Cork insulation; a complete illustrated textbook on cork insulation ...

INSULATION PROTECTION 477
plaster naturally breaking first in these grooves. Evidently a plastered
surface of this kind is but an imperfect moisture protection for in-
sulation.
Keep <strong>Cork</strong> Out of Wet Forms.—In concrete construction, which
method came into vogue at the same time, it was deemed good practice
and economy to place the ceiling cork right into the form, and
to pour the wet mixture on top of it, this being the recommendation
of the <strong>insulation</strong> contractor. It was hoped that the corkboard would
bond perfectly and securely with the concrete, and as corkboard had
been declared immune against moisture, no one suspected that the
insulating effect would diminish under this method. However, the
writer knows of many cases where such corkboard continues to
drop ofif the ceiling, consequently this method must be condemned
as very unsatisfactory. The rule that <strong>insulation</strong> should always be
kept out of contact with moisture must ever be borne in mind.
In ceiling work it is frequently possible to apply the <strong>insulation</strong>
above the ceiling, where there is no danger of its coming loose. The
work there is cheaper and better than at the underside of ceiling,
especially if girders and beams have to be covered.
The cement mortar construction has now been in use for about
twenty years, but since about 1920 its shortcomings have been recognized
by many users. Cement mortar in the thin layers used with
<strong>insulation</strong> is porous and not only imparts the initial quantity of
moisture to the corkboard, but it cracks readily and thereby permits
moisture from the air to enter day after day. Now that a far better
bonding material which is strictly waterproof is available, the use of
cement mortar is to be avoided whenever possible.
Asphalt for Damp-proofing.—The modern protection of all sorts of
insulating materials is an asphalt emulsion, equivalent to a pulverized
pure asphalt mixed with a certain amount of cold water, prepared
in accordance with a process first developed in Germany and covered
by a number of United States patents. Under this method the
asphalt is broken up into minute particles averaging 0.001 to 0.005-in
in the presence of an inert mineral colloid such as asbestos fibres.
At the factory the asphalt flows into a high speed emulsifying machine
whose propellers whip the stream of asphalt into the most
minute particles and at the same time combine it with the water and
the colloid. In this way the particles of asphalt are held in suspen-
sion until after the emulsion has been applied on the job, when the
water disappears by evaporation, leaving the mixture of asphalt and
asbestos fibres behind, in the form of a homogeneous coating. This
emulsion can be applied cold with a brush by hand or by means of a
spraying machine.
This emulsified asphalt is being marketed under various trade
names such as Korkseal; Krodeproof; Rex Flintkote—emulsion and
mortar; Stonewall Plastic; Par-Lock Bond; Vorco Waterproofing
<strong>Cork</strong> Mastic, etc. There must be differences among these as in the