Telescopic (adjustable) underfloor ventilator to provide ventilation beneath suspended ground floors (equivalent area of 6000mm²).

Always to be used in conjunction with the Timloc Airbrick (1201AB).

The vertical height of the ventilator unit adjusts to suit between 3 and 5 brick courses (225-375mm) with a minimum cavity width of 50mm.

Extensive range of quick and easy to fit horizontal and vertical extension accessories (doesn’t restrict air flow through the ventilator):

  • horizontal front extension sleeve
  • vertical extension sleeve
  • duct adaptor
  • horizontal rear extension sleeve.

Features & Benefits

  • Special grille included to prevent the entry of vermin on telescopic underfloor vent
  • Very tough and robust material
  • Accessories don’t restrict airflow through the main telescopic underfloor vent unit
  • Purpose-made accessories eliminate the need for on site modifications
  • Lightweight and easy to handle
  • Material totally resistant to decay


  • Standard brick and block constructions
  • To be used to provide ventilation below suspended ground floors and should always be used in conjunction with a Timloc Airbrick (1201 AB)
  • To provide horizontal or vertical extension to a telescopic underfloor ventilator to accommodate different wall/cavity/brick courses

Technical Information

The NHBC recommend that underfloor ventilators are spaced at a maximum of 2 metre centres, with ventilators also positioned not more than 450mm from the ends of the wall.

As a minimum requirement ventilators should be positioned down two opposite sides of the building to create a cross flow action.  We recommend the good practice of positioning underfloor ventilators around the full perimeter of the building.

Telescopic Underfloor Ventilator (1201) – adjustable for a step of 3, 4 or 5 brick courses and presents an equivalent of 6,000mm² per unit.

Horizontal Front Extension (1203) – fits between the airbrick and upper front opening of the telescopic underfloor vent to accommodate external walls of more than 102.5mm thickness – up to 215mm (multiple units can be fitted and trimmed to suit wall thicknesses above this).

Vertical Extension Sleeve (1204) – fits between the upper and lower parts of the telescopic underfloor vent to accommodate a vertical step of more than 5 brick courses (multiple units can be stacked together to achieve required height).

Duct Adaptor (1205)  – fits onto the lower rear opening of the telescopic underfloor ventilator to allow a standard 110mm internal diameter soil pipe to be connected (compression fitting may be required).

Horizontal Rear Extension Sleeve Product (1206) – fits into the lower rear opening of the telescopic underfloor ventilator to accommodate cavity widths between 50-150mm – or internal walls of more than 100mm thickness (200mm max.).

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