How Much Does a Loft Conversion Cost in 2025?

Mariam E.
6 days ago
2 min read

Updated: 5 days ago

A loft conversion is one of the smartest ways to increase your living space and add value to your home. But how much does it actually cost in 2025?

In this guide, we break down average prices, what affects the cost, and how to plan your loft conversion without hidden surprises.

Average Loft Conversion Costs in the UK (2025)

Type of Loft Conversion	Estimated Cost
Velux (Skylight)	£25,000–£35,000
Dormer	£35,000–£55,000
Hip-to-Gable	£45,000–£60,000
Mansard	£55,000–£75,000+
Full Design & Build	£60,000–£90,000+

Costs vary based on location, structure, finishes and access.

What Affects the Price?

Here are some common factors that influence your final cost:

Type of conversion (Velux vs Mansard)
Size and structural layout of your loft
Roof structure (trussed vs cut roof)
Access and new staircase installation
Adding a bathroom or en-suite
Interior finishes and flooring
Planning permission, drawings & building control
VAT and contingency costs

Are There Hidden Costs?

Some often-overlooked items:

Architectural drawings & structural calculations (£1,500–£3,000+)
Building control & inspection fees
Fire safety upgrades (required by UK regs)
Insulation and energy efficiency measures

At Morphos Group, our quotes are detailed and transparent—no surprise add-ons.

How Long Does It Take?

Simple Velux/Dormer: 4–6 weeks
Large or Mansard builds: 8–10+ weeks
Design & planning: Add 4–8 weeks upfront

We handle timelines carefully so you stay informed every step of the way.

What’s the Return on Investment?

On average, a quality loft conversion can add 15–20% to your home’s value. That’s a major return—especially in high-demand areas like London and the South East.