124 
T II E G A R D E X M A G A Z I X E 
1 
November, 191c 
> 
The walls of a greenhouse are that part of 
the foundation above grade that the super- 
structure rests on; in some cases the glass 
sides are carried to the grade line, but this is 
only to meet unusual conditions and generally 
speaking the walls are carried from two to 
three feet above the grade line. 
1 he old-fashioned wooden side is so out-of- 
date as to be hardly worth discussing — it 
is cheap, but needs constant repair. Where 
field stones are available, they are perhaps 
the cheapest of all masonry walls. Hollow 
tile plastered over is also very satisfactor}- 
because of the air space which prevents the 
wall frosting. Concrete blocks of good cjuality 
are a very good building medium, but un- 
fortunately these have got into bad repute 
because of the miserable product that is 
commonly sold as concrete block. Brick 
of all grades makes a good wall, and is .so 
common in permanent construction that it 
need not be commented upon. Cut stones 
of various kinds are often advisable where 
adjacent buildings of the same construction 
make it necessary. This point should never 
be lost sight of: Make your greenhouse walls 
of the same material as other nearby buikiings, 
whether residence or garage. Concrete is 
the most popular greenhouse wall and it can 
be had in a variety of finishes. It is being used 
so extensively in other work on country places, 
that its use for the greenhouse is very gen- 
eral. 
The inside walls and the inside of the 
foundation walls above 
grade should be made as 
smooth as possible so that 
they can be given a coat of 
cement wash occasionally. 
This makes a clean finish 
inside and should be done 
every second year. 
PITCH OF THE ROOF 
The pitch of the roof of 
a greenhouse has always 
been a bone of contention. 
4 he basic idea is to get the 
rays of sunlight as direct as 
possible during the winter 
months. Figuring the sun 
at an angle of 22 degrees, 
which is the minimum, we 
find 32 degrees the best 
average to meet the condi- 
tions during the hard grow- 
ing months of December, 
January, and February. 
1 hat is the concensus of 
expert opinion of green- 
house engineers to-day. 
Some houses are con- 
structed with only a five- 
inch pitch, however. 
1 here are, however, other 
important reasons for this 
pitch of roof. A pitch of 
32 degrees (which is 75 
inches to the foot), will keep 
the roof free from an ac- 
cumulation of snow and ice. 
It IS not so apt to be in- 
jured by hail because of the 
glancing blow; it also keeps 
clean from soot and dust 
which, in some soft coal 
districts and in most cities, 
is worth considering. But 
above all, it insures a tight 
roof. No matter how care- 
low pitched roof, driving rains are almost 
certain to find their way under the glass. 
TYFE AND STYLE OF FRAME 
A few years ago all greenhouses were con- 
structed with angle eaves, and the gutter at 
the eave line. Indeed with wood construc- 
tion one cannot very well get away from this 
type. W ith the advent of steel construction, 
the desire to give definition to the roof line 
led to the adoption of the curved roof or 
“curvilinear type” of house. Biit this type, 
while more pleasing to the eye, had many weak 
points. Glass of various sizes must needs be 
kept on hand for repairs, and it was found that 
glass laid on a curved line is more liable to 
become loosened than when imbedded on a 
perfectly straight line. Fhis and the desire to 
add more and better types to greenhouse con- 
struction led to the curved eave type of to-day. 
It was the steel house that gave us the curved 
eave, it being a matter of common sense to 
bend the construction at the eave line and use 
a light of curved glass rather than cut it and 
add a number of useless fittings. 
I he curved eave greenhouse has a perfectly 
straight roof and is architecturally superior to 
any other. It is a better growing house be- 
cause of the total absence of shading members 
at the eave line, the roof frees itself readily of 
ice, etc. 
Leanto. \Miere there is a suitable setting, 
such as the wall of a garage or other building, 
tne leanto greenhouse is the most economical 
to build, and although quite practical, yet' 
it is not in the same class as the even span 
house, so far as growing qualities are con- 
cerned. In the first place the light coming 
only from one side the plants have a tendency 
to “draw”; and ventilation is only available 
from one side. A leanto is an even span green- 
house cut in two lengthwise and its growino 
qualities are reduced accordingly. A south'^ 
erly or southeastern exposure is the only one 
worth considering for a leanto house. 
Three-Quarter Span. The style was more 
popular a few years ago than to-day. Where 
suitable conditions prevail, such as a steep 
grade, it is better adapted than any other, but 
for level conditions there is really no practical 
advantage. 
Even Span. Greenhouses are the best type 
for all general purposes. They look better, 
they can be given any desired exposure, and 
they are advocated by all greenhouse builders, 
which is a good proof of their value. .An 
even span house is one having the foundation 
walls the same height on both sides and the roof 
evenly pitched. The sides of the greenhouse 
can be made almost any height desired, but 
generally speaking for growing houses the 
spring line is three feet above the sill. This 
gives a height of three feet at the lowest 
point above the benches inside the house and 
of course the head room is increased rapidly 
by reason of the pitch of the roof. 
Other Forms. 
fully the glass is set on a 
The leanto, which is practically a half house, fits well on the side of a dwelling and can be made as a 
dwelling extension with ornamental features added 
I he roofs of greenhouses can 
be built in various ways, 
and differ somewhat, ac- 
cording to the uses of the 
house. Palm and show 
houses are constructed in 
octagonal, circular and vari- 
ous other pleasing forms; 
the roofs are hipped, dorm- 
ers or lanterns are added, 
and the construction 
changed in so many ways 
that are impossible of de- 
tailed consideration at this 
time. 
THE FRAME OF THE HOUSE 
The framing materials of 
which a greenhouse is con- 
structed depend entirely 
upon the amount of money 
one wishes to spend. .All- 
wood is, of course, the 
cheapest; semi-iron is next; 
and all-steel the most ex- 
pensive. The service or en- 
durance of each is in accord 
with the difference in cost. 
All-wood houses are very 
little considered to-day. 
\A ood will not last long in a 
greenhouse, the moisture 
laden heated atmosphere 
soon starts decay and repair 
bills quickly eat up the first 
savings. 
There are many reasons 
besides its wearing qualities 
to recommend the steel 
house. Having additional 
strength larger glass can be 
used, thus lessening the 
shading members appreci- 
ably; and as sunlight is the 
greatest asset in the forcing 
of plants, the logic of this is 
apparent. The houses are 
also better appearing; and 
