We're installing a new shower in So Cal. The shower will include an existing window, but the window/wall will be closed part way up taking it from 43" x 43" to 43" x 18"H. So Builder is using mesh wire and concrete for walls both inside and outside before thin set and stucco is applied. Today we noticed a lot of cracking in the concrete both inside and outside; should we be concerned about this i.e. future leaking etc.?