Protected Membrane Roofing Ballast Options & Flexibility

Ballast Options and Flexibility

One of the advantages of using MM6125® in a Protected Membrane Roof Assembly (PMR) is that once the membrane is installed owners and designers can take advantage of various ballast options (gravel, pavers and Garden Roof®) to suit a specific project’s needs. In fact, since MM6125 is keeping the structure watertight and monolithically applied directly to the deck, design professionals can combine ballast/assemblies with confidence knowing that drainage will occur at the deck level regardless of the transition between assemblies (i.e. gravel at the perimeter transitioning to a paver walkway that is separated from a vegetated space by a rock curb).


Typically requires crushed, graded stone placed over a stone filter sheet, rolled out over the insulation. In the field of the roof, a minimum of 10 lbs./s.f. ballast is required, with 20 lbs./s.f. needed at perimeters and at large penetrations.   

Contact Hydrotech for specific installation guidelines.


Ideal for installations where greater wind resistance is required (at building corners, perimeters or the whole roof) or when roof top traffic requires a more durable and walkable surface. 

Contact Hydrotech for specific installation guidelines.              


A lightweight alternative to the typical ballasted PMR Assembly is Hydrotech's Hydroguard® product. Hydroguard consists of Dow STYROFOAM® Insulation with a 3/8" latex modified cementitious layer that provides the necessary ballast, weighing only 4.5 LB/SF. Hydroguard Heavy is also available and consists of a 15/16” latex modified cementitious layer weighing 11 LB./SF. Click here for more information on Hydroguard.

Contact Hydrotech for specific installation guidelines.     


An esthetic and practical solution for the roof deck that is to be used as a terrace. Hydrotech provides the entire assembly from the MM6125 roof membrane to the architectural paver. Numerous paver sizes, colors and finishes are available. 


Hydrotech's Garden Roof Assembly takes the PMR roof to the next logical level - a vegetated roof. Reducing the urban heat island effect as well as a solution for stormwater management are only two benefits (of many) this assembly provides. This is sustainable, responsible architecture whose time is here.  

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