This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
Next to the simple lean-to roof with a single sloping surface comes the ordinary pitch or gable roof, which has two sloping surfaces one on each side of the center line of the building, coming together at the ridge in the middle. This form of roof, which is shown in Fig. 163, is very common and is also quite simple in design, and economical in construction, so that it has been very popular indeed for all classes of buildings except very large structures and city buildings. The slope of the roof, that is, its "pitch" or its inclination to the horizontal, may be varied to an infinite extent, from a very flat slope to a very steep one, and these variations have been made in different countries and in different climates to suit either the taste of the designers or the practical requirements of the climate. The roof may be used in combination with roofs of other kinds and, indeed, it is usually used in this way, so much so that, although the simple gable roof is the base of almost all the roofs of ordinary structures, it is sometimes hard to distinguish it from among the other roofs which have been added as additions to it.
Fig. 1C3. Pitch or Gable Roof.
Fig. 164. Gambrel Roof.
The gambrel roof is a variation of the simple pitch or gable roof and was probably developed from it to meet a new condition, namely, the necessity for more space in the portion of the building immediately under the roof surface. This form of roof has a sort of gable at each end of the building, but the gable is not triangular in shape, as is shown in Fig. 164. It will be seen that the roof surface has been broken near the middle on both sides of the building and that the portion below the break has been made steeper, and the portion above the break flatter than would be the case in a simple roof surface for a building of the same size with a gable roof. This arrangement allows of considerably more space and much greater head room in the attic. The position of the break in the roof surface may be varied to suit the taste of the designer, and the slopes of both the upper and the lower parts of the roof may be arranged as desired. Gambrel roofs may be seen on many old houses built in the Colonial days, and they have lately come again into favor for the roofs of cottages and small suburban or country houses.
Fig. 165. Mansard Roof.
The mansard roof, called by the name of the architect who introduced it, is like the gable roof except that it slopes very steeply from each wall toward the center, instead of from two opposite walls only, and it has a nearly flat deck on top. This form of roof gives better rooms in the attic space than does either of the two forms already described. It was at one time very popular for large suburban and city houses, but it is now seldom employed. The mansard roof is shown in Fig. 165. It bears a close relation to the so-called hip roof.
Fig. 166. Hip Roof with Ridge.