An example exhaust duct assembly includes a front liner, an intermediate liner and a rear liner. Each of the front, intermediate and rear liners include an inner liner exposed to combustion gases and an outer liner spaced radially apart from the inner liner. An air passage defined between the inner liner and the outer liner provides cooling air utilized for insulating an inner surface of the exhaust duct assembly. A closeout member is provided between the inner and outer liner and defines a portion of an air passage between the closeout member and the inner liner. Air flowing through the air passage is injected into a joint to provide cooling. The closeout member includes a horizontal leg that is bendable in a radial direction to accommodate relative movement between the inner liner and the outer liner.