Radon Barrier Protection Strategy - Necoflex

Sealing Services and Structural Penetrations

Seal all service and structural penetrations using the most appropriate method as outlined below:

Monarflex Top Hats


 Monarflex Top-Hat units

Monarflex Top-Hat Units

Monarflex Top-Hat units with retention clips are available to seal 110mm diameter pipes and ducts. Radon, air and moisture resistant joints are effected using Monobond RT™ or Necobond™ sealant tape.






Monarflex  MRX Easi-Flash Self-Adhesive Radon Flashing


 Easi-Flash Self-Adhesive Radon Flashing 150

Easi-Flash Self-Adhesive Radon Flashing

Easi-Flash™ Self-Adhesive Radon Flashing can be used for a wide range of sealing applications.

Prepare steel and concrete substrates using Icopal SA Primer. Cut sections of Easi-Flash™ Self-Adhesive Radon Flashing to the required length. Remove the protective release film and apply the self-adhesive side onto the prepared surface.

Lap 150mm to the Monarflex radon barrier membrane and the remaining to the steel or concrete (roll width is 300mm). The laps should be well rolled with a firm pressure to ensure complete adhesion and continuity. 

Sealing around steel columns 




Easi-Pour Liquid Radon Sealant


 Easi-Pour Liquid Radon Sealant 150

Easi-Pour Liquid
Radon Sealant

Easi-Pour Flexi-Mould 150

Easi-Pour Flexi-Mould













Easi-Pour™ Liquid Radon Sealant is recommended for sealing service penetrations, structural columns and irregular profiles of any shape or diameter. It is particularly suitable for multiple pipe penetrations, corrugated twin-wall ducts, and long radius bends.

(i) Ensure that the substrate has been well compacted before dressing the Monarflex radon barrier membrane around the penetration(s) to be sealed. A 30mm space should be left between penetrations. Where possible, cut the membrane close to the penetration to help contain the sealant until it has cured. Gaps can be closed if required using Easi-Flash™ Self-Adhesive Radon Flashing.

(ii) Remove any moisture or dirt from the surface of the radon barrier membrane and penetrations before sticking the Easi-Pour™ Flexi-Mould formwork in place. The formwork is flexible and has a pre-applied self-adhesive tape to facilitate bonding to the top of the radon membrane. Carefully position the formwork around the services, maintaining uniform spacing and ensuring at least 30mm of radon membrane will be covered by the Easi-Pour™ Liquid Radon Sealant.

(iii) After preparing all services and penetrations in advance, mix the Easi-Pour™ Liquid Radon Sealant as directed on the container and fill the formwork to a depth of at least 30mm. No trowelling is required as the sealant will flow around the penetration and find its own level. Working time is approximately 15 minutes. Curing time is approximately 24 hours at 20oC ambient temperature. The sealant should be protected from rain until it has cured and should always be covered by a concrete or screed layer. The Flexi-Mould formwork is permanent.

    Necoflex - Ireland's most complete range of radon barrier membrane systems, scaffold sheeting,  temporary roof covers, debris netting and acoustic systems