Lgk, Thank you for your question. We can only recommend installing this towel rack over an interior door. Best, Customer Care Team
krsms, Thank you for your question. This towel rack is 19.2 inches wide. Best, Customer Care Team
Door thickness up to 1.5". No, not suggested.
Sharon, Thank you for your question. If you click on the additional images on this page, there is a picture of the dimensions of this product. 31"h x 21"w x 11"d. Best, Customer Care Team
1.5 inch