For ventilation in spaces that are typically located below ground level, ventilation is often provided through the facade or at ground level. In situations with heavy rainfall, splashing water, vegetation, or an increased risk of wind-driven rain, it may be desirable to position the ventilation outlet above ground level while the duct connection remains below ground level.
A ventilation shaft provides a reliable solution in such cases, as the air supply or exhaust outlet terminates well above ground level. This helps keep the opening free from contamination and significantly reduces the risk of water ingress.
A ventilation shaft is a vertical ventilation solution suitable for both air supply and air exhaust. The shaft is connected to a circular duct and terminates above ground level, allowing ventilation without the need for a direct facade opening above ground level.
Ventilation shafts are used for applications such as:
Because the outlet is positioned above ground level, ventilation is less affected by rainwater, snow, leaves, pests and splashing dirt.
Tilmar offers two ventilation shaft solutions: T177 Ross ventilation shaft and TilVent stainless steel ventilation shaft. Both systems can be connected to horizontal as well as vertical ducts.
The T177 Ross ventilation shaft is a widely used and visually attractive solution for ventilation below ground level. The shaft is suitable for both air supply and air exhaust and features a semi-circular design. This accessible and appealing shape provides an aesthetic addition in many situations. The plastic version (polypropylene) provides good protection against rainwater because the outlet is positioned well above ground level.
The T177 can be used in both new construction and renovation projects. In renovation projects, it can be connected to existing ducts or vents. The system has a modular design with vertical extensions of 450 mm, of which one extension piece is supplied as standard. Additional extensions are available separately and can be cut to size. The T177 must remain above the groundwater level and is not watertight against groundwater. For drainage of condensation and any penetrating moisture, good drainage is recommended, for example by installing a gravel bed underneath and around the shaft.
The TilVent stainless steel ventilation shaft shares many functional similarities with the Ross ventilation shaft. The TilVent is also suitable for ventilation above ground level, for both air supply and air exhaust, and features a modular design with protection against rainwater, contamination and pests.
The main differences lie in material, appearance and design flexibility. The TilVent is made from high-quality matte stainless steel (RVS 304) and is intended for applications where aesthetics are important in addition to functionality.
The TilVent consists of two components: a stackable shaft section of 500 mm and a protective cap providing excellent rainwater protection. Because the outlet is positioned well above ground level, effective ventilation is achieved with minimal risk of water ingress. The system is designed for both new construction and renovation applications and offers considerable flexibility in positioning and height.
Pest protection
When a ventilation shaft is installed in wooded or animal-rich environments, there is a risk of unwanted entry by mice, rats or birds. To prevent this, the TilVent is equipped with a stainless steel mesh module. This mesh is designed to prevent small animals from entering and is not intended as insect mesh.
For ventilation below ground level, it is important that condensation and any penetrating moisture can be drained away. This is preferably achieved through an opening at the bottom of an elbow section or by means of a T-piece installed in a gravel bed. The risk of penetrating moisture cannot be completely eliminated.
Both the T177 and TilVent ventilation shafts have a modular design. The T177 Ross ventilation shaft is available in Ø125 mm, Ø160 mm and Ø200 mm (internal). Choice of four standard colours: black, dark grey, light grey and beige. The length of the TilVent can be extended in increments of 500 mm, as the shafts are stackable. The TilVent stainless steel ventilation shaft is available in Ø125 mm, Ø160 mm, Ø200 mm and Ø300 mm (internal). As standard, it is supplied in matte stainless steel (RVS 304) or black, but other colours are available on request.
Airflow Capacity T177 Ross
T177-125 (Ø125 mm): net free area 123 cm², 5.5 dm³/s at 1 Pa
T177-160 (Ø160 mm): net free area 201 cm², 11.2 dm³/s at 1 Pa
T177-200 (Ø200 mm): net free area 314 cm², 20.5 dm³/s at 1 Pa
Airflow Capacity TilVent Stainless Steel
The airflow capacity varies by diameter and is specified as follows:
TilVent-125 (Ø125 mm): net free area 123 cm², 9.2 dm³/s at 1 Pa
TilVent-160 (Ø160 mm): net free area 201 cm², 15.1 dm³/s at 1 Pa
TilVent-200 (Ø200 mm): net free area 314 cm², 23.7 dm³/s at 1 Pa
TilVent-300 (Ø300 mm): net free area 707 cm², 53 dm³/s at 1 Pa
This range makes it possible to match the ventilation shaft to the required ventilation capacity.
A ventilation shaft is particularly suitable when:
When ventilation outlets must remain below ground level, a window well is usually the more suitable solution. More information can be found in the article about basement wells for crawl space ventilation.
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