How much does a loft conversion cost? Your budgeting questions answered

All you need to know about transforming your attic space

Converting your loft not only provides more space, it can also add value to your home. But transforming the attic doesn't come cheap. In need of advice on loft conversion costs?  You've come to the right place as we ask the experts to explain the different styles of conversions to suit different properties and how much each option costs. They've got ideas to help budget your build and make savvy savings along the way.

See all of our project planning ideas for all your  home renovation needs

Converting the attic is a highly efficient way of improving rather than moving. 'Interest in loft conversions is increasing as homeowners look to add more space to their properties. At Rated People we’ve seen demand for loft conversions surge by almost a quarter (24 per cent) so far this year, compared to the start of 2020' explains CEO Adrienne Minster.

Smart loft conversion ideas create wonderful light-filled rooms, ideal for comfortable attic bedrooms, living rooms, bathrooms, and home offices.

How much does a basic loft conversion cost?

attic office room with table and shelves

(Image credit: Future PLC/Joanna Henderson)

According to the Royal Institution of Chartered Surveyors (RICS), the cost of the average basic loft conversion equates to one third of the cost of moving to a new property with an extra room. The institution also predicts it could increase the value of your home by approximately 25 per cent.

'The cost of a loft conversion depends on the type of conversion you choose' says Rob Wood, Director of Simply Loft. Explaining the different styles below, to give you a starting point for planning your budget.

  • A skylight conversion starts at £28,000
  • A rear dormer loft conversion begins at £35,000
  • A mansard loft conversion starts at £40,000
  • A hip-to-gable loft conversion at £42,000
  • L-Shaped conversions around £45,000

All of these estimated costings are excluding VAT.

Read more: How to plan a loft conversion - advice for planning and costing your dream space

How to budget for a loft conversion

white bedroom with wall mounted tv and carpet floor

(Image credit: Simply Loft)

'You can alter the price of your conversion by choosing cheaper fittings options, like your windows and doors,' Rob goes on to explain. 'Prices also depend on the size of the loft as houses vary quite dramatically.' Budgeting for your loft conversion all depends on the type of transformation you desire. For example, if no exterior extension is needed it will be cheaper.

But if you’re adding a bathroom or a kitchen this will put up the price due to the extra expertise and labour required. Plumbing and waste for a bathroom can be re-routed from below and the soil pipe extended on the exterior, but your old boiler might not be able to cope with the new demands, so you may need a new boiler which is an expense.

How to cut costs on loft conversions – without cutting corners

'When it comes to house conversions and extensions, prices can vary significantly according to the type of conversion, size, and company you are using' says Ana Delgado at Structural Repairs. 'There are certain things which you can do in order to save money – cutting costs as much as possible, without cutting corners.'

'Conversions and extensions are serious projects which need to be done safely and effectively in order to comply with health and safety regulations. It is not a good idea to attempt to cut costs when it comes to the structural construction of the project' Ana warns.

'However, the best place to save money is in terms of the finishes which you apply to your conversion.'

attic bathroom with washbasin and shower area

(Image credit: Veronica Rodriguez)

'Finishes are the aspects of the project which go beyond the structural and technical elements. This entail aspects such as bathroom or kitchen appliances, finishes and such.'

'While tiles, sinks and baths can be bought from high-end stores for high-end prices, they can likewise be bought from cheaper stores such as B&Q. A bathroom can be fitted from a high-end store for approximately £30,000, in comparison, the same can be done but from B&Q for £350.'

Related: Attic bathroom ideas to make the most of loft conversions of all sizes

'You can also attempt to cut finishing costs by conducting some of the necessary jobs yourself via DIY' suggests Ana. 'Aspects such as painting; wallpapering; hanging curtains; putting up shelves; tiling floors and the like can all be done by yourself which will ultimately cut down costs.'

'A costly part of conversions is the raising or lowering of the ceilings. However, with an appropriate design, you can avoid these costs – while ensuring your living space is as aesthetically pleasing as possible. For example, you can put in some lighting fixtures which are suitable for low ceilings in the sense that they do not hinder headroom and add a visually appealing element to the space.'

Ana goes on to say, 'The furniture layout can likewise be used to create this same desirable result. For example, niche and unique pieces can be placed under low-hanging beams as a means to make use of difficult spaces.'

Unlike alternative extensions, lofts are relatively self-contained in the early stages of building. They can be accessed from the outside – meaning you can continue living in the house while work is underway. Consider this a cost-saving bonus, there are no temporary extra living expenses to factor in.

living space with sofa and cupboard

(Image credit: Future PLC/Simon Whitmore)

Specialist loft companies with their own designers can be the cheapest. Having an architect draw up plans allows you to source different quotes from builders and loft companies.

'When selecting a tradesperson to take on your loft conversion, it’s a good idea to check if they are registered with an official trade body' advises Adrienne Minster, CEO of Rated People. 'Such as The Chartered Institute of Building (CIOB) and the Federation of Master Builders (FMB). And make sure that they have insurance. They will be able to answer any questions you may have. But you can also check the Planning Portal (the government’s online website for planning) for up to date information on regulations, such as fire-resistant doors, structural floors and beams, sound insulation and more.'

Questions you should ask a loft conversion specialist

  • Do they have public liability insurance and what does this cover?
  • Are they registered with an official trade body?
  • Are they registered with a competent person scheme. Will they take care of all planning permissions / building regulation approvals?
  • Do they offer insurance-backed warranties?
  • How long have they been trading for?
  • Can they give you up to 3 references of recent work they’ve completed?
  • Do they use sub-contractors or their own employees?
  • What experience do their sub-contractors/employees have and are they covered by insurance?

attic bathroom with bathtub and brick wall tiles

(Image credit: Brent Darby)

How long does a loft conversion take to complete?

'A loft conversion typically takes between 6-8 weeks to build' says Rob Wood of Simply Loft. 'The design process varies, as this will depend on you obtaining a Party Wall Agreement with your neighbours. That can take several months. And if you need planning permission, it can take up to 8 weeks for your council to approve plans.'


Tamara was Ideal Home's Digital Editor before joining the Woman & Home team in 2022. She has spent the last 15 years working with the style teams at Country Homes & Interiors and Ideal Home, both now at Future PLC. It’s with these award wining interiors teams that she's honed her skills and passion for shopping, styling and writing. Tamara is always ahead of the curve when it comes to interiors trends – and is great at seeking out designer dupes on the high street.