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Gypsum Plaster Scratch Coat Volume Calculator

Calculate the plaster volume needed for a scratch (base) coat over lath.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Scratch coat plaster volume

79.25 gal

High confidence
Equivalent volume
0.39 yd³

Running these inputs gives 300 as the scratch coat plaster volume. Currently reading for United States under IRC 2024 — pick a different market above and the figures re-cast accordingly.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Three-coat plaster system volume per coat = wall area × coat thickness; the scratch coat is typically the thickest of the three coats (commonly ~10 mm)

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Frequently asked questions

Why is the scratch coat the thickest of the three coats?
The scratch coat has to fill the keys of the lath and establish a solid base for the coats that follow, which typically makes it the thickest layer in a three-coat plaster system, commonly around 10 mm.
How is plaster volume converted to liters?
Volume in cubic meters is multiplied by 1,000 to convert to liters (1 m³ = 1,000 L), since plaster and other wet mixes are commonly quoted and mixed by liter or gallon rather than cubic meter.
Does this account for lath keying or texture that increases material use?
No — this is a straight area × thickness volume calculation. Rough or heavily keyed lath, and any hand-applied texture beyond a flat coat thickness, will use more material than this base volume.