The materials used for this concrete work have much to do with its
success. Ordinarily there is no need of inspecting the cement, for
most of the well-known brands of cement on the market are about as
reliable as human effort can make them. The materials which do need
consideration, however, are sand and gravel. The one essential of sand
is that it be free from loam, mica, clay, and organic matter. No sand
should contain more than 3 per cent by weight of loam or clay or 1 per
cent of mica. The quantity of loam or other fine impurities can be
determined by shaking the sand up with water in a bottle, and allowing
it to settle. The fine impurities will settle on the top and its
proportional relation to the sand estimated. To determine whether the
sand has much organic matter in it, a 12-ounce prescription bottle can
be filled with sand to 4½ inches and then added to this should be added
a 3-per-cent solution of caustic soda until this solution and the sand
fill seven ounces. The contents should be shaken well and allowed to
stand for twenty-four hours. If the liquid which settles on top shows
a dark color, then the sand has too much organic matter in it, but if
it is clear or slightly yellow it may be used without washing. The
size of sand particles should be such that they will pass through a
quarter-inch screen.
The usual size of aggregates should range from one-quarter inch to an
inch and a half in diameter, and the various sizes should be so graded
that they will make the most compact mass. The common run of bank
gravel must be screened and washed. To make really good concrete that
is water-tight, the grading of the aggregate is most important.
In fact, to determine the various quantities that should be used of
the materials on hand, some method must be adopted to give the quantity
of cement necessary to fill the voids in the sand and the quantity of
cement and sand necessary to fill the voids in the aggregate. A rather
crude way of doing this is to employ water as the measure of the voids.
Fill a pail with sand, and then pour water into it until the water,
which is absorbed by the sand, comes to the same level as the sand.
Note the quantity of water used up. If it represented 45 per cent of
the volume of the sand, then it is known roughly that about 50 per cent
of the volume of the sand ought to be the quantity of cement needed to
fill in the voids of the sand. Thus, one part of cement to two parts
of sand. If now the gravel is measured in the same way and it is found
that the voids show about 40 per cent of the volume of the aggregate,
then, assuming a little more than the water shows, about 50 per cent
of sand and cement will be required to fill up these voids. That is,
there should be just twice as much stone as there is cement and sand.
We finally, then, arrive at the proportion for the concrete as follows:
1 part of cement to 2 parts of sand to 4 parts of gravel.
The amount of water which is added to make the mixture of concrete
should not be too much. It should be of such a quantity that the mix is
mushy but not watery, even when it is to be poured into forms.
_Sidewalks and Porch Floors_
[Illustration: Concrete Sidewalk]
It is generally recognized that one-course concrete sidewalks are the
most successful when built by the average workman, for the slab is
of one uniform body and not two layers, which might not have knitted
together properly. For porch floors and walks these slabs should be
5 inches thick and laid on a good foundation. It is best to excavate
4 inches for the depth of the walk, tamp the ground, and pour water
over it, to note whether it is absorbed or stays on top. If it is not
readily drained off, it ought not to be used as the foundation of the
walk, but should be excavated to a depth of 10 inches to 12 inches.
In this excavation should then be tamped gravel or cinders, and some
provision should be made by which any water that would seep through
this gravel may be drained off. The timbers used for the forms along
the edges of the walk may be 2 by 6’s, held in position with pegs.
Slabs should then be determined for length. Usually they should not be
in excess of 6 feet in any one direction and ¼-inch expansion joints
should be placed in the walks every 25 feet. If alternate slabs are
laid, the forms can be removed, so that the intermediate slabs can
be poured between them. Of course, a partial bond will be developed
between slabs in this way, but these joints will be the weakest point
in the walk, and if settlement takes place unequally and one slab
breaks from the other, the crack will develop at this joint and not
appear on the face. The expansion joints should, however, be real
separations, made with strips of asphaltic felt set between slabs. The
usual mixture for concrete walks should be 1 part cement to 2 parts
sand to 3 parts of gravel. The mixture should not have too much water
in it, and when poured into the forms the top should be levelled off
with a straight stick stretched across from one side of the form to
the other. Too much trowelling should be avoided, since this is apt to
draw excess water to the surface and also cement, which will show hair
cracks when hardened. It is best not to use a metal trowel but a wooden
one, so that a partial sandy surface is made. After the walk has been
laid it should be protected from drying out too quickly by laying over
it 4 inches of earth or two or three layers of burlap, which should
be wet down about twice a day for a week. All walks and porch floors
should have graded tops, so that water will run off of them. This is
usually ¼ inch to the foot.
Sometimes porch floors give trouble from “dusting” and wearing away of
the surface to a gritty and rough condition. This may have been caused
by allowing the floor to dry too quickly or by having trowelled it
too much and drawn cement to the surface. It may be remedied by using
some one of the commercial floor hardeners or by painting the floor
with water-glass solution or boiled linseed-oil. Water-glass solution
should be diluted with 4 to 6 parts of water and applied with a brush
in as many coats as the concrete will absorb. When boiled linseed-oil
is used, it should be allowed to dry between coats, and as many coats
should be added as the concrete will absorb. Both of these treatments
will darken the floor, but the latter will darken it the most, and
appears to be more effective.
_Tennis-Court_
In laying out any other platform construction of concrete, such as a
tennis-court, the same principles of construction should be observed
which were given above for sidewalks. However, more care should be
taken with the drainage and foundation of the tennis-court. Not only
should the 6-inch cinder or gravel bed be laid, but all around the
outer edge of the court should be dug a trench about 18 inches wide and
3 feet deep. There should be laid at the bottom of this a drain-pipe,
with open joints, sloping from the centre of one end of the court
around both sides and joining together again at the middle of the other
end and connected with another pipe to carry off the water of that
drain-pipe to some lower level. The diameter of the drain-pipe should
be about 5 inches and the slope 6 inches from its highest level to its
lowest level. The upper surface of the court itself should slope across
from one long side to the other with a pitch of 2 inches. The division
lines of the slabs should follow as closely as possible the division
lines of the tennis-court. The length of the concrete platform should
be 21 feet greater at each end than the length of the court and the
width 12 feet wider each side. This makes the entire concrete court 60
feet by 120 feet.
[Illustration: Concrete Tennis-Court]
_Concrete Driveway_
[Illustration: Concrete Runways to Garage]
Such driveways may lead to the garage or up to the porch of the house.
One of the cheapest types to the garage is a double runway for the
wheels of the automobile. These runways should be about 4 feet 8 inches
on centres and made 18 inches wide. They should be constructed in the
same way that walks are built.
Where a full-width concrete driveway is built, it should be made about
6 inches thick at the centre and 5 inches at the edges, sloping from
the centre out. At intervals of every 25 feet expansion joints should
be built as was specified for walks.
_Concrete Steps_
The only difficult problem in the construction of concrete steps is the
making of forms. These should be well braced to prevent bulging when
the concrete is tamped into them. The aggregate ought not to be over ¾
inch diameter, so that as the material is tamped into the forms and the
sides spaded, a good surface will be left when the forms are removed.
If the aggregate is too large, some pieces may catch along the forms,
and when they are removed large holes will be found in the risers of
the steps. The treads should be finished with a wood trowel.
[Illustration: Concrete Garden Retaining Wall]
_Small Retaining Walls_
Wherever terraces or lawns need the support of a small retaining wall,
concrete is excellent for this purpose. The foundations of such walls
should be carried down below the frost-line. The usual mixture is
1 : 2 : 4. Drains should be built at intervals along the lower part of
the wall, to allow the seeping ground water to come out. At intervals
of about every 25 feet expansion joints should be made, somewhat
the shape of the tongue and groove in flooring. The base of such a
retaining wall should be at least as wide as ⁴/₁₀ the height of wall.
_Pools and Fountain-Basins_
[Illustration: Concrete Pool]
Such ornaments to the garden are not entirely outside of the
possibilities of the small house owner’s pocketbook. They should have
the exterior walls carried down below frost-level, and the bottom and
sides reinforced with steel. For the bottom woven-wire reinforcement
will answer the purpose and for the sides ⅜-inch reinforcing rods
should be used. These pools ought not to be more than about 2 feet
deep, in which case the bottoms may be made 6 inches thick and the
sides 12 inches at the top and 14 inches at the bottom.
_Ornamental Garden Furniture of Concrete_
[Illustration: Simple Types of Concrete Garden Seats]
There is no great difficulty or secret in making simple garden
furniture of concrete. Generally where the furniture is of simple
lines, the mould can be made of wood. If, say, a bench is to be made,
the top might be moulded as a slab of concrete, and the legs at the
ends as slabs, and all fitted together. If flower-boxes are desired,
the mould would necessarily have to be a little more complicated,
but not greatly so. The one thing to remember in making any of these
moulded bits of concrete is that they should always have embedded
inside of them reinforcing wire lath.
[Illustration: Concrete Vase for Garden]
Of course the making of ornamental pots and vases is rather difficult
and takes some skill. Here the original shape must be modelled in
clay, and a plaster mould made of it, which is shellacked inside and
greased. Special cores must also be designed, and where fine surfaces
are desired various processes of mixing ingredients must be resorted
to. This is a special field of itself, and men who do this kind of work
generally have studied out methods of their own. Some examples of this
kind of work are illustrated.
XVIII CLASSIFICATION AND CONSTRUCTION OF THE ARCHITECTURAL MOTIFS USED
IN SMALL-HOUSE DESIGNING
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.
[Illustration:
Square Plan
Rectangular Plan
“L”-Plan]
[Illustration:
Rectangular Plan with Small Extension
T-Plan]
[Illustration:
Combination of “T”-plan with L-plan
U-Plan]
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.
[Illustration: GAMBREL GABLE]
[Illustration: WALL GABLE HIP ROOF FLAT ROOF]
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.
[Illustration:
A
B
These two houses are ugly as sin, yet are considered very practical.
All rooms on 2nd floor are square and cellars are high and dry.]
[Illustration: C
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.]
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.
[Illustration: VARIATIONS OF DESIGN DEVELOPED FROM THE FEW FUNDAMENTAL
STRUCTURAL MOTIFS]
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.
[Illustration: GAMBREL ROOF CONSTRUCTION]
[Illustration: CONSTRUCTION OF GABLE ROOF]
[Illustration: HIP ROOF CONSTRUCTION]
[Illustration]
[Illustration: CONSTRUCTION OF A DORMER]
Even when it comes to the design of dormer-windows, the limits
of originality are quite restricted. The drawings show all of the
possible types that have been used with any success. Variations in
the proportions and the details of these motifs is about all that the
designer can hope for, and yet this is one of the hardest problems to
solve. The correct designing of dormer-windows is a very rare thing to
be seen. How many houses of modern Colonial style have ugly dormers!
They are usually made too large and too wide and fat. The dormer-windows
used in the old Colonial houses were narrow and high, and in those
proportions were their charming appeals. To-day a double-hung window
with weight-boxes is used in these dormers, and the whole width made
too wide because of these additions to the sides. This is a warning
that the designer should be careful in adapting old motifs to modern
requirements. This particular problem has been correctly solved with
the use of the weight-box, but how many times it has not been solved
is evident on all sides. Another unfortunate use of the dormer-window
motif is the extension of the second floor up through the lower slope
of the gambrel roof. This cuts away any legitimate lower section of the
gambrel roof, and in order to preserve it, the designer projects it
outward from the ends of the house, and has it skirt by the side of the
second floor like an added toboggan-slide with no earthly reason for
its existence. Then, too, the prairie-schooner dormer, the semicircle
one, and the eyebrow dormer are certainly types to be used with great
care, for they can become eyesores without effort, and they cost a
good deal to construct. Where the dormer is to be made inconspicuous
the flat-roof type has been successfully employed, but the roofing
material on it should be tin or copper. In some of the trap-door types
of dormers where the pitch is very slight, the roofing material ought
to be of sheet metal. The sides of dormers are made less conspicuous by
covering them with the same material as used on the roof, but this is
not always desirable. However, all vertical joints of dormers with the
roof should be carefully flashed to prevent leaks.
[Illustration: FLAT TREATMENT OF GABLE END]
The treatment of the gable ends of dormers is practically the same as
that required for the treatment of the gable ends of the main roof.
Here again, although on the face of it there seem to be innumerable
ways of treating the gable ends of roofs, yet there are comparatively
few methods. The drawings show about all the possible ways, and any
types which appear to differ from these can be shown to be merely
variations. The simplest method of treatment is to place a small
moulding under the ends of the shingles. A variation of this can be
made by adding a wide board below the moulding or a course of shingles
running parallel with the edge. The classic cornice can be used, but
great taste is needed in handling this motif, for any pitch which is
not of the traditional classic pediment form is apt to look badly. The
verge-board motif comes from half-timber traditions, and is generally
used in a very careless fashion. In general, it usually looks best when
some visible means of support is made a part of the design.
[Illustration: FLAT TREATMENT OF GABLE END]
[Illustration: ADAPTATION OF CLASSIC PEDIMENT]
[Illustration: VERGE-BOARD TREATMENT OF GABLE END]
The shingle imitation of the thatched-roof gable is one of those
amusing architectural fads which do not have very deep roots, and
sooner or later are forgotten.
The wall-gable treatment is very dignified, but is usually associated
with larger houses, but when simplified it has a charm which none of
the other motifs can offer.
[Illustration: SHINGLE IMITATING GABLE END OF THATCHED-ROOF WALL GABLE]
Other than these few, there are no common motifs to use in adorning
the gable end of a roof. This and the previous statements only go to
prove that the originality of design in the small house is limited
within a narrow scope, and that the real beauty is not obtained in
trying to find different forms, but in trying to use the traditional
structural forms in the best proportions and giving careful attention
to the details. In fact, it has been said that house designing is
largely an assembling, into pleasing general proportions, of carefully
designed traditional details.