Quantum gravity theories predict deformations of black hole solutions relative to their classical counterparts. A model-independent approach was recently advocated that uses metric deformations parametrised in terms of physical quantities, such as the proper distance. By assuming a minimal degree of regularity at the horizon, we provide explicit expansions of the metric function. This allows us to compute important thermodynamical quantities of the black hole, such as the Hawking temperature and entropy, for which we provide model-independent expressions. Moreover, imposing the absence of curvature singularities at the event horizon leads to non-trivial consistency conditions for the metric deformations themselves, which we find to be violated by some models in the literature.