Does a Loft Conversion Add Value? What It Adds and Costs

How much value a loft conversion adds

A loft conversion commonly adds 15% to 25% to a property’s value, according to Checkatrade’s guide to the value a loft conversion adds. An extra bedroom, particularly one with an en-suite, tends to sit at the higher end of that range.

The rise is a share of what your home is worth, so the same percentage is a bigger sum on a more valuable home. As an example using Checkatrade’s range, a rise of 15% to 25% on a home worth £200,000 would be £30,000 to £50,000.

Checkatrade’s cost guide gives a separate figure, saying a well-designed loft conversion can add up to 20% to a property’s value.

What makes a loft conversion add value

The value a conversion adds varies by region, property type and finish quality, Checkatrade’s value guide says. In most cases a loft conversion adds value if it is done to a good standard and suits the local market, while poorly finished or oversized conversions can underperform.

A local estate agent or surveyor can give you a grounded estimate of what a conversion would add to your home, Checkatrade says.

What each type of loft conversion costs and adds

The rise in value has to be set against what a loft conversion costs, and on Checkatrade’s figures most conversions come to £27,500 to £75,000 or more, with many homeowners spending around £50,000.

The averages and ranges below are for a 30m² loft, from Checkatrade’s cost guide, which also sets out what a shell conversion covers. What the other four types add comes from Checkatrade’s guide to the types of loft conversion.

Type	Average	Range	What it adds
Velux (rooflight)	£27,500	£22,500 to £30,000	Windows in the existing roofline, with no added floor space
Shell	£30,000	£22,500 to £37,500	The structural work only: a new floor structure, roof alterations and a dormer if required
Dormer	£50,000	£40,000 to £60,000	Headspace and floor space, from a box structure with vertical windows
Hip-to-gable	£60,000	£50,000 to £70,000	Floor space, by extending the slope of a hipped roof into a vertical gable wall
Mansard	£65,000	£50,000 to £80,000	A roof slope altered to an almost vertical angle, typically at the rear

A Velux conversion is usually the most affordable, and a mansard tends to be the most expensive because of its major structural work, Checkatrade’s cost guide says. A shell conversion leaves the plastering, flooring and decoration to be done separately, so price those in before you set a shell against the rise in value.

Your type of house changes the cost as well as the rise in value. On Checkatrade’s figures, a conversion costs around £50,000 on a terraced or semi-detached house, £62,500 on a detached house and £75,000 on a bungalow. A dormer is the most common option on a terraced house, and on a semi-detached house a Velux or dormer conversion is common.

Is a loft conversion worth it?

On money alone, weigh the rise in your home’s value against the full cost of the conversion, not just the quote. Checkatrade’s cost guide lists architect drawings at £1,000 to £2,000, structural engineer calculations, planning permission fees, party wall agreements and a bat survey at £400 to £750, if one is required, as hidden costs that can add 10% to 15%.

Many homeowners also plan a contingency of 10% to 15% on top of the quote, the same guide says. Its saving tips say most builders recommend around 10%.

Money is not the only reason to convert. Checkatrade’s value guide lists storage, an extra bedroom or bathroom, a home office and better use of wasted space among the reasons, along with better energy efficiency if the insulation is upgraded.

Steps to take before a loft conversion starts

Start by checking whether the loft is suitable for a conversion, which means its ceiling height, its structural capacity and access for a fire escape. Then work through the approvals, the architect, the budget and the quotes before construction begins, Checkatrade’s value guide says.

When you ask for quotes, the Nottingham loft conversion companies compared on guarantees and experience include XL Lofts in Heanor, which has converted bungalows and detached, semi-detached and terraced houses, and Roof Rooms in Ilkeston, which gives a 10-year guarantee covering the structural work and all associated works.