Describe more than a color name
Historic clay roofs can include greens, blues, purples and other glazed colors as well as red or brown. Record whether the desired surface is glossy, muted, textured or intentionally varied. On an existing roof, compare protected and exposed examples before assuming every difference is a different original color. Preserve evidence of the finish before proposing an appearance change.
Develop custom colors through fired samples
Ludowici develops custom glazes by adjusting and firing formulas; texture can affect the appearance. Provide a physical reference and request fired trial samples in the intended texture. Agree on a range rather than expecting a digital paint number to define the result.
Review the range on full-size material
Ask to see more than a small color chip, including the finish on an edge or accessory where it will remain visible. For historic replacements, document how the proposed range relates to surviving tiles. GSA’s sample and mockup approach provides a useful discipline: identify the proposed material, demonstrate the appearance and retain an approved reference for subsequent comparisons.
Distinguish glaze markings from deeper damage
Fine cracks in a glaze and fractures through a ceramic body are different observations. NPS guidance for glazed architectural terra cotta distinguishes surface crazing from more serious material loss. That guidance is useful background, not a roof-tile diagnosis. Have the actual tile assessed before concluding that its surface pattern requires replacement or a coating.
Use a surface-specific care proposal
Do not select a cleaning method merely because the dirt appears stubborn. NPS warns that abrasive methods, metal brushes, strong acids and high-pressure cleaning can damage historic architectural glazes. Ask the tile manufacturer or preservation specialist for a compatible method and a small trial. Document the result after drying, including any change in sheen, color or surface texture.
Related questions
- Can changing a historic glazed roof from glossy to matte alter its character? →
- Can texture change the appearance of a glaze? →
- Can a paint number fully specify a custom glaze? →
- Is a fine network of glaze cracks the same as a broken tile body? →
- Why is abrasive cleaning a particular concern for historic glazed tile? →
- Should a varied historic clay-tile roof be painted to make its color uniform? →
Further reading & technical sources
- National Park Service · Preservation Brief 30 ↗
- Ludowici · Custom color development ↗
- GSA · Clay roof tile repair and reattachment ↗
- National Park Service · Preservation Brief 7 ↗
Consult the current product documentation and local requirements for your project. These introductions are not installation specifications.
Tile Roofing USA editorial guide · Published October 26, 2026.