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hydrotech green roof


Roofing Applications

Monolithic Membrane 6125® (MM6125®) is a thick, tough, flexible, self-healing membrane for use in roofing applications. MM6125 is a special formulation of refined asphalts and synthetic rubbers. MM6125, the original hot fluid-applied rubberized asphalt membrane, has been successfully used worldwide by leading architects, engineers and owners on all types of horizontal and vertical structures including plazas, parking decks, planters, tunnels, bridges, mud slabs, foundation walls and roof areas...establishing an unbeatable track record of almost 60 years.

Hydrotech's Protected Membrane Roof Assembly (PMR)...

Conventional thinking in roof design...

As building structures became bigger, and the corresponding larger areas could not be effectively covered with steep roofs, the technology of the flat roof evolved. The water shedding slope was gone and roofs required a new element - waterproofing. To meet this requirement, the roofing industry began to mop asphalt membrane directly to the roof deck. As fuel costs increased back in the 1940's another demand was placed on the roof - energy efficiency. The need to counter energy loss dictated the addition of roof insulation. Since insulating materials of four decades ago were not water-resistant, the insulation had to be placed under the waterproofing membrane for protection. This system became known as the conventional insulated built-up roof system. With the conventional roof the insulation is protected from the exterior environment; however, the membrane is separated from the roof deck. Because it is no longer kept within the moderate temperature range that is near the building's temperature, the membrane is subject to a new set of conditions and stresses.

Roof Damage

Conventional roofs are susceptible to... Styrofoam over MM6125 with Ballast

A conventional roofing arrangement can leave the waterproofing membrane vulnerable to extreme and often sudden temperature changes, high summer roof temperatures, lower winter temperatures, freezing puddles, ultraviolet rays, physical abuse from heavy foot traffic and routine maintenance. Exposure to all of these elements weakens the integrity of the membrane. Once the membrane is compromised, moisture will eventually enter the insulation and cause a loss in its thermal efficiency. THERE IS A BETTER WAY... 

For more information on how a Protected Membrane Roof assembly can benefit your project, click here for an abridged version of our Planning Guide.  A full version can be requested by sending an email to



Typical Roofing Applications

Garden Roof® Assembly

Garden Roof® Assembly

Protected Membrane Roof (PMR)

Protected Membrane Roof (PMR)



PMR Metal Deck

PMR Metal Deck

The Ultimate Assembly®

The Ultimate Assembly®

Unconventional common sense in roofing technology...

The Protected Membrane Roof (PMR)...

A better way is possible because of DuPont™ Styrofoam™ Brand Insulation, a closed cell polystyrene that is highly moisture-resistant. Placed on top of Hydrotech's Monolithic Membrane 6125®, it offers protection from the harsh roof environment.

This arrangement of roofing materials - roof deck, waterproofing membrane, moisture-resistant insulation - is commonly referred to today as the Protected Membrane Roof (PMR) or Insulated Roof Membrane Assembly (IRMA). With such roofs, the membrane's temperature range and rate of temperature change are drastically reduced. By simply reversing the insulation and the membrane - insulation on top of the membrane rather than beneath - the cause of many roofing problems can be eliminated.


Advantages of the PMR Assembly...

In conventional roofing the exposed membrane can be easily damaged by physical abuse. Abuse caused by other trades, during construction, or after from maintenance to roof top HVAC units...or the occasional arrow shot in the air!  Obviously, in a PMR assembly, the insulation and ballast layer on top of the membrane helps to protect it from physical abuse. 

Mother nature can be brutal too!  From large temperature swings from day to night, freeze-thaw cycling, UV and ozone.

A study done by the U.S. Army, Corps of Engineers in the 1970's showed that on a PMR installation in Alaska, the roof membrane stayed within 15 °F of the deck temperature... year round.

MM6125 Unique Characteristics

  • MM6125 is a thermoplastic material – one component, 100% solids, NO solvents means no on-site cure failures, no two part mixing and no VOC restrictions.
  • MM6125 has a minimum 40% recycled content; validated by UL.
  • MM6125 conforms to all surface irregularities and bonds tenaciously to an acceptable substrate (i.e., concrete, steel, wood, etc.) eliminating lateral migration of water.
  • MM6125 is completely monolithic, no seams!
  • MM6125 is typically installed at 215 mils thick in the Fabric Reinforced Assembly. This is more than three times thicker than most other waterproofing membranes. Thickness is an important benefit in that MM6125 exhibits the ability to self-heal and better accommodate developing cracks in a concrete substrate.
  • MM6125 can be installed at temperatures as low as 0 °F (provided the substrate is clean, dry, free of snow and frost).
  • MM6125 detailing is simplified, with triple protection at all critical locations.
  • MM6125 is ideal for dead level installations; no slope required, just positive drainage.
  • MM6125 was developed to perform in a wet (submerged) environment.
  • MM6125 tie-ins from one days work to the next is easy, perfect for phased construction.

MM6125 Approvals/Certifications

  • Manufactured under ISO 9001:2015
  • CAN/CGSB 37.50-M89 (Canadian General Standards Board)
  • Applicable ASTM Test Methods (American Society for Testing and Materials)
  • BBA Approval (British Board of Agrément)
  • UL Class A Classification (Underwriter Laboratories)
  • UL validation of recycled content (Underwriter Laboratories)
  • FM Approval (Factory Mutual)
  • Miami-Dade County, FL Approval
  • Florida Product Approval
  • General Approval - City of Los Angeles
  • MEA Approval - City of New York