Can these be used under thinset such as when installing bathroom tiles

Better to use the screws made specifically for the job. Your Lowe's associate can advise you.

Hello, we have not conducted testing regarding the use of Deck Plus screws in a bathroom, particularly under tiles. One concern is the high moisture levels in bathrooms, which may lead to rusting of the screws if they remain wet for extended periods. Additionally, the compatibility of the screws with the materials beneath the tiles is a crucial factor to consider. It is worth noting that thinset, commonly utilized for attaching tiles, is typically applied over concrete or cement, and it is important to highlight that Deck Plus screws are not suitable for use in concrete or cement. Thank you for your inquiry!