Do Your Sheets Work on a Mattress Over 11" Thick? March 30, 2022 20:08 Updated Yes, our sheets are designed to fit mattresses with a thickness from 11" to 14". Related articles What If My Mattress Feels Too Firm? How High are Your Foundations/How Much Storage Space is Under the Foundation? How do I Choose the Correct Loft for My Pillow? Is the Mattress Protector a Full Encasement? Can I clean the cover of my mattress?