The Washington times., 1929-04-29
Slate Roofs Are
Durable, Colorful,
Weather Resisting
BY The Architects Small
House Service Bureau Of the
United States, Inc.

BY The Architects Small
House Service Bureau Of the
United States, Inc.
Metamorphism. That is a pom
derous word. 1t stands, though, for
important happenings. It indicates
change and in geology the word is
used to designate the transforma-
ton of one geological material into
another. Thus we have limestone
changed into marble and granite
into schist We have also clay
netamorphosed first into shale and
afterwards into slate.
BY the process of metamorphism,
through which the materials of
which slate is composed have gone,
a chrystaline material is built up
which has qualities of waterproof
ness, making it especially desirable
for roofs. The various minerals
that enter into the composition of
slate give it color.
We often define a certain tone Of
gray as SLATE color" yet colors of
slate range all the way from red to
purple, with shades of blue, green,
pink and yellow in between. Some
of the units are veined with diff
ferent colors and all are tempered
by the hand Of nature. They blend
into each other when used together.
Some of the units are mottled or
variegated, having two or more
colors No imitation can possibly
give just the quality which these
possess.
Texture, Color, Fire Resistance
In addition there is texture. The
original clay is decompoSed from
granite or other similar rocks and
is laid down in the beds of streams
where, after tens of thousands of
years, it is pressed and transformed
first into shale and afterward into
slate When this material Is quar-
ried il splits into layers or slabs,
but it does not break in geometri-
caIly excat places. There are rough
nesses and high and low points.
There are certain variations in
grain which come from the way the
units are broken out. These add
texture to the roof as no other ma
terial can.
When to these advantages is
added that Of high fire resistance,
slate becomes a valuable roof ma
terial indeed. In addition there
is a superior quality Of durability.
These stones last for generations.
They should always be accom-
panied in building by materials Of
equal weather resistance.
All of the metal work Of roofs
covered with. slate should be of
copper, which also has great dura-
bility. A heavy course of roofers'
felt laid directly under the slate is
a double assurance of waterproof
ness Condensation cannot cause
small, trying leaks.
English Roofs Of Stone
In England, where stone roofs
are most common, they are often
of a far more informal nature than
those to which we have become ac-
customed. The Englishman may
use heavy stones along the caves
and lighter ones at the ridge, grad
ing the thickness of the units and
and the exposures from caves to
ridge. Such a roof is called q
graduated roof. It is extremely
beautiful. They are used on many
of the finest homes in this country
Expensive-yes. But plain slate Is
not, when the whole cost, first and
last, is considered.
The covering to be used on roof
ought to be thought of as one hav-
ing qualities of permanence. 1t
should have durability at least as
great as that of the walls which
It protects. Slate is one of the
sound materials. It's durability is
unuuestioned. Texture and color
make it beautiful. 1t is metamor-
phosed clay-not such a ponderous
word after all. - Copyright 1929,
The Architects Small House Service
Bureau OF the. United States, Inc