SEMCO Liquid Membrane application to enclose asbestos

Solution for Asbestos at ULYSSES S. GRANT HIGH SCHOOL

Portland Public Schools needed a solution for asbestos that would be safer, as well as, more time and cost effective than standard remediation. They trusted SEMCO to engineer a solution.


Portland Public Schools approved a $158 million dollar investment, toward a full modernization of Grant High School, to begin in the summer of 2017. The footprint and exterior facade were to remain the same to preserve the rich history, of the school, built in 1924. The interior of the building was modernized with a focus on indoor environmental quality, sustainability and historic preservation. A challenge faced is a magnesite concrete which contains a form of white asbestos in addition is a soft concrete and ultimately not suitable as a substrate for public traffic. The magnesite concrete was present in the staircases and areas of the structural flooring that cannot be removed, spanning 18,000 sq ft of the 300,000 sq ft project.

The overall modern design of the interior included polished concrete wherever possible. Mahlum Architecture was seeking possible options of a finished surface that can be applied over the Magnesite to strengthen it and encapsulate to neutralize the effects of the Magnesite.  If all this could be accomplished without damaging the Magnesite they stood to save on the time and cost of asbestos remediation. SEMCO’s Liquid Membrane and X-Bond Seamless Stone delivered on all accounts.  X-Bond also had the customization abilities to blend well with the polished concrete on the project and compliment Mahlum’s design.

Exploring Alternatives

Where demolition was possible it was completed, however like all asbestos laced materials uncontrolled contact, disturbance, or removal would begin the process of dispersing asbestos into the air. There were no alternatives to the SEMCO Liquid Membrane and X-Bond Seamless Stone as an applicable topical surface hardener and encapsulation system. No product or company would guarantee their performance where as SEMCO has been known to tackle project of this nature all across the world.


Mahlum Architects began collaborating with SEMCO Surface Engineers in 2016 to establish the parameters needed toward a solution. The following parameters and responses were established by Mahlum and SEMCO:


  • 320 psi or greater, no reinforcement fabric and SEMCO Liquid Membrane is required
  • Between 320 psi and 280 psi, reinforcement fabric and SEMCO Liquid Membrane is required
  • Below 280 psi, substrate must be removed and replaced

Upon completing site tests of the magnesite concrete the surface averaged between 280 and 320 PSI therefore enabling the SEMCO solution of strengthening the substrate with its X-Bond Seamless Stone to be viable with the use of a reinforcement fabric suspended with the SEMCO Liquid Membrane.


SEMCO’s innovative surface engineering team were intrigued by this challenge and got to work testing the details of our proposed solution. In the end they drew up a plan that effectively addressed all of the project’s needs:

  • Eliminate the need for costly asbestos remediation
  • Avoid any sanding or dust with the existing magnesite, to keep exposure to a minimum
  • Engineer methods to increase psi of the magnesite so it is prepared to receive a new surface
  • Provide a finished surface floor to blend with polished concrete on adjacent areas
  • Provide a finish that would be suitable to apply to stairs
  • A durable modern finish to compliment their blended design of old and new
  • An environmentally sustainable product for LEED accreditation
  • 10 Year Warranty