What is the minimum thickness that shotcrete can be applied?

Question :
What is the minimum thickness that shotcrete can be applied?
We are currently using shotcrete on a restoration project and have a concern at the corner locations are returning to tight recessed steel framed windows. There is an exterior wood molding approximately 1 inch from the tight corner that needs to be preserved. Do you have any suggestions as to how we can address this? Do we need to provide caulking between the wood molding and the shotcrete?


Answer:
Thicknesses depend on the structure and surface (surface prep is the key to proper bonding of shotcrete) the shotcrete is being applied to. Depending on the application 1/4 flash coat to 1 inch thickness can be the minimum. As far as shotcrete up to the steel windows, you have to consider that cracking may occur off of each corner. This can be minimized by adding additional reinforcement at those locations. It is common to tool in a joint around the windows so that we could apply a caulk later. The caulking will assure a waterproof seal between the window and the concrete during temperature changes that may create some expansion and contraction. You do not have to depend on the trim work to create the weather and water tight seal the architect requires.