Home > Companies > Manthorpe Building Products Ltd > G965 Dual Extended Telescopic Underfloor Void Ventilator

The Telescopic Underfloor Void Ventilator is designed to provide a clear airflow passage to a void beneath an insulated suspended floor.


  • The G965 offers a vertical telescopic adjustment of between five and eight brick courses without the need for an extension sleeve.
  • The horizontal outlet is long enough to bridge through an overall wall thickness of 350 mm without the need for an additional extension.
  • Offers a free airflow of 8000 mm² per vent (7600 mm² through G930).
  • The front aperture is designed for use with a G930 Combination Airbrick or it can be used in conjunction with a traditional clay airbrick, although this would reduce the overall airflow through the system.

Standard product features


  • The current and future requirements of Part L of the Building Regulations along with other standards and regulations have led to an increase in the depth of thermal insulation in suspended floors along with an increase in cavity widths to accommodate greater amounts of cavity wall insulation.
  • This has meant that clear access to an underfloor void may be as far as six or seven brick courses (525 mm) below the level of an airbrick and potentially as much as 350 mm from the outer face of the external leaf.
  • Traditional telescopic underfloor ventilators would not be able to achieve this without the use of additional vertical and horizontal extension sleeves.

NBS Specification

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This product is associated with the following NBS Create clause:
45-80-50/394 Ventilation ducts

NBS Specification

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This product is associated with the following NBS clauses:

Product specification

An important note about specifying



Manthorpe Building Products Ltd


+44 (0)1773 514200

Product reference

G965 Dual Extended Telescopic Underfloor Void Ventilator

Manufacturer details

Manthorpe House,
Brittain Drive,
Codnor Gate Business Park,
Derbyshire, DE5 3ND
Tel +44 (0)1773 514200
Fax +44 (0)1773 514261
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