Java slime survival, being able to go upper

[Jevmen]

Someone wasted his time making a detailed cellar with cobwebs, i want to access that zone, but there are barriers.
implement a way to go upper with stair and access the roof of the building please.
the roof can be a good hide spot and you can jump to any place from there as a scape route, but also is good for slimes because if you go up and unfortunely is empty at least you have a good view for seeking other survivors