² in London and the South East
- 20m² extension: £50,000–£70,000
- 30m² extension: £65,000–£100,000+
Double-Storey Extension Costs
- Typical range: £2,200–£3,000 per m²
- 40m² total (20m² per floor): £90,000–£130,000+
- 60m² total: £115,000–£180,000+
Why Double-Storey Can Offer Better Value
Groundworks, foundations, and structural elements support both floors. This often reduces the average cost per square metre, even though the total project spend is higher.
5. Space and Practical Use Comparison
Single-Storey Extensions
- Maintain the existing first-floor layout
- Reduce garden size more noticeably
- Ideal for improving everyday living
- Less disruption to bedrooms during construction
Double-Storey Extensions
- Provide a significant increase in usable space
- Preserve more garden relative to space gained
- Allow layouts to adjust as household needs change
- Longer and more complex construction period
Short-term disruption is greater with double-storey projects, but many Bexley homeowners find the long-term benefit worthwhile.
6. ROI and Property Value Impact in Bexley
Single-Storey ROI
- Typical uplift: 5–10%
- Kitchen-focused designs can reach up to 15%
- Most effective where layouts were previously inefficient
Double-Storey ROI
- Typical uplift: 10–20%
- Additional bedrooms and bathrooms perform best
- Family homes see the strongest response
In Bexley, buyers prioritise bedroom numbers and usable layouts. A carefully planned double-storey extension often outperforms a large but poorly arranged single-storey build.
7. Planning Permission and Regulations in Bexley
Planning rules vary by street, property type, and designation across Bexley.
Key Points to Understand
- Many single-storey extensions fall under permitted development
- Some double-storey extensions may also qualify
- Conservation areas apply in parts of Bexley
- Article 4 Directions affect certain streets
- Plot-specific constraints can vary significantly
Early planning advice helps confirm feasibility before design costs increase.
8. Common Mistakes Bexley Homeowners Make
- Choosing the lowest quote without checking inclusions
- Designing only for current needs
- Poor consideration of natural light flow
- Underestimating total project costs and VAT
- Forgetting to assess heating and boiler capacity
- Creating layouts that limit future resale appeal
- Exceeding the local property value ceiling
Most of these issues are easier to avoid early than to fix later.
9. Which Option Is Right for You?
A single-storey extension may suit you if:
- Budget is under £80,000
- You want improved ground-floor living space
- Height restrictions apply
- Bedroom numbers are already sufficient
A double-storey extension may suit you if:
- Extra bedrooms or bathrooms are required
- Long-term value growth matters
- Garden space is limited
- Your home has scope to improve local value
So, which is better in Bexley?
There is no single answer. For lifestyle-led upgrades, single-storey extensions often work well. For future planning and stronger returns, double-storey extensions usually offer more flexibility.
10. How Buildaway Can Help
Buildaway works with Bexley homeowners across DA5, delivering both single and double-storey extensions.
We offer:
- Planning-led advice tailored to your property
- Clear cost comparisons and value guidance
- Design-focused solutions rather than standard layouts
- Full project management from drawings to completion
- Local experience with Bexley planning considerations
If you want clear, professional guidance without pressure, we are happy to help.
Ready to Discuss Your Bexley Extension?
📞 020 8108 0388
📧 info@buildaway.co.uk
🌐 www.buildaway.co.uk
Buildaway — helping Bexley homeowners extend with confidence, clarity, and long-term value.