Now, both of these types had advantages and disadvantages which were
bound to influence later builders. Those who had been accustomed to
build according to the braced-frame system found that lumber was
becoming scarcer, and that nails were cheaper than they formerly were.
Certain features of the balloon-frame appealed to them, such as its
greater speed of construction, its smaller timbers, and lightness.
On the other hand, those people who had lived in houses constructed
according to the balloon system of framing found that they were very
flimsy, that fires quickly consumed them, that rats and vermin could
travel freely through the walls, and that, after all, they were only
the most temporary sort of shelter. These folks looked back at the
old methods of building, and saw the good features of solidity and
permanence. We had, therefore, the growing together of the two systems
of construction into a type which we call the combination-frame
dwelling.
[Illustration: BALLOON-FRAME COMBINATION-FRAME]
However, progress did not stop at this point. The houses built
according to this newly devised system were found to settle unevenly,
which cracked plaster ceilings and walls and made doors and windows
into leaning parallelograms. The cause of this was found to be due to
the natural shrinkage of wood as it dried out. Now, all wood shrinks
mostly across the grain, and not with it, so that the amount of
settlement of any wooden wall depends upon the amount of cross-section
of wood which it contains. If there is more in the interior partitions
than in the exterior, it is certain that the floor-joists will settle
down on the inside ends more than the outside. This is exactly what
happened. It occurred not only in the combination-frame but in the
braced and balloon frame. Various devices were introduced to avoid this
defect, but all were more or less incomplete. Nevertheless, it all
led gradually to the development of the fourth type of construction,
which is called the platform-frame, for lack of a better name. This
frame solves the problem of uneven settlement in the wooden structure.
It also makes the location of the windows of the second floor
independent of those of the first floor, which is not the case with the
balloon-frame, for in this type the studs extend in one piece from the
sill to the plate, requiring the centring of the windows of the second
floor over those on the first.
The methods which are used in constructing the small house of to-day
are not as simply classified as the previous description would lead one
to believe. The old New England braced-frame has practically gone out
of existence, yet many of its features remain. The balloon-frame is
used only in the cheapest sort of structures, yet many of its details
are found in the modern dwelling; The combination-frame in all its many
varied forms can be called the advanced type.
_Study of Detail in the Combination-Frame_
The illustrations show the four types in their entirety. But in order
to fully understand the combination-frame, it is necessary to know what
features of the braced-frame and balloon-frame are used to-day.