Page 2 - 2017-04-CFR Volume 103 Gypsum Yes or No - April 2017

bound water also known as calcium sulfate dihy-
drate. This is important because dihydrate
means there are 2 molecules of chemically
bound and locked in water which makes it a fire
retardant or heat sink which is why it’s used in
multi-family. So if you do any multi-family work
the attributes of gypsum products are without
comparison. Natural gypsum sources for ex- The experts at LGM
ample that USG uses are very pure – well https://en.wikipedia.org/wiki/Gypsum specialize in consultation, correction
above 90% and some as high as 96%. Neither natural gypsum nor syn- and resolution for flooring complaints,
claims, installation and performance
thetic gypsum contain organics so they cannot support mold or mildew. issues.
This is another factor to consider when installing floating floors over No issue is too big, too small or too far
damp slabs that have to be prepared first. Gypsum is non-toxic and is away for us to handle.
neutral pH making it much less alkaline than PC or CAC-based con- All ads are interactive. Just click on
crete. the ad to enter their website.

Synthetic gypsum, more accurately
called FGD gypsum (flue gas de-
sulfurization) is a bi-product of the
cleaning of coal-fired power plant ex-
haust. Here’s how: Exhaust leaving the
combustion chamber of a coal-fired
power plant is first cleaned of ash. This
is done using filters. The collected ash
is called “fly ash.” The hot exhaust then
is forced through a limestone slurry.
The slurry is made up of finely ground
limestone and water. Limestone is
chemically called “calcium carbonate.”
As the exhaust passes through the https://en.wikipedia.org/wiki/Flue-as_desulfurization
limestone slurry, sulfur dioxide (which is a found in the exhaust) is then
“absorbed” into the limestone slurry. It is at this point when the lime-
stone slurry, aka calcium carbonate, converts into calcium sulfate –
gypsum! Synthetic gypsum is then calcined (cooked) just like natural
gypsum and as with natural gypsum USG can cook the gypsum in a
number of ways based upon the end use. Just like natural gypsum, syn-
thetic gypsum is free of organics which, like natural gypsum will not
support mold and mildew growth.
Gypsum strength is directly related to the
amount of water used during the rehydration
process as well as whether fillers such as sand
or gravel are used.

Page Layout By: Anita S. Drennon
2 Commercial Flooring Report April 2017