A guide to dormer loft conversions

Loft conversions are a great way to create more space in your home, whether you need an extra bedroom, a study or even a new bathroom. There are several different types of conversion, with a dormer design one of your options.

Here is a brief guide to dormer loft conversions and what you’ll need to consider if you decide to make this kind of alteration to your property.

What is a dormer conversion?

A dormer conversion will stick out from the slope of your roof, with the aim to provide additional headroom in your loft space. These do not need to span the entire length of your roof and can simply be the width of a single window if you choose. It is possible to build dormer conversions with flat roofs – which give the maximum headroom – but those with sloped roofs tend to look more attractive from the outside.

If you decide to go for a larger dormer conversion, be aware there are limits to the volume of space you can add to your loft. For terraced houses, you can’t create more than 40 cubic m of additional room, while this is 50 cubic m for detached and semi-detached properties.

dormer conversion

Will I need planning permission?

Because a dormer conversion will alter the outward appearance of your home, you will usually need planning permission to take on this kind of project. In some areas, you may find dormer conversions are not allowed, or are restricted to the rear of the property, so as not to change the overall look of the street. In other locations, dormer conversions are only allowed at the front of the house, to prevent the new windows overlooking neighbours’ gardens.

You’ll need to speak to your local planning department to find out whether there are any rules or restrictions you need to be aware of before you start work.

Building a dormer conversion: the basics

Opting for a dormer loft conversion will mean you have quite a lot of upheaval while the work is completed. As a general rule, you should expect the scheme to take between four and eight weeks, depending on the complexity of the design.

This isn’t a DIY project to tackle on your own, as you’ll not only need specialist tools and equipment, but also the knowledge to complete the conversion to a high standard and ensure it complies with all the relevant planning legislation and building regulations. Employing a builder to do the job is sensible, as they’ll have the expertise for this kind of work and can organise everything from sourcing materials to hiring a scaffold tower.

Usually, the building process will begin on the roof, with the workers removing the tiling, adding joists and beams and strengthening those already in place. Scaffolding is therefore required to facilitate this and make it safe for the builders to work at height.

Around halfway through the project, work on the interior will begin, such as adding partition walls. Once the external part of the conversion is largely completed, it will be time to create access from the rest of the house to the loft, normally by installing a new staircase. Decorating and adding the final touches will only start once all the major structural alterations have been finished.

Calculating the cost of your dormer loft conversion will depend on a number of factors, including how complex the design is and how large it is. In general, a flat-roofed dormer will cost less than a gable-fronted or hipped-roof dormer, because the structural changes are not as complex. Consult several local builders to get quotes for the work before choosing someone and make sure you plan a margin into your funds for the conversion to allow for any unforeseen expenses.

Writen by Elaine