I live in a house where there used to be a latrine container connected to the toilet. The space where the container was is now used for rough storage. The lid for the space is a large (110x190 cm) sheet of metal (see image) that is cumbersome to lift. I would like to have easier access to the space and am thinking about how to construct a more convenient lid.
I would now like to have tips on constructions that would meet the two requirements I have: keep water out and not be so heavy that all adults in the family can open the lid.