Loft Conversion or House Extension: Which Should I Do First?

Many London homeowners want both a loft conversion and a house extension but are unsure which to tackle first, or whether to do both at the same time. The answer depends on your priorities, budget, property type and how you plan to use the space. LCCL Construction regularly delivers combined loft conversion and extension projects and can advise on the best approach for your situation.

Loft Conversion or House Extension: Which Should I Do First?

Do the Loft Conversion or House Extensions First If You Need Bedrooms

If your main priority is adding bedrooms or a home office, a loft conversion should come first. A loft conversion adds bedrooms on the top floor without losing any garden space, is typically quicker to complete at 8 to 12 weeks of construction, is usually cheaper than a house extension starting from £18,000 for a Velux conversion, and often does not require planning permission under permitted development rights. A loft conversion adding a bedroom with en-suite also delivers the highest percentage return on property value at 15% to 25%.

Do the Extension First If You Need Living Space

If your main priority is a bigger kitchen, open-plan living area or ground floor family space, a house extension should come first. Extensions create the large open-plan kitchen-dining-living areas that modern families need, can completely transform your daily living experience, and directly address the most common complaint London homeowners have about their properties, which is not enough kitchen and living space. A rear extension creating an open-plan kitchen-diner typically costs £40,000 to £80,000 and adds 5% to 10% to property value.

Do Both at the Same Time for Maximum Value

Doing a loft conversion or house extension simultaneously is the most cost-effective and least disruptive approach. You save money because shared costs like scaffolding, skip hire, site setup and project management are paid once instead of twice. You experience disruption once rather than going through two separate construction projects. The combined project can be designed holistically so both elements work together architecturally. And you maximise property value in one go, potentially adding 20% to 35% to your home value. LCCL Construction regularly delivers combined loft and extension projects with a single design and build package.

Cost Comparison

A loft conversion alone typically costs £30,000 to £75,000. A house extension alone typically costs £40,000 to £100,000. A combined loft conversion and house extension typically costs £65,000 to £160,000, which is less than doing both separately due to shared costs. The combined approach also means one design phase, one planning process, one building regulations application and one construction period, saving both time and money. LCCL Construction provides detailed fixed-price quotes for combined projects.

Get Expert Advice from LCCL Construction

LCCL Construction has over 20 years of experience helping London homeowners decide the best approach for their property and budget. We offer free consultations where we assess your property, discuss your priorities, and recommend whether to do a loft conversion first, an extension first, or both together. We have more than 200 reviews rated 4.7 out of 5 and won the LABC Awards Regional Winner 2024. Call 020 8037 7332, email info@lcclconstruction.co.uk, or book at lcclconstruction.co.uk/booking-calendar/free-consultation-call.