My new twin 12 inch Memory foam mattress is arriving early and I’m not ready to put it on my bed for various reasons. I live in a very small space. Is it ok to unpack the mattress and lay it on its side while it expands? I know I’m not supposed to lie in it before 72 hours. Thanks for any advice!!
Hi carolyncaroline,
Welcome to the Mattress Forum! 
I would always confirm with your manufacturer first, but most boxed bed memory foam products have their layers laminated together, so storing the product on its side usually is not an issue for a few days. I would unroll it first in the “flat” position to make it a bit easier to manage and let it expand a bit there, and then transfer it to the side.
Phoenix