A solid load$-$bearing masonry wall is constructed of $4$ in face brick, $1$ inch air gap, $1$ in expanded polystyrene insulation board $($unfaced$),26$ framing $24"$ oc$,$ R$19$ batt insulation, and $\frac{5}{8}$ in gypsum wallboard.

a$.$ Determine the R$-$value and U$-$factor for this construction assembly under winter conditions.

b$.$ Determine the temperatures at the surfaces of each material in the construction assembly based on an outside air temperature of $19F$ and an inside air temperature of $72F($winter conditions$).$ Make sure to consider air film resistance.