Project Type: Roofing, Waterproofing, and Wall Repairs

The Vital Structure: 

Roof Replacement Project, Balcony Waterproofing, Atrium Skylight and Exterior Wall Repairs


Vital Structures was retained to perform roof replacement engineering services for a pharmaceutical lab building in Cambridge MA. In addition to general wear and age, leaks had occurred into several mechanical penthouse areas in 2019. The exposed Atrium skylight had also reportedly been a source of ongoing leaks since the building was built in 2001 – past efforts had been unsuccessful in stopping the leaks.

Spalled Concrete at Reinforced Concrete Column
Heavily corroded steel reinforcing at spandrel beam

New R-30 EPDM roof system with ¼” per LF slope.


The building consists of several complex roof areas and varying wall systems. Two (2) mechanical mezzanine roofs were congested with ductwork and equipment for the pharmaceutical laboratories, resulting in ponding, obstructed drainage, and numerous roof penetrations. Vital Structures performed an evaluation of the existing EPDM roof system; including review of original design documents, infrared roof scan reports, destructive test cuts, peer review of the tenant mechanical upgrades, and programmatic leak testing of balconies, atrium skylight and rising walls.

  • Mechanical duct supports mechanically fastened (screwed) through the roof membrane.
  • Saturated roof assemblies with retained water under the roof membrane.
  • Roof membrane punctures and slope-to-drain deficiencies due to saturating and crushing of the roof assembly.
  • Masonry through-wall flashing deficiencies.
  • Failed/dislodged gaskets at exterior metal panel walls.
  • Skylight leaks corresponded with snowguard attachment areas, failed IGU butt-glazing joints, mullion joints/intersections, and skylight-to-rising wall connections (insulated metal panel and masonry walls).
  • Balcony slope-to-drain deficiencies, poor waterproofing terminations, and improperly installed drain components.

Our Solution

Vital Structures prepared an evaluation report and developed complete building envelope repair design documents, including the following:

  • Full roof replacement with R-30 roof assembly and ¼” per LF slope-to-drain and roof overflow drains.
  • New through-wall flashings and breathable masonry coating at rising walls.
  • New sealants using pre-compressed foam backers to replace metal panel gaskets.
  • Modification of HVAC duct supports and replacement of mechanical unit sleepers with insulated metal curb bases and anchorage improvements. 
  • New roof access doors, guardrails, and exterior walkover stairs etc. to meet increased flashing heights.
  • New skylight-to-wall transition flashings, modification of cheek wall panels, silicone mullion overlays, roof-to-skylight head flashings, snow-guard sealants, and IGU butt-glazing sealants.
  • New sloped topping slabs, PMMA waterproofing and IRMA paver system at balconies.
Coating installation at underside of the first-floor ribbed slab

Balcony PMMA waterproofing applied over sloped topping slab.

Coating installation at underside of the first-floor ribbed slab

New skylight cheek wall flashings.

Evaluate. Guide. Revitalize.

Let's Do Something Vital Together!

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