In the next episode when *Alternative* SHIELD finds out where Skye is they say

> The one that Banner built?

This cabin was constructed by Bruce Banner, and it is assumed that as the Hulk he is the one who punched the dent in the wall. This makes sense particularly when you consider how large the dent is. It is much larger than a normal sized fist, which is what Captain America has.

After Banner abandoned it, the cabin apparently became a safe house for people with powers who may not have total control over themselves yet or were initially feared by SHIELD.