Thermal Insulation and Energy Efficiency

In accordance with EPBD, GEG and DIN 4108, external walls must achieve the required U-value (typically 0.20-0.28 W/m2K for new buildings under GEG, depending on climate zone). Insulation products must comply with EN 13162-EN 13171. Continuous insulation must minimise thermal bridges per EN ISO 10211 and DIN 4108 Supplement 2 (Thermal bridge catalogue).

1. Verify insulation material and thickness against energy calculation

2. Check continuity of insulation — no gaps at junctions, corners or around openings

3. Inspect for thermal bridges at structural elements (columns, beams, balconies)

4. Verify correct fixing of insulation (mechanical fixings, adhesive or both)

5. Use thermal imaging to detect missing insulation or thermal bridges

- Insulation gaps at wall-floor junctions creating thermal bridges

- Balcony connections without thermal break elements (Isokorb or similar)

- Insulation compressed or displaced during installation

- Incorrect insulation type for the application (moisture sensitivity)

In accordance with EPBD, GEG and DIN 4108, roofs typically require U-values of 0.14-0.20 W/m2K and ground floors 0.25-0.30 W/m2K (depending on climate zone and national regulations). Vapour barriers must be placed on the warm side of the insulation per EN ISO 13788 and DIN 4108-3 to prevent interstitial condensation.

1. Verify roof insulation thickness and material against design

2. Check vapour barrier for correct position (warm side) and continuity

3. Inspect insulation at eaves, verges and around roof penetrations

4. Check floor insulation for correct position (above or below slab)

5. Check for thermal bridges at wall-roof and wall-floor junctions

- Missing or insufficient insulation at eaves and roof edges

- Vapour barrier punctured by services or fixings

- Floor insulation crushed by heavy loads before concreting

- Thermal bridge at parapet or wall plate

In accordance with EPBD, GEG, EN 13829 and DIN 4108-7, building airtightness must be verified by blower door test. Typical requirement: air change rate <=3.0 h-1 at 50 Pa (n50) for new buildings with mechanical ventilation, <=1.5 h-1 for new buildings without mechanical ventilation per GEG, <=0.6 h-1 for passive houses. Controlled ventilation must be provided per DIN 1946-6 and EN 15251 to ensure indoor air quality while maintaining energy efficiency.

1. Check continuity of the airtightness layer (membrane/film) around the building envelope

2. Inspect sealing at all penetrations (pipes, cables, ducts) through the airtight layer

3. Inspect sealing at window and door frames

4. Perform blower door test per EN 13829 — result must meet the n50 target value

5. Check mechanical ventilation with heat recovery (MVHR) for installation and commissioning

- Airtightness layer not continuous — gaps at junctions and penetrations

- Window and door frames not properly sealed to the airtight layer

- Blower door test fails due to unsealed penetrations

- MVHR not balanced or filters not accessible for maintenance