Dormer Windows: A complete guide

The Average Cost of Dormer Windows

In the UK, a dormer loft conversion can cost anything upwards of around £20k. As a general rule, you can expect to pay around £500 or £600 per metre squared. For a full master bedroom loft conversion complete with an en suite, you will usually expect to pay more, with an average cost of between £35k-£45k. 

Is Planning Permission Required?

Usually, you will not need to get planning permission to add dormer windows to your loft conversion, as long as they do not exceed the highest part of the roof. There may be other specific parameters to meet. The best thing to do if you are planning a dormer loft conversion is to get in touch with your local planning office and let them know about the work that you are planning to ensure that it falls within permitted development rights. You will usually need to get building consent before adding dormer windows that use materials that contrast with the existing property in style, or if you live in a conservation area. 

Different Types of Dormer Windows

The gable-fronted dormer loft conversions are the most popular type. Traditionally, this has a simple pitched roof that slopes on either side. It’s supported by a vertical frame which forms a triangular section underneath the roofline. 

Another option is a shed dormer, which has a single, sloped flat pane that goes in the same direction of the roofline, but the angle is more shallow.  

A hip roof dormer will slope on three planes, converging at one point. 

Finally, the eyelid dormer style is one that emerges gradually as the roof moves up and over the dormer, in a flattened bell curve shape. 

Tips for Getting Your Dormer Windows Right

Many dormers are not original, especially those in period cottages where there would not have been any window openings on the first floor. However, lots can easily be mistaken for being original, as they are the perfect size and in proportion with the roof. When planning dormer windows, one of the most important things to plan to get them right is the proportion. 

Design Mistakes to Avoid

When designing dormer windows, it’s crucial to keep them as an integral part of the overall property design. The design should be relevant to or follow the guidelines of the existing roof shape as much as possible. Going too large with the dormer window, especially on a smaller property, is one of the biggest mistakes that you can make. Avoid adding any features without considering the overall existing design and try to find a style that suits the house. Don’t go too large or too boxy, as this tends to overpower the rest of the house and can be an ugly finish. 

Dormer loft conversions and Velux windows can make a huge difference to both the interior and exterior of your home. One of the most important things to consider when choosing dormer windows is how they fit in with the overall design and look of the property.