---
title: "Type X drywall | Drywall Glossary"
url: https://tapeandfloat.com/glossary/type-x-drywall.html
language: en
author: James Grokman, CEO, TapeAndFloat
updated: 2026-10-28
---

# Type X drywall

**Type X is fire-resistant gypsum board defined in ASTM C1396, most often 5/8 inch and usually with glass fibers in the core, used where code or plans call for a fire-rated assembly, such as garages, corridors and shafts.**

## Why it matters on a drywall job

- Type X is usually heavier and costs more than regular board, so it belongs on its own line in the takeoff.
- A fire rating belongs to the whole tested assembly (for example, a UL design), not to the board alone. Rated walls can have specific fastening and taping requirements, so check the plans and local code.

## Related guides and tools

- [How to bid drywall](https://tapeandfloat.com/guides/how-to-bid-drywall.html)
- [Free drywall calculator](https://tapeandfloat.com/calculator.html)
- [All glossary terms](https://tapeandfloat.com/glossary/)

---

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