Visqueen Gas Barrier has been developed specifically for speed and ease of installation and the following general guidelines should be adopted:

Installation Guidelines
 

Visqueen Gas Barrier and ancillary components must be installed in accordance with the recommendations of Building research establishment BRE No:211 :Radon: guidance on protective measures for new dwellings" and BRE No:212"Construction of new buildings on gas contaminated land".

This product is not intended for use where there is a risk of hydrostatic pressure.

Laying the Barrier
 

Visqueen Gas Barrier should be installed on a blinded or smooth surface allowing adequate overlap for jointing between the sheets and avoiding bridging (i.e. areas of unsupported membrane).

in order to provide a continuous barrier the membrane should be taken up the walls to the Damp Proof Course level and incorporated beneath it in the inner skin.

Visqueen Gas Resistant (GR) DPC should be installed in accordance with BS 8215:1991, BS 8000: Part 3, 1989 and BS 5628: Part 3: 1985. All horizontal DPC's must be bedded on both sides with fresh mortar. All DPC's must project through the full width of the wall, including any externally applied rendering and project 5mm beyond the finished external face. All cavities must be kept clear of mortar droppings and other debris. Any mortar droppings reaching the DPC's must be removed before they harden, avoiding the use of sharp objects for removal.

Jointing
 

Visqueen Gas Barrier 150mm and bonded with Visqueen Double Sided Tape. This joint should be secured with Visqueen Foil Backed Girth Jointing Tape. Ensure that the membrane is clean and dry at the time of jointing.

Perforations or punctures in the sheet should be covered with another part of the sheet and have an overlap of at least 150mm and the laps sealed with Visqueen Double Sided Tape and secured with Visqueen Foil Backed Girth Jointing Tape.

Airtight seals should be formed around all service entry points. Pre-formed Top Hat Units are available for sealing around pipe entries. The base of the pre-formed unit should be sealed using Visqueen Double Sided Jointing.

Covering
 

Visqueen Gas Barrier should be covered by a screed or other protective layer as soon as possible after installation. Care should be taken to ensure that the membrane is not punctured, stretched or displaced when applying the screed or concrete. A minimum thickness of 50mm screed is recommended.

When reinforced concrete is to be laid over the barrier, wire reinforcements must be prevented from contacting the barrier. It is recommended that the barrier is covered with screed before positioning the reinforcement.

When under floor heating is being installed, it is recommended that the barrier is positioned between the blinded hardcore and insulation to protect the installation from moisture and to avoid any risk of overheating the membrane.

External and internal corners should be rounded. Where this is unavoidable then the angles must be strengthened with a 300mm wide strip of Visqueen Gas Barrier.

Storage and Handling
 

Visqueen Gas Barrier is classified as non hazardous when used in accordance with the relevant Code of practice (CP 102 1973). The product is chemically inert and is not affected by acids and alkalis that may be present in the sub-oils.

Exposure to ultraviolet light will embrittle the product. The material is therefore recommended for uses where it will be exposed to long periods of outdoor weathering. However, weathering will not occur when the membrane is installed in accordance with CP102 1973.

Care should be taken to avoid accidental damage when handling Visqueen Gas Barrier on site.