17. 8. 2023

Stud foil - its use and the most common mistakes during implementation.

Nop foil, a material that appears on almost every construction site. Unfortunately, you will find its incorrect use on every second building, which will harm the building rather than help it.

The film is used to create a drainage layer, as a separation, or a protective layer for underground structures.

Drainage layer

If you want to protect the building from pressurized water, you need to build a drainage system (drainage) around the building. The nop film will be used in this system as a drainage layer, which will safely lead the soil moisture flowing to the building into the drainage pipe, and through this pipe, the moisture will be safely carried away from the building.

The pictures show the nop film with the coated fabric during the implementation of the drainage

Mistake 1 – stud film in the drainage system is always laid with the studs pointing away from the structure. Geotextile should be applied to the nops (it can be purchased as a finished product), which will enhance its drainage function.

Mistake 2 – stud foil should never be applied alone, without a drainage pipe for water removal. If you use it this way, the water that reaches the foil will not pass into the wall of the building, but will be led down, where it can cause wetting of the foundation structures.

Mistake 3 – the use of stud foil towards the structure, which creates an air cavity for the removal of moisture from the masonry, sometimes there is also the idea that this can remove radon from the subsoil.In an air gap with a thickness of a few millimeters, there will not be sufficient flow to ensure the removal of moisture or radon.

Mistake 4 – the end of the nop foil is not finished above the ground with an end strip that would prevent moisture from entering behind the foil.

Mistake 5 – a frequent mistake when the stud foil is used to protect the ingress of moisture into the masonry separately without waterproofing.

The drainage system is only an additional protection of the building against moisture, which reduces the stress on the main waterproofing layer with pressurized water. Without a waterproofing layer, the building will never be sufficiently protected.

Protective layer

Nop foil can be used to protect waterproofing or thermal insulation instead of brick cladding. Here again the rule applies, the stud foil is always laid with the studs pointing away from the structure.

Figure: Using stud foil as a protective layer with studs facing away from the structure

Error - If the studs are turned towards the structure, the studs will "push" (press) into the waterproofing and the waterproofing will be irreversibly damaged.