When installing thermal insulation boards on facades, dowels of appropriate length and density must always be used. The thickness of the thermal insulation board as well as the structure of the wall itself are also important. Always use plastic dowels. The length of the dowel itself must be the sum of the thickness of the thermal insulation board, the thickness of the applied layer of adhesive and a minimum of 3 cm entering the wall. When laying insulation on solid concrete surfaces, a dowel whose diameter of the nail is at least 1 mm larger than the diameter of the dowel (eg 10 mm for the dowel, 12 mm for the nail) must be used. If there is no such difference in diameters, there is a possibility that the dowel itself will not dissolve during driving. For insulation on walls with lower density, it is necessary to take into account the thickness of the insulation board and the adhesive and to use a suitable dowel.