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Materials & Specificationsaka: drywallaka: sheetrockaka: wallboardaka: GWB

Gypsum Board

In Plain English

The gypsum panel product used to finish interior walls and ceilings.

Definition

Gypsum board is a panel product made of a gypsum plaster core faced with paper, used for interior walls, ceilings, and shaft walls. It is available in standard, moisture-resistant (green board, purple board), and fire-rated (Type X) varieties. Gypsum board is the dominant interior finish material in commercial and residential construction in North America.

Why It Matters in Bidding

Gypsum board is one of the highest-quantity interior finish items on most commercial bids, so small takeoff errors in board count, type, or layers multiply quickly across thousands of square feet. Estimators must price the correct variety (Type X fire-rated, moisture-resistant, abuse-resistant) because substituting the wrong product can fail fire-assembly ratings and trigger costly rework during inspection.

Example

The drywall subcontractor's bid separated standard half-inch board for offices from Type X five-eighths board in the rated corridor walls, since the fire-resistance rating drove a higher material and labor cost per square foot.

Related Terms

DrywallMetal StudFire-Rated AssemblyFire Resistance Rating

Frequently Asked Questions

They measure wall and ceiling areas from the drawings, separate them by board type and thickness, account for both sides of partitions and multiple layers on rated assemblies, then add a waste factor. Quantities are converted to standard sheet sizes for pricing and purchase orders, with fire and moisture ratings tracked per location.
There is no practical difference; drywall, sheetrock, wallboard, and GWB are all common names for gypsum board. Sheetrock is a brand name often used generically. Specifications and submittals typically use gypsum board, while field crews and many bid documents use drywall interchangeably for the same panel product.
Different varieties carry different material costs and installation requirements. Type X provides fire resistance for rated assemblies, moisture-resistant board suits wet areas, and abuse-resistant board adds durability. Pricing the wrong type understates cost and can void a tested fire or sound assembly, leading to failed inspections and rework liability for the subcontractor.

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