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Loft Conversions: A Complete Guide


A loft conversion can be an interesting and inexpensive way to increase the amount of usable space in your property. There are, however, a number of different aspects to take into consideration. Have questions about converting your loft or attic? Here’s a guide to everything you need to know about prices, practical aspects of the build, and ideas for what you will be able to do with your extra space once the work is finished. 

Before You Plan a Loft Conversion

If you’re considering a loft conversion, there are some criteria related to planning permission that the space will have to fulfil before you can legally convert your loft from storage space to living accommodations. The most important and potentially troublesome requirement is that the space have at least 2.2 metres of headroom. If this is not the case, then building regulations dictate that you may not use the space as a habitable area. If you find yourself in this situation, there are solutions available to you, although they may prove to be costly and time-consuming. The first of these is to create more headroom by having the roof raised, requiring its complete removal as well as the installation of a temporary measure to prevent water entering your home while the work is being carried out. A roof extension would also require obtaining planning permission. As an alternative, you also have the option of lowering the floor of the loft. Since this work is internal, it doesn’t require planning permission; however, it does require the total removal of the floor of the loft. It’s worth noting that this will be time consuming and will create a significant amount of mess. 

Depending on the type of property you own, you may also be required to comply with the Party Wall Act. In essence, this means that if you share a wall with your neighbour (if you live in a terraced house or a flat, for example), you are required to inform them of the building works you would like to have carried out, such as rebuilding or lengthening a party wall, or other significant alterations. Your neighbour will then be able to lodge an objection to this if they so wish. 

How Much Does a Loft Conversion Cost?

Once you have dealt with the administrative aspects of the construction, it is time to consider the financial side of things. One of the reasons that loft conversions are so popular in the UK is that they allow you to add a significant amount of value to your home without making a huge investment. Despite generally costing between £15,000 and £55,000, converting a loft has been found to add around 20% to the market value of your home, which equates on average to £46,000. Loft conversions are also an advantageous choice for homeowners in large cities such as London where space is limited, as it offers the possibility to increase their living space without extending their property outward.

The exact cost per square metre for a loft conversion can vary significantly depending on each individual case. The price of an attic conversion depends on a number of factors, including your location, the type of conversion, the size and purpose of the space, the type of roof structure, and the quality of the finish. Broadly speaking, the more changes you make to the existing structure, including to the lower floors, the more expensive the conversion will be. Aspects of the loft conversion to factor into your budget include reinforcing the floor, installing windows and electrics, upgrading the insulation, a staircase, lighting, heating and fire safety measures such as smoke alarms. There will also be professional and administrative fees to consider, which may include architects’ fees, planning permission fees, or certificate of lawful development fees if your conversion falls under Permitted Development rights, building regulation fees, and party wall arrangements, which may cost over £900 per neighbour in surveyor’s fees. 

Types of Loft Conversion

There are several types of loft conversion to choose from, depending on your budget and roof type as well as the space you hope to create. A rooflight loft conversion is one of the most simple and affordable options, and in many cases won’t require planning permission. Also known as a VELUX loft conversion, for the brand of roof windows, this type of conversion doesn’t alter the structure of the roof itself but rather utilises the existing attic space to turn it into a habitable living space, such as a bedroom or bathroom. While cheaper, less disruptive and easier to get approved than other options, roof light loft conversions are only a possibility if your house already meets certain requirements, such as sufficient headroom, and also present limitations in terms of designing your space. 

Dormer loft conversions are one of the most popular options to turn a cramped loft into useful living space. There are various styles of dormer available to suit your house, from gabled and arched to flat roof and shed dormers. Dormers can be a great cost-effective solution for lofts that are too small for a rooflight conversion since they create more headroom, and they remain an affordable choice. Many dormer loft conversions fall within permitted development legislation, although you may be required to apply for planning permission, for example if your house is a listed building or in a conservation area, if the height of the dormer exceeds the height of the roof, or if it affects your neighbours. Dormer loft conversions often start at around £35,000, although the cost could be significantly more depending on the complexity and size of your project.

A mansard loft conversion is a more complex option, but can add more headroom and living space than other types of conversion. A mansard is typically added to the rear and is built out from the slope of the roof, with the outer wall typically sloping inwards at an angle of 72°. Popular for terraced houses, a mansard often involves raising the gable wall or party wall, and generally require planning permission. Another option is a hip-to-gable loft conversion, which involves altering the outline of the roof to create a flat gable end. Given the structural changes involved, mansard and hip-to-gable loft conversions will be more expensive than a dormer conversion, but are often considered more aesthetically-pleasing and practical options that can significantly increase the value of your home.