Perma-Vent Condensation Control Vent 100mm (Telescopic)
A compact 100mm telescopic passive vent for walls from 300mm to 550mm thick. The adjustable duct fits without cutting, providing maintenance-free background ventilation to help reduce localised condensation.
100mm Telescopic Vent for Thicker Walls
The Perma-Vent Condensation Control Vent 100mm (Telescopic) provides passive background ventilation for walls between 300mm and 550mm thick. Its adjustable duct extends to suit the wall width without cutting, making installation straightforward where a longer or adjustable duct is required.
With no electrical supply, fans or moving parts, the vent works continuously using natural air and vapour pressure differences. An anti-draught vapour-permeable membrane allows moisture-laden air to pass outwards while helping to minimise incoming draughts, reducing the humidity conditions that contribute to surface condensation and mould growth.
Why choose the 100mm telescopic Perma-Vent?
The 100mm model combines a compact duct size with a free area of 7,283mm² and maximum water vapour transmission of 1–1.3 litres per 24 hours at 20°C. Internal and external fly screens help prevent insects entering through the vent, while the low-profile grilles provide an unobtrusive finish.
If you require greater passive ventilation capacity, consider the PermaPROTECT Passive Air Vent 150mm (Telescopic), which has a larger free area and higher maximum water vapour transmission.
For walls where an adjustable 300–550mm duct isn't required, our standard Perma-Vent Condensation Control Vent 100mm uses a 350mm duct that can be cut to suit the wall thickness.
What’s included?
- 100mm telescopic duct adjustable from 300mm to 550mm
- Anti-draught vapour-permeable membrane
- White internal grille with fly screen
- External grille with fly screen in your selected colour
- Installation instructions
The external grille is available in white, dark grey or terracotta.
Installing the 100mm Telescopic Perma-Vent
Choose a suitable position on an external wall close to the area affected by condensation, checking first for pipes, electrical wiring and other obstructions. As a general guide, passive vents should be positioned at high level, around 150mm to 300mm below the ceiling.
Use a 107mm (4.25") core drill and form the hole at a slight downward angle towards the outside of the property to help prevent external water running inwards. Once the wall thickness has been measured, simply adjust the telescopic duct between 300mm and 550mm to suit. Unlike a standard cut-to-length duct, no cutting is required.
Permagard - Condensation Control Experts
At Permagard, we stock a range of ventilation systems for different properties and condensation problems. If you're unsure which type or size of vent is most appropriate, our technical team can provide free expert guidance on 0117 982 3282.
You can also read our guide to ventilating a house or explore our complete range of ventilation and condensation control products.
Features
- Telescopic duct adjusts from 300mm to 550mm without cutting
- Compact 100mm passive ventilation unit
- Free area of 7,283mm²
- No electricity or moving parts required
- Anti-draught vapour-permeable membrane
- Fly screens fitted to the internal and external grilles
- Low-profile, unobtrusive grille design
- External grille available in white, dark grey or terracotta
- Easy retrofit installation using a core drill
