Do your sheets work on a mattress over 11" thick? April 06, 2022 19:29 Yes, our sheets are designed to fit mattresses with a thickness from 11" to 14". Related articles Is the mattress protector a full encasement? Will your mattresses develop body impressions? Can I use the handles sewn into the side panels of select mattresses to lift or transport the mattress? Can I adjust the firmness of the Premium Shredded Foam Pillow? Will the mattress protector reduce the breathability of the mattress?