Loft Conversion Cost Calculator (UK)

Planning a loft conversion is an exciting way to add space and value to your home. This calculator helps you estimate the potential costs involved based on the type of conversion, size, and location.

How Much Does a Loft Conversion Cost in the UK?

The cost of a loft conversion in the UK typically ranges from £20,000 to £75,000 for basic to high-end projects. A simple Velux or roof light conversion is the most cost-effective entry point, while a large Mansard conversion represents the premium end of the market.

What Affects Loft Conversion Costs?

Several key factors influence the final investment required for your project:

• Conversion Type: Dormer, Hip-to-Gable, and Mansard conversions involve more structural work than roof light options.
• Size & Scale: Costs naturally scale with the total floor area being converted.
• Finish Quality: The choice between basic, standard, and premium finishes can impact the budget by up to 15%.
• Location: Regional labor and material costs vary, with London and the South East typically commanding a 10-20% premium.
• Bathrooms: Adding an en-suite or full bathroom typically adds £4,000 to £7,000 to the total cost.

Is a Loft Conversion Worth the Cost?

Research suggests that a well-executed loft conversion can add up to 20% to the value of your property. For many homeowners, this makes it one of the most financially rewarding home improvements, often providing a significant return on investment while adding essential living space.

Planning Permission and Building Regulations

Most loft conversions fall under Permitted Development (PD), meaning they don't require full planning permission. However, they must always comply with Building Regulations regarding structural integrity, fire safety, and insulation.

Hidden Costs to Consider

When budgeting, it's vital to account for costs that might not be in the initial quote:

• Architect Fees: Usually 3-7% of the build cost.
• Structural Engineer: Required for weight-bearing calculations.
• Party Wall Agreements: If you share a wall with a neighbor.
• Contingency Fund: We recommend setting aside 10-12% for unforeseen issues.

Frequently Asked Questions

How long does a loft conversion take? A typical project takes 6 to 12 weeks, depending on complexity and weather conditions.

Do I need a new roof? Not necessarily, but the existing roof structure will need significant reinforcement to support the new floor and room weight.

Can any loft be converted? Most can, but you need a minimum head height of 2.2m from the top of the ceiling joists to the bottom of the ridge timber.

---

Related Resources

• Dormer loft conversion cost guide
• Loft conversion planning permission guide
• Does a loft conversion add value?

Disclaimer: Estimates are based on UK averages. Final costs vary by property and contractor. We recommend obtaining multiple professional quotes before starting any work.