The thermally insulated and airtight building envelope must be designed with as few gaps as possible. With regard to the position of the insulation layer, there are several options in old buildings, which must be evaluated differently with regard to thermal bridge effects.

• Course of the insulation layer in the area of the cold cellar
• Course of the insulation layer in the area of the upper building closure: top storey ceiling or roof
• Dealing with the heated staircase in the area of the cold cellar and the unheated roof space

For the position of the airtightness layer, see the separate airtightness checklist.

• at the perimeter in combination with the basement ceiling

• at verge and eaves,

• at the transition of the façade element ─ to the top storey ceiling. Only provide fire protection plates in the rear ventilation space of the outer skin. They must not pass through the insulation level.

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