When we are asked to build a new house for one of our many customers, we need to know what they intend to do with the roof space when the house is completed and, in particular, whether they want the space to be a habitable part of the house. This is an important question because it will dictate several important aspects of the construction, namely the pitch of the roof, the number of storeys in the overall construction and the roof design.
If the customer wants to make the attic space one that is to be used as a bedroom or other habitable room, the pitch needs to be somewhat greater than the standard 35 degree angle of most domestic properties. This is because a pitch of this level is too low to permit easy occupation of the attic space. An additional pitch of around ten degrees will make the roof space more comfortable but it will also result in the house looking somewhat overshadowed by the roof. We closely consult with our customers about what their preference is and the extent to which they value comfort above appearance and vice versa. There are two alternative options that may enable the provision of a comfortable living space without detracting from the overall appearance of the house.
A One and a Half Storey House
Creating a one and a half storey house can reduce the importance of the roof pitch to the attic space. In simple terms, the roof is built half way up the top storey of the house. Additional implications of this type of roof design are that the lower floor is likely to be around twice the area of the upper floor and will also have a larger roof to wall ratio. The windows in a one and a half storey house are usually dormers and for that reason, coupled with the low elevation of the property overall, houses of this type of design are felt to have a cottage-style fell and to be somewhat more quaint than traditional two storey properties.
A Mansard Roof
A Mansard roof, which is also known as a French roof or a curb roof is an alternative design that provides additional height to a loft space. This is achieved by constructing the roof with two slopes on each of its sides. The lower slope, into which dormer windows are built, is at a steeper angle than the upper slope. The steep roof with windows provides an extra stories of habitable space and reduces the roof’s overall height. Thus, the mansard style makes the most of the available space in the the inside of the loft and, additionally, provides a simple means of adding one or more storeys to a new or existing building without necessarily requiring any extra masonry. Mansard roofs are widely seen in properties in France, from where they are believed to originate, and in the USA.
Providing an additional room or rooms to a house by creating a habitable loft space is an effective way of adding space to a house without adding substantially to the construction costs. Obviously, the greater the amount of living space, the more the property is likely to be valued. Which of the three principal alternatives is chosen depends on the choice of the customer and, to an extent, planning issues. Our Devon roofers are happy to advise you on the pros and cons of the three alternatives and to provide details of the likely impact of each one on the overall cost of constructing the house both in terms of the labour and materials involved.