Unroll one width of the Monarflex radon barrier membrane after determining the most effective method of covering the area. RMB350 is laid with the red side facing upwards. Reflex Super is laid with the sand-coloured side facing upwards.
Apply the appropriate 30mm double-sided sealant strip (Necobond™ when sealing Necoseal radon barrier membrane, or Monobond RT™ when sealing RAC, Reflex Super, RMB400 or RMB350). Leaving the backing paper on, lay the next width of membrane overlapping the first by 150mm.
Remove the backing paper from the sealant tape and join the top sheet to the bottom sheet by applying pressure with a hand roller. When the weather is cold keep the tape in a warm place until needed, and if necessary apply a little hot air but never use a naked flame.
It is preferable that radon barrier membranes are protected as soon as possible after installation to reduce the risk of damage that may be caused by following trades and/or during the concrete pour. The degree of risk will vary depending on the construction method being used and the level of supervision and technical control on site.
General guidance on radon barrier membrane selection