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A. In mineral form it is known as CaSo4 * 2H20
B. 100 Ibs. of gypsum contains approximately 21 Ibs. of water
C. Gypsum is mined and crushed
D. Then goes through a process called calcining where:

1. The gypsum rock is heated to approximately 350 degrees F driving off 3/4 of the chemically combined water.
2. The calcined gysum (CaSo4 * l/2H20 ) is ground into a fine powder used to produce gypsum plaster.
3. The calcined gypsum is then hydrated and fed between continuous layers of paper to form what is to be known as gypsum board.

E. Gypsum board is an excellent fire resistent material.
F. The core of the gypsum board contains chemically combined water which is released as steam under high temperatures which effectively retards heat transfer.
G. The sound isolation properties of gypsum effectively helps control sound transmission.

1. Nail field first nailing 7" o.c. for the ceiling and 8" o.c. for the walls.
2. To ensure straightness in walls, it is recommended that one works from the inside
3. To ensure straightness in walls, it is recommended that one works from the inside of the field toward the outside edges.
4. Be sure furring has straightened nailing surface
5. If double-nailing the first set of nails is 12" o.c. with the second nailing 2 to 2-1/2 inches from the first.
6. Second set of nails applied only to field not perimeter.

1. Maximum spacing for screws is 12" o.c. for ceilings.
2. Spacing for members spaced 16" o.c. is to be 16" o. c.
3. Maximum spacing for both walls and ceilings where the members are 24" o.c.

A. When taping mud is placed over the joint and then tape is placed over the mud.
B. The mud and tape is then flattened with a knife.
C. Once the mud and tape has dried, it is sanded and cleaned.
D. This process is continued until the mud and tape are flush with the drywall.

A. Square feet of finished floor space * 3.8 (or 4) is a fairly accurate estimate for the amount of drywall necessary to complete the job.
B. LF wall x Height of wall X no. Layers covered
C. 1/2" drywall is used for interior walls and ceilings.
D . 5/8" drywall is used as a fire barrier in the case of garages
E. Green board used in bathrooms. Used because of its water resistent properties.
F. 1 gallon of joint compound/150 sq. ft
G. 120 lineal ft. of tape/l50 sq. ft.
H 5-1/4 lbs. dry-tight nails/1000 sq. ft. 1-5/8"
I. 4 Ibs. grabber screws/1000 sq. ft. 1-1/4"
J. Corner bead to go on corners at ends of partitions
K. J-moulding used for:

1. Luminous paneling
2. Where you have exposed ends of sheet rock.

Nails:	Screws:
Ring shank	Type S (Used for Steel)
Cupped head	Type G (Solid gypsum)
	Type W (Used for wood)