Can You Insulate Existing Walls. Fiberglass does have one weakness, however. Walls of older homes built before the 1970s and even as late as the 1980s often will not be insulated, unless foam injection insulation is like those individual cans of foam insulation you can buy at a home center but.
Then installers use special equipment to blow fiberglass.
Internal wall insulation usually involves fitting insulation boards or building a stud wall filled with insulation. External insulation is added by fitting insulation to the outside of the wall and covering it with render (shown below) or brick slips. Walls that have not been insulated can lose anywhere between 30% and 45% of the heat in your home. Solid walls can be insulated either internally or externally.