Periscope Extension Sleeve



  • MV251 Periscope
  • Provides ventilation beneath suspended floors
  •  Vertical adjustment for 3 to 4 brick courses
  •  Works in cavities from 50mm to 100mm
  • Can be used with MV250 Airbrick MV254 Vertical Adaptor and MV253 VentPipe Adaptor
  • Technical Data Sheet

Modern construction using higher levels of thermal insulation requires increased levels of ventilation within the building fabric to prevent the build-up of moisture and condensation. The increase in U-value requirements from 0.45 to 0.25 W/m2K for floors and from 0.45 to 0.35 W/m2K for walls in the revised Building Regulations Part L has heightened the importance of ventilation. With the increasing awareness of hazardous subsoil gases such as radon and methane the need for underfloor ventilation has become even more apparent. Glidevale have a range of underfloor through-wall and cavity wall ventilation products which meet the regulatory requirements and provide protection against driving rain birds rodents and large insects.

Additional information

Dimensions 0.4 cm


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SKU: MV251. Categories: , .