Measuring vapor emission in stone and tile flooring installations

摘要

Ask any seasoned tile setter why a tile installation fails, and you will get answers ranging from poor setting techniques to defective materials or tile. Unfortunately, failures are not always caused by the setting method, the materials or the tile. A growing concern with failures is the substrate that the tile is placed over. Over the past several years, I have observed numerous tile and stone floor failures due to excessive vapor emission through concrete slabs. It amazes me how many installations are started without a very important step. That step is the vapor emission test. What is this test? Why is it important? What is vapor emission? A normal concrete slab will emit some degree of moisture as a vapor (gas). This is normal and expected. Vapor will always seek a warmer environment. The concrete slab is a cool environment, and vapor will be driven by capillary action to the warmer atmosphere. In this case, the warmer atmosphere is the inside of the building. The average amount of vapor emitted from the average concrete slab is 3.0 to 4.0 pounds of vapor per 1,000 square feet in a 24-hour period. If vapor emission exceeds 5.0 pounds, tile and stone should not be installed without taken precautionary measures.