The mansard is particularly well suited to renovation work on pitched roof houses because the upper story can be enlarged without adding extra height to the structure.
The low downward slope of the mansard roof line acts visually to reduce the scale of a building and helps to eliminate a boxy appearance. This technique is used frequently on large commercial projects, particularly those near residential neighborhoods. It is also a common solution to the problem of avoiding a monotonous appearance on flat-roofed frame apartment buildings.
Properly used, a mansard roof can strengthen the design without substantially increasing construction costs. If raised up above the level of a built-up roof the mansard can screen out roof penetrations or mechanical equipment.
The variety of mansard roofs is practically infinite. One of the most widely used (and misused) roof designs, its proportions and scale are very important and care should be taken to avoid a mansard roof line that is either too skimpy or too generous.
Two of the most widely used roofing materials on the mansard roof are Certi-labelTM cedar shakes and shingles. Cedar shakes, with their heavier texture and solid appearance, are perhaps more frequently specified for mansards although shingles are also used, particularly when a lighter scale is desired.
The light weight and ease of application of Certi-labelTM shakes and shingles contribute substantially to economical construction.
Construction details for typical mansard roofs are shown in Figure 6.