Installation of Hot Melt Waterproofing Systems

Installation Manual - Parabit Solo Hot Melt Waterproofing System



Working conditions

Do not apply membrane if temperature is less than 0 °F (-18 °C) or to a damp, frosty, snow covered or contaminated surface.
Any surface dampness can seriously affect adhesion of the membrane. Residual excessive dampness within the substrate can result in blistering. After a period of rainfall, allow at least one full day of good drying conditions.

Pre-start / Pre-commencement

Co-ordinate the waterproofing work with other trades. The applicator should have sole right of access to the specified areas for the time needed to complete the application.

Protect adjoining surfaces not to be waterproofed against damage or spoiling. Protect plants, vegetation and animals which might be affected by waterproofing operations.

Warn personnel against breathing of vapours and contact of material with skin or eyes. Wear applicable protective clothing and respiratory protection gear where applicable. Refer to relevant material safety data sheet.

Keep flammable products away from spark or flame. Do not allow the use of spark producing equipment during application until all vapours have dissipated. Post, ‘NO SMOKING’ signs.

Maintain work area in a neat and orderly condition, removing empty containers, rags and rubbish daily from the site.

Refer to NBS J31 specification document for confirmation of system build up.

  • Substrate Preparation

    Density of Concrete

    The following are the types of concrete used in construction with their acceptability to receive the Parabit Duo or Solo Hot Melt System:

    • In-situ Concrete: Structural concrete will have a density of 2,160 kg/m³ to 2,500 kg/m³ and will retain 3 to 5% moisture by volume when cured. Concrete with high moisture content requires a minimum curing period of 28 days to ensure adequate drying.
      Low density concrete (less than 1,850 kg/m³) will create adhesion difficulties due to the friable / dusty nature of the surface.
    • Precast Concrete: Where the pre-cast concrete units provide a smooth and level surface, the joints between the units can be
      grouted in readiness to receive the specified PARABIT Hot Melt system. Joints should be locally reinforced using a strip of the
      PARABIT SOLO Angle Reinforcing Strip embedded into the PARABIT Hot Melt Compound. Where the surface of the units are
      not acceptable, a structural concrete layer above the pre-cast units will be required.
    • Concrete Block: For vertical applications, concrete block is acceptable. Joints should be flush pointed. A strip of the PARABIT
      SOLO Angle Reinforcing Strip should be installed into the 90°angle using PARABIT Hot Melt Compound.
    • Lightweight Structural Concretes are considered acceptable substrates when the density is between 1400 kg/m³ and 1800 kg/m³; retaining 5% to 20% moisture when cured.
    • Lightweight Insulating Concretes are not acceptable substrates.


    The concrete surfaces shall be of sound structural grade, and shall have a wood float or fine broom finish, free of fins, ridges, voids or entrained air holes. A steel trowelled finish or shiny surface is not acceptable. All knots and dust must be removed.

    Laitance: Loose concrete towards the surface of the concrete must be removed.

    Concrete shall be cured by water curing method. Pure sodium silicate curing compounds are acceptable.

    Contamination: All contaminants must be properly cleaned before application of the Parabit Hot Melt System can commence.

    Concrete shall be cured for a min. 28 days.

    Voids, rock pockets and excessively rough surfaces shall be repaired with approved non-shrink grout or ground to match the un-repaired areas.

    Form Release Agents used to facilitate removal of formwork from cast concrete can be transferred to the face of the concrete once the formwork has been struck. Such agents can detrimentally affect the adhesion of the monolithic membrane. As a result all agents transferred to concrete must be removed prior to application of the membrane. Furthermore, accelerators within the concrete can migrate to the surface leaving a shiny surface. These should be removed.

    Two-stage drains shall have a minimum 75mm flange and be installed with the flange flush and level with the concrete surface.

    Other Substrates

    • Plywood: All plywood substrates should be in accordance with BS EN 636, BS 5268-2 & BS EN 13986. All interlocking board joints should be locally reinforced using a strip of the PARABIT Angle Reinforcing Strip embedded into the PARABIT Hot Melt Compound.

    Bond Tests

    Before the Parabit Hot Melt Membrane is installed an adhesion test must be conducted to ascertain the suitability of the concrete surface. Bond tests are advised to the area to be coated that day prior to the main application.

    To complete the bond test, apply a small amount of primer to the cleaned and prepared area and allow to dry. Apply a small amount of the PARABIT SOLO Hot Melt Membrane and allow it to cool and embed a prepared section of Power Elastomeric 250 Sanded membrane into the hot compound, leaving an overhang of membrane to facilitate the pull test. If it is not possible to separate the hot melt sample from the substrate (resulting in destruction of the membrane), the adhesion is considered satisfactory. If the membrane can be easily peeled away from the deck, then the substrate is not ready and may require further preparation works.

    If the test patch is acceptable, protect the patch until the main area material is to be applied. The test material will re-act with the new material maintaining a monolithic membrane.


    Example 1: Successful bond test Example 2: Unsuccessful bond test
    Successful-bond-test Unsuccessful-bond-test


    Common reasons for peel test failures:

    1. Surface laitance – loose, friable surface concrete that will require mechanical removal
    2. Damp substrate – wet concrete will impede adhesion. Efforts should be made to reduce the retained volumes of water within the slab. A high penetrating primer (eg. Siplast Primer) may also be required.
    3. Damp substrate – evaporation from moisture retained within the concrete slab can lead to peel test failure and blistering. A high penetrating primer (eg. Siplast Primer) may also be required.
    4. Surface contamination – dirt, debris, dust curing agents, form release agents can all impede membrane adhesion. All should be removed prior to repeating test.
    5. Smooth surface finish – power floated concrete finishes will be too smooth and will require mechanical scabbling.
    6. Primer – the primer should be allowed to dry naturally. Do not attempt to dry the primer using gas torches. 



    Parabit priming

    Prime all areas to receive the Parabit Duo or Solo Hot Melt System using Icopal Siplast Primer and allow to dry. Apply a thin coat and avoid pooling. Allow to dry thoroughly before over coating.
    The primer should be applied to the prepared concrete surface by brush or roller at an approximate coverage rate of 0.25 L/m² (coverage rate will vary subject to substrate porosity).
    Drying time for the primed surface will be 1 to 3 hours dependent upon ambient conditions and substrate porosity.


  • Preparation of the Parabit Hot Melt Compound

    Parabit Hot Melt CompoundPrior to insertion to the bitumen boiler, remove all external cardboard packaging from the individual hot melt blocks and dispose carefully.

    Heat the blocks of Parabit Hot Melt Compound in the thermostatically controlled bitumen boiler to a temperature of approximately 180°C, prior to transferring to the application buckets. Avoid overheating.

    The operatives must be fully trained in the safe operation of the bitumen boiler and it should not be left unattended

  • Membrane Application: Details Area

    Prime all surfaces to receive the waterproofing membrane with Xtra-Seal QD Bitumen Primer, and allow to dry.

    Upstands / Angle Changes

    Pre-cut lengths of PARABIT SOLO Reinforcing Fabric and Power Elastomeric 250 Sand to the appropriate size to accommodate the upstand detail.

    Mechanically fix a 50x50mm timber angle fillet at the base of all upstands prior to commencement of upstand detail. This will aid detailing providing a smoother transition of the waterproofing in the corner.

    Prime all surfaces at details to receive the waterproofing membrane, and allow to dry.

    Dress PARABIT Hot Melt Compound up the upstand using a pouring ladle/paddle and subsequently apply the prepared sections of Power Elastomeric 250 Sanded Capsheet. The membrane should extend onto the horizontal deck area a minimum of 200mm.

    Run a metal scraper over the excess hot melt at the overlaps to fully seal the membrane.


    To complete the detail Thermaweld Mineral Capsheet is to be installed, however:

    Prior to application of the Thermaweld Mineral Capsheet, the field area membrane should be installed, dressing onto the horizontal leg of the Power Elastomeric 250 membrane and achieving a full bond by using the Parabit Hot Melt Compound.

    For application of the field area, see page Typical Roof Scenarios section below.

    Note: For green roof projects, substitute Power Elastomeric 250 with Rootbar Sanded Capsheet.


    Once the field area is installed;

    The upstand detail should be completed by fully bonding, by torch application, Thermaweld Mineral Capsheet, ensuring a 5mm bead of bitumen extrudes at the edges. Dress down and on to the field area membrane a minimum of 250mm, ensuring a thorough bond is achieved.

    Note: For green roof projects, substitute Thermaweld Mineral Capsheet with Rootbar Mineral Capsheet.


    Where possible the upstand detail should return across the top of the parapet detail.

    Where terminating vertically, all upstands should be a minimum 150mm above the finished roof level and should be mechanically restrained beneath a termination bar and suitably pointed.



    Clamping Ring Rainwater Outlets

    Typically, clamping ring rainwater outlets are used with monolithic hot melt membranes. 


    Pre-cut a square section of Power Elastomeric 250 Sand membrane approximately 450 x 450mm and cut a circle in the centre of the membrane. Parabit-Solo-Clamping-Ring-Rainwater-Outlets-01

    Cut the membrane to the circumference of the outlet and press back the tabs in readiness to receive the hot melt compound.


    Pre-cut a square section of the Parabit SOLO Reinforcing Grid approximately 1 m x 1m and cut and remove a circle in the centre of the grid.

    Loosely lay the prepared reinforcement above the outlet, positioning the removed circular section centrally above the downpipe.


    Pre-cut a square section of Power Elastomeric 250 Sanded Membrane approximately 800 x 800mm and roll back to one edge of the underlying reinforcing grid.

    Pour Parabit Hot Melt Compound onto the reinforcing grid and spread using a scraper. Unroll the Power Elastomeric 250 Sanded Capsheet into the poured hot melt, ensuring the membrane is fully bonded

    Run a scraper along all edges. Parabit-Solo-Clamping-Ring-Rainwater-Outlets-05

    Cut a circle in the centre of the membrane.

    Star cut the membrane, turning the individual membrane tabs down into the neck of the clamping ring outlet, pressing them into the molten hot melt.

    Complete the detail by mechanically securing the clamping ring. Parabit-Solo-Clamping-Ring-Rainwater-Outlets-07

    Alternatively, install Icopal’s Roofgard Rainwater Outlet of the required diameter prior to installation of the PARABIT SOLO Hot Melt Membrane. Torch apply the bituminous flange to the primed concrete surface ensuring a full bond. Dress the PARABIT SOLO Hot Melt Membrane onto the membrane flange a minimum of 100mm. Please note, a slight watercheck could be created when dressing onto the membrane flange. 

    Expansion Joints

    The expansion joint detail is installed above the completed PARABIT SOLO Hot Melt Membrane.

    Install the PARABIT SOLO Hot Melt Membrane up to the expansion joint.

    Next, centre and loosely dress the Neodyl Joint Strip into the expansion joint, returning the two edges onto the PARABIT SOLO Hot Melt Membrane.

    Then, loose lay the Neodyl Chord into the expansion joint recess.


    Using the PARABIT Hot Melt Compound, bond each side of the Neodyl Joint Strip to the upper surface of the PARABIT SOLO membrane.


    Pre-cut a section of Thermaweld Mineral Capsheet and torch bond to the upper surface of the underlying Neodyl Joint Strip on one side and PARABIT Hot Melt Membrane.

    Care should be taken to ensure that only the Thermaweld membrane is torched.


    Pre-cut a second section of Thermaweld Mineral Capsheet and position over the expansion joint. Torch the edges of the sheet only. One edge will be above the existing section of Thermaweld membrane whilst the second edge will be above the PARABIT SOLO Hot Melt membrane on the opposite side of the joint. On completion the central area (above the Neodyl Expansion Joint) will remain loose and unbonded.

    Press the laps to ensure they are fully sealed and a bead of bitumen is visible.

    Note: For green roofs, Rootbar Capsheet Mineral should be used in lieu of the Thermaweld Mineral.



    Pitch Pockets

    Where there is an irregular shaped penetration through the roof structure, a “pitch pocket” detail can be used to achieve a watertight detail.

    Apply the PARABIT Hot Melt Membrane up to the designated penetration detail.

    A prefabricated galvanised steel former is used to act as a bund to contain the PARABIT Hot Melt Compound.

    Prime the metal former with Icopal QD Bitumen Primer and allow to dry. 

    Position the former around the penetration(s), ensuring the former is sized to allow overlap onto the PARABIT SOLO membrane beneath. The horizontal leg of the metal angle should face outwards.

    Ensure there are no gaps between formwork sections.


    Pour the PARABIT Hot Melt Compound into the pitch pocket detail in layers of 10mm thickness, building up the contents in 3 or 4 layers, until a satisfactory depth has been achieved.

    Where the pitch pocket detail is applied over bolt heads, ensure the hot melt finish is 50mm above the level of the bolt heads.

    Allow the poured PARABIT Hot Melt Compound to cool.

    Pre-cut sections of Power Elastomeric 250 Sand membrane and apply to the pitch pocket detail. The membrane should dress from the horizontal PARABIT membrane up over the metal former and onto the upper surface of the pitch pocket. Parabit-Solo-Pitch-Pockets-03
    Apply the pre-cut sections of membrane to all four sides of the pitch pocket detail. Parabit-Solo-Pitch-Pockets-04



    Rooflights shall consist of a pre-fabricated timber, masonry or concrete upstand kerb. Apply the Parabit Solo Hot Melt Membrane to the upstand kerb prior to installing the specified rooflight.


    Internal gutters shall be waterproofed in same manner as the main flat roof area, taking care to ensure all laps are fully sealed.

  • Membrane Termination

    Where terminating vertically, all upstands should be a minimum 150mm above the finished roof level (ie. ballast / pavers etc) and should be mechanically restrained beneath a termination bar and suitably pointed. The waterproofing system must be suitably terminated to the surrounding construction to prevent water penetration ‘behind’ the new waterproofing system.

    Depending upon the nature of the installation and construction, the membrane should be protected with a ‘Cover Flashing’. Alternatively, the membrane may be secured with a ‘Termination Bar’ which is then weatherproofed by pointing a suitable mastic sealant along the top edge between the construction and the Termination Bar.

    The waterproofing should finish on the vertical a minimum 150mm from the finished roof level, in accordance with ‘BS 6229:2003 Flat roofs with continuously supported coverings. Code of practice’. In the case of roofs with inverted roof insulation, paving or other coverings such as a green roof, the 150mm should be from the uppermost finished level, and not the level of the waterproofing..

    Cover Flashings

    Pre-cut any chases prior to application of the system. Cut new 25mm deep chases in all masonry upstands. These should provide a minimum 150mm upstand above the finished level of the roof. The new waterproofing is to finish flush with the bottom of the cut chase and mechanically restrained along the leading edge using a suitable termination bar. Install the new flashing, dressing into the chases provided. Cut, joint and dress the new flashing neatly. Temporarily secure the flashing and then point with a suitable sealant.

    Lead flashings should be installed in accordance with codes of practice and recommendations of the Lead Sheet Association.
    Alternatively, Icopal FormFlash lead-free flashing may be used instead, and installed in the same fashion.

    The flashing should provide sufficient coverage of the waterproofing, extending down a minimum 75mm over the waterproofing system..

    Termination Bar

    Depending on the method of installation and the type of termination bar used, the waterproofing membrane may first require mechanical restraint using the Icopal Fixing Bar. The termination bar is mechanically fastened to the wall at regular fixing centres. A suitable mastic sealant is applied behind the lip of the termination bar just prior to the final tightening of the fasteners. This provides a compression to the sealant ensuring that the detail is sufficiently weatherproof.

    termination-bar-arrangement-1  termination-bar-arrangement-2 termination-bar-arrangement-3 
    Termination Bar Arrangement - Membrane secured with Fixing Bar  Termination Bar Arrangement - Membrane secured with the Termination bar itself Cover Flashing Arrangement - Membrane secured with Fixing Bar 
  • Membrane Application: Field Area

    Application of the Hot Melt Compound

    Prime all surfaces to receive the waterproofing membrane with Icopal QD Bitumen Primer, and allow to dry.

    Above the primed surface, position and unroll the PARABIT SOLO Reinforcement Grid, overlapping adjoining roll lengths by minimum 75mm. Parabit-Solo-Field-Applicattion-01
    Position the Power Elastomeric 250 Sanded Capsheet above the unrolled reinforcing fabric by rolling out to the required length and rolling back on itself in readiness for application. Side laps should be positioned to be a minimum 100mm and end laps should be 150mm. End laps should be staggered to avoid excessive build-up of membranes. Parabit-Solo-Field-Applicattion-02

    Transfer the heated PARABIT Hot Melt Compound from the thermostatically controlled bitumen boiler to the ‘V’ lipped buckets, taking care when doing so. Appropriate PPE should be worn.

    Pour the heated PARABIT Hot Melt Compound through the PARABIT SOLO Reinforcement Grid at a coverage rate of 3kg/m².


    Apply the Power Elastomeric 250 Sand Capsheet into the final course of PARABIT Hot Melt and scrape / splice the membrane seams together with hot melt compound.

    Where the PARABIT Hot Melt System is left exposed at upstands and other details etc, Thermaweld Mineral Capsheet should be torch-applied, and used to protect the PARABIT Hot Melt System from UV damage.

    For green roof applications Rootbar Sanded Capsheet should be used as the protection layer, with Rootbar Mineral Capsheet used at all details.

  • Typical Roof Scenarios - Parabit Solo Systems

    There are generally four types of flat roof in which Parabit Solo Hot Melt Roofing System is used:

    Inverted Warm Roof

    Sometimes referred to as an ‘upside down’ roof, the thermal insulation is positioned above the roof covering, resulting in the roof covering, structural deck and ceiling being at a temperature close to that of the interior of the building.

    Since the insulation is above the waterproofing system the insulation must be water-resistant and it must be ballasted to prevent floatation of the insulation boards and to protect against wind uplift. Therefore, the flat roof deck must be capable of withstanding the additional loading of a ballasted roof.
    Read more about the design of Inverted Warm Roofs

    Parabit SOLO Warm Inverted Ballasted Roof

    Plaza / Podium Decks / Terraces/ Balconies

    Many modern buildings incorporate:

    • Landscaped or paved areas over basement or subterranean areas such as car parks. These areas are often used as recreation or circulation space between buildings. Being flat roofs they still require a durable waterproofing system to be installed
    • Terraces tend to be areas within the footprint of the building providing access for public traffic.
    • Balconies - A balcony is typically on the outside of a building accessed from a window or door enclosed by a suitable handrail.

    Read more about the design of Plaza / Podium Decks / Terraces/ Balconies roofs 

    Parabit SOLO Plaza Podium and Terrace Roof

    Green Roofs - Extensive

    Extensive green roof systems are generally intended to be viewed from another location as a decorative/ ecological feature. They are not normally used as a recreational space to be walked through or sat in and often have limited access used for maintenance only. Due to the shallower substrate depths of extensive systems, the plant choices are more restricted to drought tolerant species such as sedums, grasses, wildflowers and mosses.
    Read more about the design of Extensive Green Roofs

    Parabit SOLO Extensive Green-Roof

    Green Roofs - Intensive

    Intensive green roof systems are designed to be used as recreational spaces and often involve many features similar to traditional ground level gardens which can include paving, water features, lawns, shrubs and trees. These intensive 'roof gardens' are soil based multi layered systems and are so called because they are labour-intensive; requiring higher levels of irrigation, feeding, and other forms of maintenance compared to their extensive counterparts.
    Read more about the design of Intensive Green Roofs 
    Parabit SOLO Intensive Green Roof
  • Completion

    Quality Assurance

    Please note; the validity and the extent of the Icopal warranty will only apply where Parabit Duo or Solo components and accessories (or products made by others approved by Icopal prior to commencement of works) have been used. Any alterations to agreed system specifications shall render any warranty offer null and void.

    Furthermore, should the Parabit Duo or Solo Hot Melt Waterproofing System fail to be installed in accordance with the current guidelines (unless otherwise agreed), the warranty offer shall be rendered null and void.

    For Icopal ‘Insured System Plus’ guarantees installation shall be by an Icopal Parabit Duo or Solo approved contractor only.

    The roof will be inspected by an Icopal representative during works and then a final inspection is carried out on completion of the project. Sufficient notification to the Icopal representative should be given.

    Integrity Testing

    Upon completion of the Parabit Duo or Solo roof, it is the contractor’s responsibility to arrange an independent non-destructive integrity test to ensure the roof system is 100% watertight.

    If the independent report shows failure points, these should be repaired, and the roof retested.

    The independent third-party report showing that the system is 100% watertight should be forwarded to Icopal Limited when requesting an Icopal warranty.


    It is recommended that the roofing sub-contractor advise the main contractor or client when the roof area is 100% watertight and received formal certification to that affect. The roofing sub-contractor should formally handover of the designated roof area at this point. Subsequent damage sustained by the membrane after this point which is found to be a result of the main contractor’s or client’s activities should not be the responsibility of the roofing sub-contractor.

  • Tools & Equipment

    The following is intended as a basic list of tools and equipment and their operation necessary to install a Parabit Duo or Solo Hot Melt System. Depending on the project, other tools and equipment may be required.

    Additionally, these instructions are provided as recommended guidelines to follow to ensure proper performance of the equipment and successful installation of the Parabit Hot Melt Membrane. Icopal does not endorse or recommend any particular brand of equipment.


    • Thermostatically Controlled Bitumen Boiler: An air or oil jacketed bitumen boiler with thermostatic controls and continuous agitation.
    • Buckets: A galvanised metal ‘V’ lipped bucket with handles to facilitate transport and pouring of the Parabit bitumen compound. Buckets should be cleaned at the end of each working day.
    • Ladles: A long handle galvanised metal bitumen ladle for transferring/pouring the Parabit Hot Melt Compound.
    • Scraper: A metal scraper may be required.
    • Cutting Tools: Tools, such as a fixed blade utility knife, eg Stanley Knife, with both straight and hook blades. Large scissors may also be required.
    • Personal Protective Equipment: Gloves, Overalls, Goggles, Masks and other personal protective equipment (PPE) will be required.
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