The Healthy Sleep Premium Mattress Encasement - Queen Size would fit just fine. The encasement will acommodate mattress depths from 9 to 16 inches. The Healthy Sleep Premium Mattress Encasement is also designed to stop Bed Bugs from getting into the encasement or out of it.
Healthy Sleep Premium Mattress Encasements do have more stretch than some other brands of encasements so that each size can accommodate a wider range of mattress thicknesses. Even if there is some extra fabric, then the encasement will still work. You just may want to check any folds and treat them with insecticides since that it potentially a place where bed bugs could hide. You could also choose an encasement that is more tailored to the thickness of the mattress, such as Mattress Safe Sofcover Ultimate Encasement, which comes in two different thicknesses for each mattress size.
