What is the proper way to seal the ridge when working with clay tile?

What is the proper way to seal the ridge when working with clay tile?

• A. Cement mortar only
• B. Cement mortar or mastic
• C. Silicone sealant only
• D. None

Answer: (B)

Sealing the ridge on a clay tile roof must use a durable material that stays in place and accommodates the movement of tiles over time. Cement mortar is the traditional method, bedding the ridge cap and sealing between tiles to create a solid, weatherproof joint. In some systems, a compatible mastic (a flexible sealant) can be used as an alternative to mortar, providing a seal that can tolerate slight movement and thermal expansion without cracking. Silicones, while they resist water, don’t hold up well on clay tiles for ridge work because they don’t bond reliably to porous tile and can degrade with UV exposure and movement, leading to failures. Because ridge sealing needs to be watertight and compatible with clay tile, the proper approach is to use cement mortar or a suitable mastic as specified by the tile and underlayment manufacturers.

Sealing the ridge on a clay tile roof must use a durable material that stays in place and accommodates the movement of tiles over time. Cement mortar is the traditional method, bedding the ridge cap and sealing between tiles to create a solid, weatherproof joint. In some systems, a compatible mastic (a flexible sealant) can be used as an alternative to mortar, providing a seal that can tolerate slight movement and thermal expansion without cracking. Silicones, while they resist water, don’t hold up well on clay tiles for ridge work because they don’t bond reliably to porous tile and can degrade with UV exposure and movement, leading to failures. Because ridge sealing needs to be watertight and compatible with clay tile, the proper approach is to use cement mortar or a suitable mastic as specified by the tile and underlayment manufacturers.