In HVHZ, re-cover applications shall not take place over which existing material?

In HVHZ, re-cover applications shall not take place over which existing material?

• A. Asphalt shingles
• B. Wood shingles
• C. Clay tiles
• D. Metal shingles

Answer: (B)

In HVHZ, the surface underneath a new roof must provide a solid, stable base that can properly hold the fasteners and resist wind uplift. Wood shingles are not a suitable substrate for a re-cover because they can be warped, cupped, or rotten, and their nails may have been driven at angles that don’t align well with a new layer. Overlaying a new roof over wood shingles can trap moisture, hide damage, and create an uneven, less secure surface, all of which undermine the wind-resistant performance required in high-wind zones. For that reason, re-covering over wood shingles is not allowed; the old layer typically needs to be removed to expose a solid deck before applying the new roofing system. Asphalt shingles, clay tiles, and metal shingles can generally be re-covered over under HVHZ rules if the underlying conditions are sound and the installation meets wind-resistance requirements, which is why wood shingles stand out as the disallowed option.

In HVHZ, the surface underneath a new roof must provide a solid, stable base that can properly hold the fasteners and resist wind uplift. Wood shingles are not a suitable substrate for a re-cover because they can be warped, cupped, or rotten, and their nails may have been driven at angles that don’t align well with a new layer. Overlaying a new roof over wood shingles can trap moisture, hide damage, and create an uneven, less secure surface, all of which undermine the wind-resistant performance required in high-wind zones. For that reason, re-covering over wood shingles is not allowed; the old layer typically needs to be removed to expose a solid deck before applying the new roofing system.

Asphalt shingles, clay tiles, and metal shingles can generally be re-covered over under HVHZ rules if the underlying conditions are sound and the installation meets wind-resistance requirements, which is why wood shingles stand out as the disallowed option.