R Series Rails are high quality, fully adjustable support systems for rooftop unit vibration isolation. R Series Rails can be supplied as individual rails in pairs or unitized. R Series Rails are ideal for supporting equipment that does not require a full perimeter curb or ductwork going through the roof. Each custom-built unit incorporates both the rail and spring isolation into one complete structure. VMC engineers design each rail to custom fit any rooftop mechanical equipment. 

R7200 2" deflection spring rails can be specified to compensate for large floor spans, and spring pockets are positioned within the rail at the correct load points for proper support. All spring pockets incorporate a minimum 1/4" elastomeric cup or pad in series with the spring to provide optimum isolation efficiency.  

Fully flashable rooftop rail support system also saves the contractor unnecessary labor costs. The rail and rooftop unit can be fully installed and adjusted before the roof is sealed, eliminating the possibility of any damage to a finished roof. 

Leveling of the rooftop unit is accomplished easily as all spring pockets are accessible from around the outside of the rails. All springs are color-coded for ease of identification, and any spring can be removed and replaced with the rooftop unit installed. Once adjusted and leveled, the rooftop unit becomes free floating - completely isolated from the building structure, while completely restrained to it.

Features & Benefits

  • Access covers are easily removable for spring adjustment or replacement
  • Spring pockets are fully adjustable and offer deflections up to 3". Each pocket is positioned within the structural rail frame
  • Upper structural tubes support equipment while "floating" on spring isolators
  • CCA grade plywood covers structural steel frame and allows for complete roofing of the rail system. Structural steel frame allows for direct attachment to roof structural steel and mechanical equipment


  • HVAC rooftop equipment such as RTU's, fans, air-cooled condensing units and condensing units




The engineers we employ hold the highest industry-recognized credentials in structural analysis, elastomer development and system dynamics.


We are the first ISO accredited PCA ISO-17065, third-party certification body for special seismic certification of non-structural building components and their mounting configurations by the ICC’s International Accreditation Service.

Test & Measurement

We are the only ISO 17025:2005 Accredited Seismic Simulation Test Laboratory with a triaxial shake table owned and operated by California licensed Structural engineers.

Testing Services Update
DCL now offers Nuclear Qualification and Testing services.

In partnership with Greenberry Industrial, we now offer testing services that meet the requirements of ASME NQA-1.

Call for more information.