Does my terrazzo floor need replaced after being subjected to a flood?


Hello, flood victim here in Houston. House flooded twice in less than 12 months. Have travertine tile on top of vapor barrier and below that terrazzo sub floor followed by another vapor barrier and then slab on grade throughout foyer, family room, and kitchen. Floors submerged in water twice over 12 months (1-3 feet of water in house). Adjuster finally gave us travertine removal but not terrazzo. Should terrazzo be removed for possible trapped moisture between slab and slip sheet leading to potential air quality problems and or potential bonding issues in the future?


ANSWER - I'm guessing that the terrazzo floor is the cementitious type and not the epoxy type, but either way, if the terrazzo floor was originally installed correctly, it should not have been harmed by the flood.

If you had a vapor barrier on top of the terrazzo then it may not have been saturated with water during the flooding. But even if it had, it should be able to dry out and it should not be necessary to replace it.

When you replace the travertine floor, remove the vapor barrier under it and let the terrazzo floor dry for a few days with fans and dehumidifiers.   You then can put down another vapor barrier over the terrazzo.  Use a grade D breathable vapor barrier cleavage membrane if you are going to install an wire reinforced mortar bed over it.  If you are going to bond directly to the Terrazzo, I would first scarify it to open up the pores and then apply a liquid applied waterproof membrane that meets ANSI A118.10 and A118.12.  This type of membrane is breathable and it is both a waterproof membrane and a crack isolation membrane.  Make sure you run the membrane up the walls at least as high as the water gets.  This way you can contain the water from future floods and limit the collateral damages.

If you are going to install a mortar bed over the terrazzo, then apply the waterproof membrane on top of the mortar bed and up the walls for preventing future damages from flooding.

7 thoughts on “Does my terrazzo floor need replaced after being subjected to a flood?

  1. Donato Pompo says:

    According to the IICRC (Institute of Inspection Cleaning and Restoration Certification) there are standards for the cleaning industry and for water damage restoration. IICRC’s S-500 standards provides three categories describing the type of liquid involved.
    Category 1 is liquid from a clean and sanitary source.
    Category 2 is liquid considered to be grey water.
    Category 3 is the worst classification and is grossly unsanitary and is called black water.

    Looking at your photos and your description I would assume you had a category 3 liquid. This probably justifies removing the travertine stones. The terrazzo should be fairly dense and might not have been saturated with the category 3 liquid.

    To verify if the terrazzo has been contaminated and to what degree, I would have an Industrial Hygienist evaluate the terrazzo. They should take samples from the surface of the terrazzo to test for contaminates, and they should take a spot on the terrazzo and grind it down to certain levels to see if the interior of the terrazzo was contaminated. This will determine if the terrazzo can be restored or if it needs replacing.

  2. Anne says:

    I am installing terrazzo on my flat roof. Do I need to waterproof the concrete slab below before i install the terrazo?

    • Donato Pompo says:

      All roof applications need waterproofing. Even if the existing concrete slab is waterproofed under it, I would still waterproof the top of the slab. Water damages is one of the greatest problems that cause costly repairs.

      Terrazzo systems offer waterproofing and crack isolation membranes. It would be best to go with a manufacturer of terrazzo systems and use their single source system that provides an extended warranty.

      Make sure when you waterproof the concrete slab that you run it up the perimeter walls at least 3 inches above the finish surface. Also make sure you have adequate slope to drain and adequate drains to control where the water goes. The surface of the waterproof membrane must be sloped to a drain and include weep holes for water to drain away.

  3. Juan says:

    I have Terrazo Floors in part of my house. My house flooded and I had to remove carpet, tile etc. Now I want to install new porcelain on my floors. Since the terrazo was only in the hall and kitchen area, there is about 1” difference with my new floors. Question, Can I remove the terrazo without damaging my slab? Do I need to put any type of moisture barrier before I install my new floors?

  4. Donato Pompo says:

    Assuming you have a typical concrete slab, you should be able to remove the terrazzo from it. If the terrazzo was installed well it might take a lot of work to chip it out with a power chipping hammer. Then you have to prepare the slab for the porcelain tile maybe by grinding it down if it got beat up from the removal. Even if the terrazzo comes up easy, you should scarify the concrete slab and make sure it is porous and clean.

    You should check the relative humidity of the concrete slab. You normally don’t want it more than 80% RH or so for ceramic/porcelain tile. If there is elevated moisture then you can put down a very robust epoxy coating vapor barrier or a waterproof/crack isolation membrane. Check with the manufacturer of the installation products to see what their requirements are.

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