How to add a thick coating to an interior CMU chimney
We have an interior chimney (center of house, surrounded by living space) that is CMU, previously clad with stone. The new vaulted ceiling will expose the upper portion of the chimney where it is corbelled out by a couple inches. We want to have flat surfaces from the floor to the new celing.
Can we build up 3 inches of stucco or similar product on the CMU? I see many posts where people are trying to go as thin as possible, but we need to go very thick to get a planar surface all the way up. Would prefer not to fir it out. Final finish will be American Clay
Replies
yes you can, it will more than likely cost you considerable more time and money to not fir it out but its doable.
if you are considering stucco, furring out and then layering plywood and mesh would gain a good 2-2.25'' and then your working with a much more manageable thickness.
can it all be stucco
Is stucco the right stuff if we want to do it this thick? We do not want to fir, at least not using wood, since there will be a wood burner immediately adjacent and we need non-combustibles.
Doug
Fur out with metal studs of proper width and secure the stud "wall" to the chimney with metal stand offs. Hang cement board up to wider existing chimney area flush. Embed mesh across that joint using Durabond, thin set or your stucco base coat. Finish as you see fit.
Use "expanded metal" mesh
Use "expanded metal" mesh lath under the stucco, and space it out from the masonry an appropriate distance with metal strips or simply washers on screws. A good stucco guy should know how to do this.