The bed loft is more of a shelf. A double mattress fits up there but currently there is a slim single one. I used it as a spare sleeping space and went up there if I had an overnight guest below. The ladder is vertical - rather awkward if you want to get down to the toilet in the middle of the night after a few drinks! Really difficult if there are 2 of you up there and you're on the inside lane - not recommended! Other than the steepness of the ladder, the height is what's stopping it being a positive sleeping space. It's too low to sit up properly in bed.
Use it as a spare bed and a place to store suitcases and boxes.
