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The mission of the Historic Resources Committee (HRC) is to identify, understand, and preserve architectural heritage, both nationally and internationally. HRC is engaged in promoting the role of the historic architect within the profession through the development of information and knowledge among members, allied professional organizations, and the public.

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Terrazzo with asbestos in the matrix

  • 1.  Terrazzo with asbestos in the matrix

    Posted 05-19-2020 09:21 AM
    Edited by Gregory Rutledge 05-27-2020 04:48 PM
    We are working on a project involving a 1950's addition to a 1930's structure, both are historically significant and we are trying to retain as much of the interior fabric as we can.  The black squares of the checkerboard terrazzo floor in the 1950's addition has tested positive for asbestos in the matrix.  This is something I have never encountered, nor has our contractor and we cannot find a subcontractor who will touch it.  We don't intend to do extensive repair, but we'd like to strip the years of wax and sealants, clean the floor and reseal.  Any suggestions on how to deal with this material?

    Greg R.

    Greg Rutledge, FAIA
    Hanbury | Architecture Planning
    Norfolk VA

    Thanks for your advice, everyone, you're responses are what I expected.  I'm not sure why we're having such a difficult time trying to get this floor stripped and sealed, other than a construction cost change order has been proposed to replace it and I don't want to lose the historic material.

    Stephanie:  The HazMat report says only the black terrazzo contains 5% Chrysoltile; category II non-friable.

  • 2.  RE: Terrazzo with asbestos in the matrix

    Posted 05-21-2020 05:03 PM
    If you aren't breaking up the tiles to remove them or install anything, you shouldn't have any issue just removing the wax and resealing.

    I had it in my garage in DC. Our general contractor did pull ours out *because* of the asbestos but in hindsight, I wish I had left in place. It was pretty cool. Of course, last year when we got a new sewer line put in, they had to jackhammer the garage floor, so I guess it was good it had been taken care of before that.

    Ronda Bernstein
    Historical Consultant
    Washington DC
    Facebook/Twitter/Instagram: @histpresinc
    Contact to visit the National Museum of African American History and Culture!


  • 3.  RE: Terrazzo with asbestos in the matrix

    Posted 05-22-2020 07:06 PM
    At the NJ State House Annex we restored Zenitherm, a material with a magnesium oxychloride matrix with wood fiber and mineral aggregate. It also contained asbestos, depending on when it was manufactured. As Ronda notes, if you are only stripping and resealing, and not releasing fibers, then it should be easy. If you need to make repairs, or cut or drill, the cutting and removals should be done under some kind of containment, and an encapsulant applied. The repairs can then be done, and re-sealing. At the Annex, the workers making the repairs and sealing the material wore Tyvek suits and carried air monitors. Once they could show no asbestos in the air, they were able to proceed without the suits.

    Anne Weber FAIA
    Mills + Schnoering Architects, LLC
    Princeton NJ


  • 4.  RE: Terrazzo with asbestos in the matrix

    Posted 05-22-2020 01:39 PM
    I'm curious what material in the mix has asbestos, and at what levels? is it at a hazardous level?

    I agree, as long as you leave it intact and don't break up the material to a particulate matter that could be ingested then you would not exposing any workers to hazardous materials.

    Stephanie Clarkson
    Project Architect
    university of idaho
    Moscow ID