Abstract: A thermally insulated masonry wall comprising a plurality of thermally insulated barrier layers extending laterally inwardly from the surface of the wall. This is accomplished by placing a nozzle against the surface of the wall and blasting a pulsating air stream containing a thermal insulating liquid which penetrates through the surface of the wall to provide a first barrier layer embedded deeply in the wall and laterally spaced inwardly from its surface. A second operation provides a second but shallower barrier layer. This can be followed by a third or more applications. Each of the resulting barrier layers comprises particles of masonry material coated with thermal insulating liquid and entrapping air in the interstices formed by the coated masonry particles.