Most Loft Conversions involve extending to the roof in order to create more usable space within the Loft. There are generally a few different options to consider for each house but if you are just looking for a few ideas here are the most common types of Loft Conversion:
Rear Box Dormers
A Rear Box Dormer is the most common type of Loft Conversion. As the name suggests it involves building a simple box on the back of the roof. This Box Dormer creates a lot of usable space inside the Loft and is relatively straightforward to build. Typically the roof of the Dormer is flat and covered either in Felt, GRP or Rubber Sheet. The walls are normally timber framed and clad in either hanging tiles or slates, or sometimes lead or wood effect boards. If needed the side wall is extended up to form a Gable End and the pitched roof is extended across to meet it, as shown on the house on the left below.
Pocket Dormers and Mansards
Amongst the alternatives to a large Box Dormer is to have a few small Pocket Dormers instead (as shown on the house on the left below). These mini Dormers also help to create extra usable space inside the Loft although not as much as a large Box Dormer would. This is because there is a remaining section of pitched roof between the Pocket Dormers, and either side of them, which cuts into the Loft space. To mitigate this effect you might, depending on the style of house, be able to set the Pocket Dormers inside a Mansard Roof (like the house below on the right). This involves building up the Party Walls at either side of the property (in pink) and building a much steeper pitched roof (in violet) to improve the space in the loft. Pocket Dormers can have either flat roofs or pitched roofs.
L Shaped Dormers for Houses with Rear Additions
Terraced or semi-detached houses often have a small extension at the rear of the building known as the Rear Addition. It’s an original part of the house that now usually houses the kitchen and if it has two stories either a bathroom or bedroom upstairs. In some places the Rear Addition can have a Dormer built over it as well creating the possibility to gain more than one additional room as part of your Loft Conversion.
Houses with pitched roofs to the side of them can benefit enormously from Dormers. A large Box Dormer, as illustrated on the far left, would add a lot of usable space in the Loft whilst a series of small Pocket Dormers would add some space whilst making less of an impact on the overall shape of the building.
Detached houses come in many different shapes and sizes and often the lofts are the most complicated to convert. These images illustrate just a few of the many ways in which a virtual pyramid of pitched roofs can be turned into a viable space by building Dormers and extending walls to form Gable Ends.
Piggy Back Dormers
One of the most unusual type of Loft Conversions is that known as the "Piggy Back" whereby a section of the roof towards the back of the property is raised up in order to create standing room in an otherwise unusable Loft.