How Much Does a Loft Conversion Cost? UK Price Guide

If you are planning a loft conversion in Birmingham, Solihull, Warwickshire or the Black Country, the first question is almost always the same: what will it cost? The honest answer is that it depends on the type of conversion, the size of the loft, the structural work involved and your property itself. This guide sets out the typical cost ranges reported by independent UK sources, the main factors that move the price up or down, and how Carter LS turns that into a firm, itemised written quote for your project.

Typical loft conversion costs in the UK

In 2026 the average loft conversion costs around £50,000 in the UK, according to Checkatrade, as reported by the HomeOwners Alliance (HomeOwners Alliance). That single average hides a wide spread, though: the HomeOwners Alliance also states that the cost can vary considerably depending on the type of loft conversion, the size, the complexity of the project and your property's location (HomeOwners Alliance).

Breaking the average down by conversion type, the HomeOwners Alliance reports the following national averages:

• The average cost of a Velux loft conversion is £27,500 (HomeOwners Alliance).
• The average cost of a dormer loft conversion is £50,000 (HomeOwners Alliance).
• The average cost of a hip to gable loft conversion is £60,000 (HomeOwners Alliance).
• The average cost of a Mansard loft conversion is £65,000 (HomeOwners Alliance).

These are national averages from a third party, not Carter LS prices, and they will move with your region, your roof shape and what you want from the finished room. Treat them as a starting point for budgeting conversations, not a quote.

What actually changes the price

A handful of factors tend to explain most of the difference between a modest Velux conversion and a full Mansard rebuild:

• Roof type and structural work. Raising a ridge, altering a hip end to a gable, or rebuilding a roof slope for a Mansard all add scaffolding, structural engineering and construction time compared with simply fitting rooflights into an existing roof void.
• Dormers and floor area. A dormer extension adds usable headroom and floor space but means more external building work, roofing and weatherproofing than a rooflight only conversion.
• Staircase and layout changes. Fitting a new staircase, especially where it affects an existing landing or bedroom layout, adds carpentry, structural and sometimes party wall considerations on terraced and semi detached homes.
• Plumbing and electrics. Adding an en suite or extra sockets and lighting circuits brings in additional trades beyond the core structural and roofing work.
• Insulation, fire safety and building regulations compliance. A habitable loft room needs to meet current building regulations for insulation, structural strength, escape routes and fire separation between floors, which is factored into the build rather than being optional.
• Access and site constraints. Narrow side access, limited space for skips and scaffolding, or working around an occupied household can all affect how a project is priced and sequenced.

Planning permission and permitted development

Many loft conversions do not need full planning permission. The HomeOwners Alliance notes that loft conversions can be completed within permitted development rights, and that by doing so you will avoid the time and costs involved in seeking planning permission (HomeOwners Alliance). Whether your specific project qualifies depends on factors such as the size of the extension, your property type and any existing extensions, so it is worth checking the detail before you budget on that basis. Our guide on planning permission versus building regulations covers the distinction in more depth, and Carter LS will confirm the position for your specific property as part of your written quote.

How Carter LS prices a loft conversion

Carter LS manages loft conversion projects personally, with one point of contact coordinating the specialist subcontractors involved in the structural, roofing, electrical and finishing work. Rather than a ballpark figure, you receive an itemised written quote that sets out the scope of work, with any changes agreed in writing as the project progresses. The free quoting survey that starts this process is not a structural survey, and any eligibility for a discount on higher value replacement or installation work is confirmed in that written quote rather than quoted upfront.

To see how a loft conversion is typically scoped before pricing, read our loft conversions service page. If you are local to Birmingham, Solihull, Sutton Coldfield or Warwick, those pages set out area specific detail. When you are ready for figures against your own roof and layout, book a free quoting survey and we will put together an itemised written quote.