Tech Corner

Designed for architects, contractors, project managers or any curious mind who wants to peer behind the curtain into how a polyurethane passive house is built, the Tech Corner provides technical information about the materials applied in the Polyurethanes Passive House. The Tech Corner is also the place where you will find videos, photos and diagrams of the different steps of the construction process to help you understand what it takes for a house to meet the stringent passive house standard.

The Tech corner will be updated constantly as construction of the house advances, providing more and more detail about the materials and how to install them. Sign up for updates to keep up with the progress or send us your questions!

Ground floor

Overall, building the ground floor of the polyurethanes passive house is very similar to that of a traditional house. The main difference is the application of a polyurethane insulation board of 250mm (23 mW/mK) to cover the pipes on the concrete slab; polyurethane boards allow an even thickness of insulation, higher insulating performances and allows for the direct application of floor finishing.

The very low thermal conductivity of polyurethane boards and optimal airtightness allow minimum heat loss. Overall the expected U-value of the ground floor will be extremely low (0.1 W/m2K).

First and upper floors

Due to floor heating, each floor has to be insulated. On the first and second floor, polyurethane spray foam (27 mW/mK) will be applied between the concrete slab and floor finishing. As for the third floor, a special mortar made of 90% recycled polyurethane granulates will be applied below the polyurethane boards (23 mW/mK) to cover the pipes on the concrete slab.

External walls

The external walls are made from brick work blocks. The cavity between the external wall and the supporting wall will be filled with a layer of 180 mm thick polyurethane boards. In total the wall will be 450 mm thick, including a remaining 20-30 mm cavity between the polyurethane board and the external wall. This will allow for an external wall U-value of 0.10/0.11 W/m2K.

Separation walls between the two houses

To guarantee optimal acoustic separation between the polyurethane passive house tenants and their neighbours, the 40mm cavity between the two houses will be filled with open cell polyurethane boards.

Roof insulation

The Polyurethanes Passive House roof will be prefabricated to directly integrate polyurethane foam insulation into the roof structure. Blockfoam panels will be inserted between the rafters, integrating insulation directly into the roof structure allowing for better air tightness.

Flat roof

On the balcony above the room on the first floor, flat roof insulation is required to avoid heat loss. 240mm polyurethane boards (23 mW/mK) will be installed on top of the balcony slab.


Standard PVC windows will be used in the passive house, a sober white inside and warm wood imitation outside. The key here is quality glazing and polyurethane window frames for excellent insulation; this will allow tenants to avoid heat loss and make the most of the heating potential from sunlight.

Ventilation System