Dormers are of two kinds - those built entirely on the roof, as in Figs. 163-166, and those which form a continuation of the wall, as in Fig. 162.

On isolated or suburban residences the former are more common, although on story-and-a-half houses the latter are often used. Dormers of the latter kind are very common on the fronts of public buildings and city residences, but they are usually built either of masonry or metal, and often with elaborate gables, pilasters, etc.

Fig. .

There are so many different styles of dormers, and so many different ways of roofing and finishing them, that it is impossible to much more than allude to them. As a rule, the eaves and roof are made to correspond with those of the building, except that where the eaves overhang the main roof there is no necessity for a gutter.

To be of practical utility the window sill should be not more than . 2 feet, nor the top of the window less than 5 feet, above the floor.

A few examples of common types of dormers are shown in Figs. 161-166. The simplest method of roofing a dormer, when the main roof rises high enough, is that shown in Fig. 162. The roof of the dormer should have a pitch of at least 30°, and the outer edge should be provided with a gutter and conductor.

For dormers placed on the roof a gable or hip roof has generally the best appearance, and for these the style of finish shown in Fig. 163 is about the cheapest. On houses of the colonial type dormers similar to that shown in Fig. 164, or with a semicircular roof and gable, are often used, and frequently a single dormer of this type is placed between two of the type shown in Fig. 163. When the gable end is semicircular the roof is generally of the same shape and covered with tin or copper, but when the gable is finished as in Fig 164, a pitch roof covered with slate or shingles is often used, the gable cornice being made about 10 or 12 inches wide on top and covered with tin or copper, as shown at T, and the roof dropped behind it, as with masonry walls.

Fig.163.

Fig. 164.

Figs. 165 and 166 show types of dormers often used on shingled houses. These admit of a great variety of treatment.

Fig. 165 illustrates a style of shingled valleys that has become quite common on this style of building. The valleys, instead of being formed as described in Section 133, are rounded so that the courses of shingles may be made continuous from the main roof to the dormer. The juncture of the sides of the dormer with the main roof are also sometimes shingled in a similar manner.

The framing of the sides and roof of all of these dormers is very much the same, the description given in Section 82 applying to nearly all wooden dormers.