slate porch floor–advice from the pros?
My next DIY project–
I want to lay a slate floor in an exterior but sheltered porch/entryway. New construction. Roughly 6×14 with two feet of the six cantilevered beyond the foundation. Overhead protection by porch ceiling and soffit but open to blowing rain and snow. Summer southern exposure to sun and 90-degree temps, winter to below zero (NW Wisconsin).
In place at the moment are 2.75″x9.5″ I-joists on 24″ centers. Plan is to scew down 5/8″ OSB subfloor topped with 1/2″ cement board as base for 3/8″ tile which will bring the final floor to level with interior floor and door threshhold.
So where are present and future problems? How do I seal the underside of the cantilevered sectiion? Add beef-up blocking between joists? Many thanks to those who know more than I do.