Book - School of Science and Technology

Atypical construction features 37Brick or concreteBrickThermal insulationPlasterboard on battensThermal insulationBrick or blockPlasterBrick or concreteAir gapThermal insulationPlasterboardBrickAir gapBrick or blockThermal insulationPlasterboardBrick or concreteAir gapThermal insulationAir gapPlasterboardBrickAir gapThermal insulationBrick or blockPlasterFigure 2.6 Methods of applying insulation to wallsFeatures to be noted in respect of filling wall cavities, in this and other ways, Figures 2.6and 2.7, are:. Cavities in the walls of new buildings may, of course, be filled in a variety of waysduring the construction period using materials such as expanded polystyrene sheet,glass or mineral fibre slabs and the like.. Cavities in the walls of existing buildings, where these are sound and not overly exposedto damp, may be filled by the injection of materials such as either urea formaldehydefoam or beads of mineral wool or polystyrene, treated with a water repellant, blowninto the cavity by air jet in a manner not dissimilar to that used with foam.. Insulation will reduce the initial cost of any heating system.. Cavity fill will reduce noise transmission from dwelling to dwelling as, for instance, atthe point of intersection with a party wall.. When a steady state condition is reached, the inner wall surface temperature will be at ahigher temperature than would be the case with an unfilled cavity, thus reducing therisk of condensation.. If heating is intermittent, the savings theoretically possible may not be achieved since allthe heat which has been absorbed in the inner skin during the `on' period may havebeen dissipated during the `off' period.