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5 ways to reduce your loft conversion costs

Converting your loft space is a great way to add more space to your home, but it can be costly. Homebuilding & Renovating Show share their top five tips for cutting your loft conversion costs.

4 minute read

loft conversion costs

How can you reduce your loft conversion costs?

The costs for a loft conversion will depend on the size, the complexity of the design, who does the building work and the location. If you understand these simple variables and how they impact on cost, you will be able to get a good idea of how much to budget and understand why builders’ quotes can vary so much.

1. Consider smaller to keep loft conversion costs down 

Loft conversion costs are calculated by multiplying the usable gross internal area (the area with headroom of 1.5m or above) by the finished build cost per square metre (£/m2). The cost per square metre will typically vary from around £1,250/m2 to 2,500/m2 depending on the design and on who builds it and where.

Generally the smaller the project, the lower the total cost, but larger projects can end up costing less on average per square metre (£/m2) due to ‘economies of scale’. Be aware, that a very small loft conversion that only creates a small amount of additional useable space – typically because of the limited available area with full height headroom, can be very expensive per square metre and may not be worthwhile doing, especially after deducting the space lost on the floor below to accommodate a new staircase.

2. Choose a simple design

Two of the biggest cost variables in budgeting for a loft conversion are the complexity of the project and the quality of the finishes: the simpler the design, the lower the cost. 

In particular costs rise according to the level of alterations required to the existing property. 

  • Lowest cost: A rooflight conversion that simply involves fitting out the existing roof space, requiring limited structural alterations and the addition of insulation, plumbing and heating, staircase, plaster and decoration, will be the least expensive option. 
  • Mid-Cost: Adding one or more dormer windows to add more usable space will involve more structural alterations and so will typically cost more money, especially if access is limited.
  • Highest cost: A mansard loft conversion, or converting a modern engineered truss roof, can effectively mean replacing the whole of the existing roof structure with an additional attic storey and is the most expensive.

3. Pick off-the-shelf materials

Choice of materials and finishes will also affect cost, with simple off-the-shelf standard rooflights, stairs and standard design details being the most cost-effective, and bespoke windows, stairs and cabinetry all adding significant cost. Choice of fixtures like tiles, sanitaryware, lighting, sockets and switches can be another big variable, with scope to really economise or to splash out on luxury.

4. Manage the project yourself

The simplest option to convert your loft is to hand the project over to a specialist design and build contractor, or to an architect who then helps you find and manage a builder, but there is a cost for paying someone else to manage the project for you and take on the stress. If you have the time and knowledge required to hire subcontractors, buy materials and manage the build, you can reduce costs by 10-20%.

If you have DIY skills, you can reduce labour costs cutting the overall cost by as much as 40%, but only take on what you have the time and skill to complete cost effectively.

5. Choose builders located further afield

Be aware that labour costs vary significantly across the UK, with trades in London and the home counties being amongst the most expensive and the north, east and south west being significantly lower. This feeds through into builder’s prices. Not surprisingly there is a strong correlation between the cost of labour and local living costs, especially house prices. 

The cost for building materials and interiors are similar across the UK, although larger items will have higher delivery costs in more remote parts.

The best guide to costs is to look at similar projects to your own that have recently been completed by other homeowners on sites such as 

Get expert advice at the National Homebuilding & Renovating Show

If you’re looking for further advice or inspiration then the next National Homebuilding & Renovating Show takes place Thursday 24 to Sunday 27 March 2022 at the NEC Birmingham.

Get access to self-build specialists, renovation experts and leading brands all under one roof. Discover the latest products, understand how to maximise your budget or seek an architect’s opinion. From small plots to big builds, the Homebuilding & Renovating Show is the place to pick up tools and tips from the brightest and best in the business.

Get free tickets to the National Homebuilding & Renovating Show

We are offering all HomeOwners Alliance visitors free tickets to the show. Register here for entry for 2 people to The National Homebuilding & Renovating Show. To register for your free pair of tickets, simply complete your details and they will email you your tickets.

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