Visqueen Ultimate RadonBlok 400 is a flexible 0.4mm thick high performance co-polymer thermoplastic membrane. The product is purple in colour and supplied 4m x 25m in centre fold format. Other sizes and formats are available on request including single wound i.e. no folds.

Quick Links - Click To Jump To Section:

   
• Approvals and Standards
• System Components
• Storage and Handling
• Preparation
• Installation
• Usable Temperature Range
• Additional Information

Approvals and Standards

• Third party accreditation (IAB certificate 05/0214)
• Conforms to the specification requirements of BR 211:2023
• CE Mark EN 13967:2012
• Quality Management System ISO 9001:2015
• Occupational Health and Safety System ISO 45001:2018
• Environmental Management System ISO 14001:2015

System Components

• Visqueen Ultimate RadonBlok Double Sided Tape, 30mm x 30m
• VisqueenPro Single Sided Tape, 75mm x 25m
• Visqueen GR Lap Tape, 150mm x 10m
• VisqueenPro Detailing Strip, 300mm x 10m, 500mm x 10m
• Visqueen Preformed Units
• Visqueen Top Hat Units
• Visqueen Radon Sump

Storage and Handling

Visqueen Ultimate RadonBlok 400 should be stored horizontally, under cover in its original packaging.

Care should be taken when handling the product in line with current manual handling regulations.

Preparation

Visqueen Ultimate RadonBlok 400 should be installed on a smooth continuous surface e.g. grouted beam and block floor, a compacted blinding layer e.g. 50mm thick sand blinding, or smooth concrete blinding. The substrate should be free from irregularities such as voids or protrusions.

The membrane can be cut with a sharp retractable safety knife or robust scissors.

When installing the membrane in demanding site conditions, use Visqueen GR Lap Tape in place of Visqueen Pro Single Sided Tape.

Installation

Visqueen Ultimate RadonBlok 400 should be loose laid on the substrate. The membrane should be clean and dry at the time of jointing. It should be overlapped by at least 150mm, bonded with Visqueen RadonBlok Double Sided Tape and sealed with Visqueen Pro Single Sided Tape.

Alternatively lap joints can be heat welded to achieve an effective seal. Welded lap joints can be less than 150mm provided the joint integrity is not compromised.

Airtight seals should be formed around all service entry points. Visqueen Preformed Top Hat Units should be used for sealing service entry pipes. The base of the top hat and the upstand should be bonded using Visqueen RadonBlok Double Sided Tape and sealed with Visqueen Pro Single Sided Tape. The upstand should be secured with the supplied jubilee clip.

Forming an effective barrier to radon may give rise to complex three-dimensional detailing where, it is recommended Visqueen Preformed Units are used e.g. corners. Alternatively Visqueen Pro Detailing Strip can be used to seal awkward junctions.

If the membrane is punctured or perforated a patch of the same material should be lapped at least 150mm beyond the limits of the puncture and bonded with Visqueen RadonBlok Double Sided Tape and sealed with Visqueen Pro Single Sided Tape. Alternatively a patch can be formed using Visqueen Pro Detailing Strip and lapped at least 150mm beyond the extents of the puncture.

Long periods of exposure to ultraviolet light will reduce the effectiveness of the membrane. The membrane should be covered by a protective layer immediately after installation to prevent damage from following trades, ultraviolet light, etc. Care should be taken to ensure that the membrane is not punctured, stretched or displaced when applying a screed or final floor covering. A minimum thickness of 50mm screed is recommended.

When reinforced concrete is to be laid over the membrane the wire reinforcements and spacers must be prevented from puncturing the membrane. Where there is a high risk of potential damage, the membrane should be covered with Visqueen TreadGUARD protection, screed, or other approved protection material before positioning the reinforcement.

When used in full radon protection areas, a Visqueen Radon Sump or subfloor ventilation system maybe required.

Usable Temperature Range

It is recommended that Visqueen Ultimate RadonBlok 400 and all associated system components should not be installed below 5°C.

Additional Information

• Where ground gas protection is required to BS 8485:2015 + A1:2019, use Visqueen Gas Barrier system
• To assist build sequencing, Visqueen Zedex CPT DPC is available for radon protection through the wall constructions
• For suspended beam and block floor detailing see RADBLOK-01
• For ground bearing slab detailing see RADBLOK-14
• Visqueen Preformed Top Hat Units should be used at service pipe penetrations see RADBLOK-51
• For internal and external corners Visqueen Preformed Corner Units should be used
• To seal around steel columns use Visqueen Pro Detailing Strip see RADBLOK-52
• For additional detailing information, contact Rawlins Technical on 0113 2455450 (option 2) or send a message to [email protected]