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Provoid Gas Venting System consists of a 25mm geo - composite 'void former' that can be laid under the entire floor slab or, in strips at pre-determined centres, to suit the gas regime on site. Provoid 25 has been extensively tested as part of the DETR 'Partners in Technology' Report. When installed with the Provoid range of air inlets and outlets (please contact us for site - specific details), it can dilute harmful gases down to the required design concentrations for your site.

  • Only 25mm thick which results in less contaminated spoil to be removed compared to a 'pipe and gravel' venting layer
  • Flexible and easy to lay
  • Large rolls available for reduced installation times
  • Full range of ancillary products to ensure that the required 'air changes per hour' are achieved
  • Compatible with the Protech GM range of Gas Membranes

Provoid Gas Venting System

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Reinforced LDPE gas barrier incorporating aluminium foil. Protects against the ingress of Methane, Carbon Dioxide and Radon.



25mm geo-composite void former. Used with air inlets and outlets to dilute harmful gases and meet site requirements.

Protech GM Plus


Reinforced LDPE loose laid gas barrier that protects against the ingress of Methane, Carbon Dioxide and damp.

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  8:30am - 5pm, Mon - Fri

  01250 872 261

  01250 872 727


  A. Proctor Group Ltd., The Haugh, Blairgowrie, PH10 7ER



"As a roofing contractor specialising in the larger, more prestigious, type of project, we prefer to use only the highest quality products. Therefore we use Proctor Roofshield wherever possible; we have been using it for over 15 years, together with their condensation risk analyses and U-value calculations."

Mike Camilleri - Camilleri Roofing



Innovative Construction Products for Over 80 Years.