What is the highest R-value I can expect in the walls of a building, if I build the walls of concrete block?
R-values as high as 17 can be achieved using a lightweight 12x8x16 Hi-R insulated block wall with foil backed gypsum board on furring strips on the inside surface of the wall. If the wall is exposed block on both sides, an R-value of approximately 13.7 is attainable with a lightweight 12x8x16 Hi-R block wall.