A rear dormer extension is the process by which the back slope of the roof is removed and then built up into a box shape from the rear elevation. Rear dormers are usually built off the back wall and up off both the sides.

They are normally finished in either tiles or slates, depending on the style and characteristics of your property.

How is it built?

Dormers are usually built to the full width of the existing property to maximise space and increase the height inside the attic space. Depending on the size of your dormer and location of your property it is possible that you may need to apply for planning permission before Marble Construction can start the building process. Most of the time, however, dormers can be built under permitted development.

The process for building a rear dormer is simpler than most extensions. Many people choose to have a  dormer because of the options it can bring. Space is a key reason for having a rear dormer extension. Whether you need a new bedroom or a study if you’re working from home, the possibilities are endless.

Light is also a good reason for choosing a rear dormer. Velux roof windows let a lot of light into the room and, of course, light is a key ingredient to making a room look and feel spacious. As a rear dormer can technically get light from four different angles (the front, two sides and from above) it makes the room the lightest in the house.

Marble Construction aim to complete your rear dormer in about 6 to 8 weeks but of course this can vary depending on the size and optional extras you can choose to include in the extension.

Are there any eco upgrades?

Yes. With the rear dormer extension comes a number of possibilities in the area of eco products. One of these is some glass mineral wool insulation. This special material is very eco friendly and helpful for keeping your gas bill down. There are many benefits with this material such as the fact it is a great thermal insulator, it is a fire safe material and also a natural product..

How much does it cost?

They come in all shapes and sizes and so it is difficult to put an exact price on them. However, the average price for a rear dormer extension is around £32,000 to £34,000. One thing that may interest you is that many homes are built with a hip-to-gable rear dormer extension. This increases your space even further and only costs an extra £1,000 – £4,000 working out at a total of £33,000 – £38,000.

When it comes to rear dormer extensions there are many things to consider. Many people have a flat roofed dormer which you can see in the first picture. However, if you have a rather tall, instead of doing the flat roof we can construct a much more impressive pitched roof which looks a lot more impressive.

Another thing to consider is what you want to turn the extra space into. Most people go for a master bedroom with an en-suite bathroom. If you are running out of space and have a child on the way then this is the perfect option for you!

Another option is a large study. This can be brilliant if you’re working from home because with the Velux windows you get a great view of the sky and it really brings a calm feeling to the room.

There are also a number of optional extras which can be included in our quotation for you. Velux windows are of course one of them as well as underfloor heating. Another extra which many people go for are French doors. French doors are different from normal doors and the reason for having them is that they look very stylish. They also give you the feeling of the outdoors and they let in more light than normal doors. Another thing to consider is whether you want UPVC windows or not. Why should you choose UPVC windows? Well for a start they are very easy to maintain. They are also brilliant energy savers as the snug and air-tight fit means they provide excellent thermal insulators saving money on your heating bill.

Overall a rear dormer extension with or without a hip-to-gable is an excellent choice if you need more space.

For more information, please see our main page on loft conversions.