62 
House & Garden 
HOW TO BUILD A POOL 
A Practical Explanation of Methods to Follow in Performing What is 
Perhaps the Most Dificidt oj All Garden Feats 
S ometimes pools are called Na¬ 
ture’s jMirror, sometimes The Soul of 
the Garden. And there have been other 
names for them in garden writings, con¬ 
taining sentiment just as pretty. But it 
seems almost impossible to find any printed 
record of what they are called when they 
seep dismally away through an unexpected 
crevice, or when, on a winter’s night, they 
crack with frost. Unfortunately, there is 
no way to put a stop to those sweet banali¬ 
ties of the first instance, but there is a way 
to make the latter epithets unnecessary. That 
is by building pools which will neither 
crack nor leak. And that is easier said than 
done. But it can be done with a very ^air 
measure of luck if the methods outlined 
below are used. 
One hazard will lie in the fact that 
there is a temptation to undertake all gar¬ 
den affairs with your own hands. None but 
pool building should be resisted. Here you 
should stand firm, and turn the actual 
work over to skilled mechanics. Eor there 
is something about the crafts of plumbing 
and concrete-mixing which requires for a 
successful performance some previous sub¬ 
stantial experience. The situation of the 
pool, on the other hand, together with its 
size and appearance, should be determined 
by you or by your garden designer or ar¬ 
chitect. These matters will be touched up¬ 
on towards the end of the article. The im¬ 
mediate concern is practical. 
Generally speaking, an inside depth of 
2' is plenty for any but a swimming pool. 
It is plenty for the growing of almost any 
kind of water plant, and for the sort of 
RICHARD H. PRATT 
fish suitable for pools. Less depth is some¬ 
times preferable in pools which are to be 
lined with brightly colored tiles and filled 
with sparkling, transparent water and 
darted with flashing gold and scarlet fishes. 
The depth is mentioned first because it 
partly controls the depth of the excavation, 
which is the first important step in the 
operation. The other thing which controls 
the depth of the e.xcavation is the frost line. 
The distance below the surface of the 
ground reached by frost varies with the 
climate of the locality and the severity of 
the season. The frost line at your pool is 
not the depth to which frost goes in an 
average winter, but the greatest depth to 
which it has ever been known to go there, 
with 6" added to the distance for good mea¬ 
sure. This distance may be as great as S' in 
rigorous climates, while in the far south 
and on the lower Coast it seldom needs 
consideration. 
Regardless of the depth of the pool the 
outside walls must go below frost line. 
Otherwise there will be freezing under¬ 
neath and the consequent expansion wall 
more than likely crack the floor of the 
pool. Frost cannot get under to this vul¬ 
nerable spot if the side walls are sent down 
to the proper depth. I have made a draw¬ 
ing, shown below, of a section through a 
typical pool, which will illustrate this point 
as well as the others as they come up. Here 
the inside depth of the pool is 2', and the 
frost line is considered to be 3' 6" below 
the surface of the ground. If the outside 
depth of your pool comes below frost line, 
as it very often will, there is of course no 
need to carry the outside walls below the 
bottom of the floor. 
Another preliminary consideration, and 
a very important one, is that of setting the 
pool upon solid ground. Any settling of 
the earth upon which the pool rests is 
bound to result in a strain on the structure 
which it may or may not be able to with¬ 
stand. If it should resist the strain on its 
walls and floor it might shift bodily off 
a true level and the water line would 
lie on a disturbing angle w’ith the coping, 
while if it should give way it would open 
and drain off in a manner that was not 
part of the original scheme. Therefore, if 
the pool must be built on a fresh fill, let 
the side walls go down to solid ground and 
tamp the earth well before pouring the 
concrete of the floor. 
Frost, next to poor construction, being 
the chief enemy of pools, the more care 
taken to prevent damage in this direction 
the better. Thus the caution is suggested 
of filling in behind the side walls wdth a 
6" layer of cinders and the laying at the 
bottom of this cinder fill, below the side 
walls, of sections of open tile drain pipe 
which will carry off the water that seeps 
easily through the cinders. Without this 
cinder backing, water is apt to collect 
against the walls, and, freezing, perform 
its devastating stunt. 
In setting the forms for the sidewalls 
another bit of safety may be practised by 
giving both faces a slant (technically 
knowm as a “batter”) of an inch or so, 
from the bottom to the top, towards the 
{Continued on page 100) 
A cross section through a typical garden pool oj concrete, showing the methods of construction which may be used 
and the principles of design which may be applied on pools of almost any size or shape. 
