Loft Conversion Guide: Planning Permission & Costs

Abel Hinchliffe
Loft Conversion Guide: Planning Permission & Costs

Loft conversions are a great way to add space and value to your home without having to move. Whether you need an extra bedroom, playroom or office – converting your loft is a great way to extend your living space.

As every home is individual there are many different elements to take into account. It can be a complicated process. But never fear – this loft conversion guide will take you through all the important parts of a loft conversion and what you need to consider.

Do you need planning permission for a loft conversion?

It’s essential that you find out the answer to this question before you go any further. If you are planning a build or conversion and don’t confirm whether you need planning permission – chances are you’ll run into trouble. And you could even be told to get rid of your loft conversion if you go ahead without checking first.

Contact your local council and find out if your plan is a permitted development or not. If your loft conversion is a permitted development, then you can get on with your build as planning permission isn’t needed.

The types of projects where loft conversion planning permission isn’t needed include:

  • The additional space is less than 50 cubic metres
  • Your building has always been a residential one
  • The pitch on your roof will stay the same
  • There aren’t any existing added storeys
  • The loft conversion doesn’t have a window on the side of the house

How to get loft conversion planning permission

If you find that your planned loft conversion doesn’t meet the criteria above, then it’s likely that you do need planning permission. In order to get it, you can apply to your council for a Lawful Development Certificate.

This is a legal document from the local planning authority that clarifies what permissions are needed when altering or building a property. It is good to have as it can give peace of mind over whether your plans are lawful or not. If you do need planning permission, you will then need to notify your local council exactly what your project entails – type, size and location of your loft conversion.

Types of loft conversion

There are five main types of loft conversion skylight loft conversions, dormer loft conversions, hip to gable loft conversions and mansard loft conversions. The most suitable type of loft conversion for your needs will primarily be influenced by your property's style and your budget. Additionally, it's essential to consider your existing roof structure and be mindful of any planning restrictions that may apply in your local area.

Skylight Loft Conversion:

A cost-effective option that introduces skylights to brighten up the loft space with natural sunlight, creating a warm and inviting ambiance without major structural changes. Perfect for smaller spaces or those on a budget, such as creating a cozy home office or an extra bedroom.

Dormer Loft Conversion:

Dormer conversions project vertically from the roof slope and use standard windows to increase the useful floor area and headroom. They come in various styles, including single, double, or full-width dormers, suitable for expanding families or incorporating larger rooms.

Hip to Gable Loft Conversion:

This type extends the side roof to a gable end, providing more space and allowing for practical room layouts. Ideal for homes with hipped roofs, like many semi-detached houses, and offers flexibility in designing bedrooms or home offices.

Mansard Loft Conversion:

A grand transformation that replaces the sloping roof with a nearly vertical wall, creating a generous internal space with increased headroom. Though one of the more complex and expensive options, it adds significant value to your home and is perfect for various property styles.

L-Shaped Loft Conversion:

Tailored for properties with rear extensions, L-shaped conversions involve a dormer with one end extending from the main roof. This type allows for bedrooms with separate bathrooms and offers ample storage space, making it a versatile and practical choice.

Factors that affect loft conversion costs

A typical loft conversion can cost around £60,000 or more. You might wonder how this breaks down in terms of costs, so have a look at the factors that affect the prices involved:

  • Size of your loft
  • Existing roof structure
  • Type of loft conversion
  • Style and level of specification
  • Length of time taken

Example loft conversion costs

Obviously, every home is different and so every loft conversion won’t be the same. But average loft conversion costs can be worked out based on the type of house and type of conversion.

Generally, you can expect to pay around £60-£80k for a new loft conversion, with some projects costing upwards of £100k depending on the size of the space being converted and the quality of finish. Below are some ball-park figures for popular loft conversion types based on an average 45m2 space…

  • Skylight loft conversion – £50,000 to £90,000
  • Mansard loft conversion - £65,000 to £110,000
  • Hip to gable loft conversion - £65,000 to £120,000
  • Main dormer loft conversion - £60,000 to £100,000
  • L shaped dormer conversion - £70,000 to £120,000
  • Hip to gable with main dormer – £80,000 to £150,000

Note: The estimates provided above don’t include VAT or the cost of fittings or glazing. You’ll also have to consider legal costs and professional fees, which we’ll outline below…

How do the costs break down?

Loft conversions aren’t an out-of-the-box installation. Instead, the cost comprises lots of different factors and parties, with a typical break down as follows:

  • Contractors - 30%
  • Materials - 20%
  • Glazing - 15%
  • Fittings - 5%
  • Structural Engineers - 4%
  • Surveyors - 3%
  • Architects - 2-7%
  • Administration fees - 1%
  • Additionally, VAT – 20%

1. Flooring

Popular flooring choices are vinyl, wood, carpet and tiled. Per m2, you would expect to pay between £10 - £100, depending on your preference.

2. Insulation

Insulation is clearly extremely important when it comes to a new loft conversion. You can choose from sheet and blanket insulation – up to £30 per m2. Or loose-fill insulation – up to £15 per m2.

3. Stairs

Basic staircases can cost between £1,500 - £2,500. Stairs with a more unique style will cost closer to £5,000 - £10,000.

4. Labour

Labour costs will be one of the biggest expenses you will encounter. As you will need a wide range of different professionals to do the work, the overall price can rise very quickly. Hourly rates for tradespeople are usually around £25 - £35 per hour for plasterers and decorators. You are likely to pay a bit more for electricians and plumbers.

5. Surveying, planning, building regulations and architectural fees

It's essential to factor in the various costs associated with the initial stages of the project. Surveying fees cover the assessment of your loft's structural integrity and provide crucial information for the conversion process. Planning fees encompass any necessary applications to local authorities to obtain planning permission if required. Building regulations fees involve ensuring the loft conversion meets safety and construction standards. Architectural fees account for the professional expertise needed to design the conversion and create detailed plans. These costs vary depending on the complexity of the project and your location but you can expect that 10-15% of your budget will go towards these costs.

Don’t forget that there are likely to be a few additional costs such as moving the water tank, painting exterior of house or a bit of cladding and rendering. It’s important to set aside a contingency amount for all the little jobs that can pop up.

DIY loft conversion guide

If you’re feeling brave and want a project, you could reduce costs by doing a DIY loft conversion or part loft conversion. Hire professionals to create the shell (stairs, flooring and wall) and then do the rest yourself. This could save you approximately £10,000, bringing the average cost down to £30k.

This option could suit some people with building experience and the time to do it themselves. But for those who are new to DIY conversions, using a professional team is a much smarter and smoother way to get the best results.

Get your dream loft conversion with CODA Bespoke

If you want to transform your loft into the ultimate additional living space or bedroom, contact CODA Bespoke to get expert advice and a realistic quote.

Our RIBA-accredited professional architects will design a luxurious, unique space that suits your home and lifestyle. Our team can also guide you through the entire project, making sure everything runs smoothly.

Contact CODA Bespoke today and our friendly, experienced team can talk through your requirements. Or browse our portfolio to take a look at some of our recent projects.

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Abel Hinchliffe

With a wealth of experience Abel heads up CODA Bespoke, specialising in luxury residential developments both large and small. Recently entrusted with the responsibility of also heading up Studio 4 which is currently delivering numerous office to residential developments. Connect with Abel Hinchliffe on LinkedIn >

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