Plaster Thickness Tables

Table I Vertical Plaster Nominal Thickness
walls

	1	2	3	4	5	6
Vertical Substrage (walls) A	Method	Cement Plaster Basecoat			Stucco Finish Coat	Total Thickness A
		1st Coat (Scratch)	2nd Coat (Brown)	Total Basecoat
Sheathed Construction B	Basic Stucco System C	3/8"-1/2" 9-12 mm D	3/8" 9 mm D	3/4"-7/8" 19-22 mm D	1/8" 3 mm	1/2"-5/8" 12-16 mm J
Concrete Massonary Unity (CMU)
	Direct Applied (2-coat)		3/8"-1/2" 9-12 mm J	3/8"-1/2" 9-12 mm J	1/8" 3 mm	1/2"-5/8" 12-16 mm J
	Basic Stucco Systems C	3/8" 9 mm D	1/4"-3/8" 9-12 mm D	5/8"-3/4" 9-12 mm D	1/8" 3 mm	3/4" 19 mm E
Concrete
	Direct Applied Finish Coat G&H				1/16"-1/8" 2-3 mm G&H	1/16"-1/8" 2-3 mm G
	Direct Applied (2-coat) J		1/4" 6 mm H&J	1/4"-3/8" 6-9 mm H&J	1/8" 3 mm	3/8"-1/2" 9-12 mm J
	Basic Stucco System C	3/8" 9 mm D	1/4"-3/8" 6-9 mm D	5/8"-3/4" 16-19 D	1/8" 3 mm	3/4" 19 mm E

Table II Horizontal Plaster Nominal Thickness
soffits

	1	2	3	4	5	6
Horizontal Substrage (sofits) A	Method	Cement Plaster Basecoat			Stucco Finish Coat	Total Thickness A
		1st Coat (Scratch)	2nd Coat (Brown)	Total Basecoat
Framed / Shreaded Construction I	Basic Stucco System C	1/4"-3/8" 6-9 mm	1/4"-3/8" 6-9 mm	5/8"-3/4" 19-22 mm	1/8" 3 mm	3/4" 19 mm E
Concrete Massonary Unity (CMU)
	Direct Applied Finish Coat G&H				1/8" 3 mm G&H	1/8" 3 mm G
	Direct Applied (2-coat) J		1/8"-1/4" 3-6 mm H&J	1/8"-1/4" 6-9 mm H&J	1/8" 3 mm	3/8" 9 mm J
Concrete
	Basic Stucco System C	1/4"-3/8" 6-9 mm	1/4"-3/8" 6-9 mm	5/8"-3/4" 16-19 mm	1/8" 3 mm	3/4" 19 mm E
	Direct Applied (2-coat) J		1/4" 6 mm H&J	1/4"-3/8" 6-9 mm H&J	1/8" 3 mm	3/8"-1/2" 9-12 mm J
	Basic Stucco System C	3/8" 9 mm D	1/4"-3/8" 6-9 mm D	5/8"-3/4" 16-19 D	1/8" 3 mm	3/4" 19 mm E

Notes for Stucco Thickness Tables I &II:

A. The plaster thickness is measured from the face of the substrate. For soffits, the plaster thickness is measured from back of expanded metal lath (exclusive of rib).

B. Sheathed framed construction is recommended rather than open-frame construction. The thickness of the cement plaster for these two types of construction would be the same.

C. Basic stucco system refers to a stucco assembly with lath.

D. An accepted and recommended application of the basecoat is the double-back method, which is the process of successive coats with little or no delay.

E. Basic stucco system should have a minimum thickness of 3/4 inches (19 mm), which can include a 1/8-inch (3 mm) stucco finish coat.

F. If a fire-resistance assembly is required, the minimum thickness of cement plaster must be 7/8 inch (23 mm), which can include a 1/8-inch (3-mm) stucco finish coat. If the finish is an acrylic finish coat or some other approved coating, the basecoat of cement plaster must be a minimum thickness of 7/8 inch (23 mm).

Note: Plaster thickness should conform to the applicable building codes.

G. Stucco finish coat directly over concrete is also referred to as a skim coat.

H. It is recommended that a liquid bonding agent be applied to concrete before the application of a direct cement plaster basecoat or stucco finish coat.
I. The soffit framing construction options for the basic stucco system are:

1) direct to a joist system

2) suspended system

3) furring/sheathing system

J. Direct-applied cement plaster to a concrete or concrete masonry surface that exceeds the maximum thickness requires self-furring lath.