Structural Waterproofing

Monarflex Ultra 250 & 300 Damp Proof Membranes

Monarflex® Ultra DPM's are intended for use as a loose-laid damp proof membrane in solid concrete ground floors not subject to hydrostatic pressure, to protect buildings against moisture from the ground.  

Features & Benefits

  • High tensile strength
  • High resistant to tearing
  • Designed to withstand foot traffic.
  • Use for housing or commercial build
  • Compatible with all forms of DPC’s
  • Joints and seals easily
  • High water vapour resistance.

Product Availability

Monarflex® Ultra 250 & 300 Damp Proof Membranes consist of a reinforcing grid of 0.38 mm polyester (PET) thread with films of extruded low density polyethylene (LDPE) laminated on both sides to form a monolithic membrane. This process gives Monarflex Ultra range exceptional strength, and a very high tear and puncture resistance. The reinforcing grid is coloured green to aid site inspection.

Product Code Description Roll Size Roll Weight
3002789 Ultra DPM 250 25m x 2m 14kg
3002788 Ultra DPM 250 25m x 4m  28kg
3002776 Ultra DPM 300 25m x 2m  16kg
3002777 Ultra DPM 300 25m x 4m 32kg


Product Data and Performance

Product Data  
  Ultra DPM 250 Ultra DPM 300 
Roll Sizes: 2 x 25 m, 4 x 25 m 2 x 25 m, 4 x 25 m
Colour: Clear with Green
Reinforcement Grid
Clear with Green
Reinforcement Grid
Membrane Thickness: 0.25 mm (1000 gauge) 0.30 mm (1200 gauge)
Water Vapour Resistance: 540 MN·s·g-1 540 MN·s·g-1

Resistance To Puncture: The products have a high resistance to puncture. On smooth or blinded surfaces they will not be damaged by normal foot or site traffic (eg wheelbarrows) but care must be taken to avoid damage during installation, particularly when handling building materials and equipment over the surface and when placing concrete or screeds, since they can be punctured by sharp objects.

Resistance To Moisture: The membranes and the methods of jointing provide an effective barrier to the passage of moisture from the ground and will enable a floor to comply with the requirements of the national Building Regulations, if installed in accordance with the manufacturer’s instructions.

Durability: Monarflex® Ultra damp-proofing membranes are manufactured to last the lifetime of the construction provided they are correctly installed and not damaged by subsequent building operations.

Compatibility: Monarflex® Ultra DPM's are fully compatible with the range of Icopal damp-proof courses and membranes. 

Installation Details

Monarflex® Ultra Damp Proofing Membranes should be laid with overlaps of at least 150mm, and sealed to produce a water-proof and vapour-proof joint. This can be achieved with the use of Monobond double-sided sealant tape.

The dpm should be continuous with the damp-proof course. Where Monarflex® Ultra DPM and the dpc meet, they should be overlapped a minimum of 100mm and a sealed joint formed with an appropriate sealant tape, such as Monobond. Ensure the dpc is compatible with the dpm and sealant tape.

When laid below the slab Monarflex® Ultra Damp Proofing Membranes  should be laid on a bed of material which will not damage the membrane. When placed above slab, the surface should be free from debris and any projections which may damage the membrane.

Repair: Any damage must be repaired using patches of Monarflex® Ultra, extending a minimum 150mm from the puncture and continuously sealed with Monobond tape.

Penetrations: Where service ducts or pipes penetrate the membrane, joints are effected using Monobond LT sealant tape and top hat units with retention clips.

Complex junctions around penetrations such as, steel stanchions and concrete columns may be detailed and sealed by using a fully bonded membrane such as Imperma SBS hot-bonded, or Xtra-Load® Diamond self adhesive, bituminous membranes with an overlap of 150mm on each surface.

Detail work should be completed first. Once completed, Monarflex® Ultra DPM's may be laid and overlapped and sealed with Monobond LT sealant tape. The membrane should be rolled down firmly to ensure an effective bond and seal.

Steel, concrete and masonry surfaces should be primed with Xtra-Seal® QD Bitumen Primer prior to the application of the fully bonded membrane. 

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