Design Guide For Hot Melt Liquid Roofing Systems

Design Guide

Parabit Hot Melt Waterproofing Systems consist of a tough and very flexible monolithic waterproofing membrane manufactured from a special blend of bitumen, synthetic rubbers, polymers and other additives, which when combined with a reinforcing fabric/grid and protection sheet, is ideal for use in protected roofs, plaza decks and green roof installations.

Designed for concrete substrates, Parabit Hot Melt Waterproofing Membranes provides the optimum waterproofing solution, where large roof areas can be covered very quickly permitting the progression of other trades internally.

Parabit is available in two systems:

  • Parabit Duo – This hot melt system is applied using two coats of the hot melt compound.
    .
  • newParabit Solo – This hot melt system is applied using a single coat of the hot melt compound, as a consequence Parabit Solo offers an increase in installation speed and reductions in labour costs.

To find out more about each of these system, please click on the appropriate buttons below.

  • Typical Roof Scenarios - Parabit Duo Systems

     

    Roof Types

    There are generally four types of roof in which Parabit Duo Hot Melt flat 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 DUO 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-DUO-Plaza-Podium-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-DUO-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-DUO-Intensive-Green-Roof
  • 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
  • Hot Melt Code of Practice January 2014 (Liquid Roof Waterproofing Association)

    Zero Pitched Falls

    Hot Melt Monolithic Membranes may be laid to zero pitched falls in accordance with certification from the British Board of Agrément (BBA). In such applications thermal calculations should be carried out in accordance with ETAG 031 (Guideline for European Technical Approval of Inverted Roof Insulation Kits). Further guidance can be found in the BBA Information Bulletin No. 4 ‘Inverted Roofs – Drainage and U-Value Calculations’.

    Zero pitched roofs are defined as flat roofs with a slope between 0 – 0.7°. It is essential to identify suitable drainage points to facilitate the effective removal of rainwater. Existing structures may require a detailed analysis to determine overall and local deflection as well as the direction of falls. It is considered good practice to design new roofs with a 1:40 slope to compensate for future settlement or deflection.

    Ponding Water

    Flat roofs are usually constructed with slight falls, typically 1:80, which allow water to drain away. Minor constructional variations in the plane of the surface will allow the collection of water which has no way of draining. It is therefore advisable to design falls greater than the required finished falls to allow for construction tolerances and dead and imposed loads.

    However, Hot Melt Monolithic Waterproofing systems are not constrained by the same falls requirements as warm flat roofs, where the waterproofing is the upper visible layer. Hot Melt Monolithic Waterproofing systems are commonly constructed as inverted roofs, the waterproofing is beneath the insulation and any applied finish. A loose laid water control layer is typically installed above the insulation and beneath the ballast/paving/green roof layer, this controls the travel of water within the roof build-up enabling drainage at insulation level and deck level.

    NOTE: for the water control layer to operate effectively, the inverted roof should be designed with a positive fall and in accordance with BBA Information Bulletin No. 4 and the manufacturer’s instructions (Hot Melt Code of Practice January 2014 - LRWA).

Contact Icopal 0161 8654444

Find Local Support

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

 

Technical Support

Telephone:

0330 123 4585

Email: technical.uk@bmigroup.com

 

Sales Enquiries & Orders

Telephone:

0843 224 7400

Fax:

0843 224 7401

Email: sales.admin@bmigroup.com

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