There are not many architectural motifs that can be used in designing the small house, and the ones which are employed over and over again are fundamentally a part of the construction. The plan must build up into block forms, because of the requirements of construction, and the designer has only a handful of shapes that make good roofs, for the same reason. The varieties of dormer-windows that he can put on the roof are limited to a few that are capable of being reasonably constructed. He cannot be original in the forms he selects, for they have all been thought out before. He should know them as he does the alphabet and build with them as he builds words with letters.
For example, take the plan of the small house. Can there be much room for originality here? Usually there are at the most four rooms which must be arranged on the ground floor of the small house: the living-room, dining-room, kitchen, and pantry. On the second floor are generally placed the bedrooms. Does it not seem reasonable to assume that all of the best combinations of so few rooms must be quite limited in number, and that the chances are that they have already been thought out? Many a young designer has labored enthusiastically upon what he believes is his original layout for a small house, only to find later that his solution has been already worked out and perhaps a trifle better. When an inventor tackles any particular problem, his first step, if he is wise, is to consult the patents which have previously been issued along this line, and then he will know what has been done.
Try as hard as he will, no designer can get away from the fact that the cheapest arrangement of rooms in his small-house plan makes a square unit and builds a square block-house, but that such a plan is one of the most difficult forms to make pleasing to the eye. For this reason the room arrangement, which gives a rectangular-shaped house, is more often adopted. But we often tire of too much repetition of the rectangular house, and designers try to vary it a little. There is not much leeway here, however. By adding a wing at right angles to the main rectangle of the house, we can have an L-shaped plan which is easier to give architectural variety to, but very uneconomical, for the number of linear feet of exterior wall for a house of this shape is just as great as that for a house which is a rectangle in plan, as long as the L and as wide. This also holds true of the U-shaped plan and the T-shaped plan and the combination of the T and the L shaped plans. In fact, as soon as the designer tries to get away from the simplest rectangular shapes in the small house, the economic reins pull him back, and he must go slow in selecting too picturesque plans. Limited, therefore, in his possible scope, the real work of the designer should be one of perfecting the acceptable solutions which have been already worked out. Only once in a generation are absolutely new arrangements stumbled on.
On top of these various-shaped blocks, which these plans will form, a roof must be erected. Here again one would think that the architectural motifs would be quite varied, and yet when the matter is studied it is not the case. There are only five fundamental shapes of roofs which can be placed upon these blocks, and two of these types are really the same, and another ought not to be employed, so that, after all, there are actually only three fundamental roof motifs to use. These are the gable roof, the gambrel roof, and the hip roof. The wall-gable roof is merely a type of end treatment for the gable roof, and the flat roof is not suited to the average small house in the country or suburbs, because of traditions.
In the small house the designer has the choice of either placing these roofs above the second floor or placing the second floor within the roof. Where the former is selected he sets for himself a very difficult architectural problem - that of trying to make the proportions of a house limited in ground area fit under a roof placed too high. This has rarely been solved with any satisfaction, for in nearly all cases the house looks too high and stilted. The comparative drawings show how true this is. Notice how house A and B look stilted, while house C has a charm which no manner of designing would ever add to the former. Is it not a fact to be reckoned with that the small house is best solved architecturally if the second floor is placed within the roof? Economy of material is certainly secured in this way, and the construction is greatly simplified. The chief difficulties are to properly ventilate these rooms under the roof, and to give them good lighting without making too many and too large dormers. This is a hard problem, but it has been solved successfully. The Dutch gambrel roof was developed for this purpose, and there has been no doubt as to its beauty, except when wrongly used by placing it above the second story or poking the second floor through it in one long, single dormer.
This house is considered impractical, because rooms on 2nd floor are not square and are lighted with dormers, and the cellar is low and partly omitted, but architecturally something can be said of it.
It is quite evident from the above how important the roof designing is in the small house. It goes without saying that the simplest arrangement of roofs is the cheapest to build and the easiest to maintain. Every valley means a leak at some later date, for as careful as may be the builder, the history of roof valleys shows that they leak sooner or later. The designer cannot freely mix his roofs either. Gambrel roofs, hip roofs, and gabled roofs do not go together harmoniously, without considerable study, and as a general rule they should not be required to do so. The usual methods of construction of these types of roofs are indicated well enough in the drawings and need no explanation. The ridge-poles in all cases are not of any structural importance, but act as alignments for rafters. For this reason they are made only an inch thick. Hip rafters have much the same function in hip roofs. Whenever valley rafters are needed, these must be designed like floor girders. If dormers are built into the roof, it is customary to double the rafters around the openings. Where gable dormers are constructed, one of the valley rafters must be extended to the ridge-pole, or else the rafters will collapse.