Working on the Loft Bedroom: Custom-fitting a Foam Mattress~

I've been working on the loft bedroom, and we're getting close to finishing it. All it needs now is to be styled! So there is a big reveal on the horizon, but today, I wanted to share with you all how I altered an existing foam mattress to fit the custom-sized "built-in" bed.





The mattress was previously used on the trundle bed in the boys' room.  And it is just foam (no wood or coils) which