Technical Booklet C Site Preparation and Resistance to Contaminants and Moisture·Page 31·6.11
Insulation placement in external solid walls
External solid walls must be insulated either on the inside (with a moisture-break cavity) or on the outside (with moisture resistance), to keep the wall relatively dry.
An external solid wall should be insulated on the inside or on the outside. Where the insulation is on the inside, a cavity should be provided to give a break in the path for moisture and, where the insulation is on the outside, it should provide some resistance to the ingress of moisture to ensure the wall remains relatively dry (see Diagram 6.4).
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