Monarflex DPM Polyethylene Damp Proof Membranes

Monarflex 1200 Gauge Damp Proof Membrane

Monarflex 1200 Gauge DPM is a loose laid, polyethylene damp proof membrane for horizontal ground supported or suspended slab applications without hydrostatic water pressure. 0.3mm thick and available in 2 x 25 m & 4 x 25 m roll size.

Features & Benefits

  • High elongation at break
  • High resistance to tearing
  • Safe and clean to handle
  • Chemically stable – no volatiles to leach out
  • Joints and seals easily
  • High water vapour resistance

Product Availability

Monarflex® 1200 Gauge DPM is manufactured from a blend of polyethylenes, which remain flexible at low temperatures, stable at high temperatures and are resistance to ageing. The membrane is 0.3 mm thick and available in two roll widths.

Product Code Description Roll Size
3100404 Monarflex 1200 Gauge 2m x 25m
3100405 Monarflex 1200 Gauge  4m x 25m


Product Data and Performance

Product Data
Material: LDPE
Roll Sizes: 2 x 25 m, 4 x 25 m
Colour: Black
Weight/unit area: 265 g·m-2
Membrane Thickness: 0.30 mm (1200 gauge)
Water Vapour Resistance: 302 MNsg
Equivalent Air Thickness: Sd = 120m

Resistance To Puncture: The products have a good resistance to puncture. On smooth or blinded surfaces they will not be damaged by normal foot or site traffic 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® 1200 Gauge DPM damp-proof membrane is manufactured to last the lifetime of the construction provided it is correctly installed and not damaged by subsequent building operations. 

Installation Details

Monarflex® 1200 Gauge DPM 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® 1200 Gauge 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® 1200 Gauge DPM 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® 1200 Gauge DPM, 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 Xtra-Load® Diamond or Monarseal MRX self-adhesive, bituminous membranes with an overlap of 150mm on each surface.

Detail work should be completed first. Once completed, Monarflex® 1200 Gauge DPM 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.

    Contact Icopal 0161 8654444

    Find Local Support

    To discuss your project in more detail please contact
    Your Local Area Manager


    Technical Support


    0330 123 4585



    Sales Enquiries & Orders


    0843 224 7400


    0843 224 7401


    Latest News

    A new faster, safer, stronger and lighter metal tile solution from BMI


    Band of Builders and BMI team up for community project


    The search is on for the BMI Apprentice of the Year 2020


    Oscar heads for the limelight


    BMI helps Children in Need keep young people safe


    Everyone's a winner - that's the truth!


    This site uses cookies in accordance with our Website Privacy Policy. By continuing to browse the site you are agreeing to our use of cookies. To browse without the use of cookies, you can opt-out as explained in our Website Privacy Policy or adjust your cookie settings for your browser

    Icopal: We Protect Your Building