My house is slump block construction. This is a kind of brick very common in Southwest. The interior is exposed slump block- no insulation. Can be very hot in summer and cold in winter. There is a company that drills holes in the mortar from the outside and sprays foam insulation under high pressure claiming it reaches all the cavities. They sat it increases the R value 5 times. Does anyone have first hand experience with this? Does it work?