Gypcrete - Good and Bad
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By Shawn Maciewicz, House of Floors, Inc.
As more and more apartment communities undergo the condo-conversion process or the rehabilitation to compete with available condos for rent, there have been excessive demands placed on upgraded flooring. One of those upgrade options includes changing existing sheet vinyl to ceramic tile.
In a Multi-Family application, there are several things that you must know before hiring a company to install ceramic tile on your property:
1) The Law- Federal and state lawmakers have written volume after volume of Fire Codes that pertain to multi-family dwellings. One of those codes specifically target what is called gypcrete or gypsum floors. The code is written to address the fire barrier between two separate dwellings. The existing flooring material or replacement flooring material must provide a one to two hour fire barrier according to code.
Gypcrete is most commonly used by manufacturers of construction industry materials to make a variety of subfloor products. Typically when building a multi-family building, the first floor units are built by pouring a 4" solid concrete slab. In order to save on costly building materials, the second floors will use what is often called an "acoustical" floor system. When using this type of system for building second and third floor units, the subfloor will have a plywood substrate then it will be covered by poured gypcrete, as it is less expensive than pouring a slab. The gypcrete will act as a stabile subfloor for carpet and will retain the fire barrier that the Fire Code requires. Gypcrete floors are not do-it-yourself projects; the manufacturers only permit installation by licensed applicators only.
2) The Cost- Gypcrete floors have great benefits to reducing costs during the construction phase, however host a multitude of problems later on in the life of the building. If your building was built using lightweight gypcrete on the second and third floors, then you will run into a few problems when trying to upgrade to ceramic tile. Firstly- re-pouring gypcrete can be very costly from a labor standpoint. Secondly- after time, gypcrete will start to crumble turning into a very fine dust-like particulate. Before you upgrade to ceramic tile, you will want to remove the existing flooring, whether that be vinyl or VCT, and during this process the gypcrete will start to crumble, and also come up in large chunks. This is where it is very important to follow the fire code. FIRE CODE says you MUST replace it using at equal or better material within the guidelines of the code. The material that you use must have a minimum of a 1-hour fire barrier, so you have a few options. Obviously your first option is to hire a subfloor expert to come and re-pour gypcrete in the damaged areas. This option tends to be very costly and time consuming. In addition we have found that in most cases even when gypcrete is re-poured correctly, and ceramic tile is installed directly over the new gypcrete, it does not take long for the gypcrete substrate to start to deteriorate. We have seen ceramic tiles start cracking and have a very hollow sound as quickly as 6 months after being installed. This result is from the gypcrete being compacted, or impacted by a hard floor such as ceramic and tends to break down into a dust underneath the tile which results in a hollow sound that will eventually lead to cracking tiles.
3) The Alternatives- Your second option is to use a cement board, commonly called backerboard or Hardi-board. This ¼" cement board is constructed of a cementious core sandwiched between two layers of fiber mesh. By using this type of product you can minimize your cost, eliminate unexpected delays and speed up the turnaround time needed to finish the upgrade. Once you have removed the existing vinyl or VCT, and the original gypcrete has either come lose or deteriorated, you can fill in the damaged areas with self leveling patch or mud, and then install your ¼" cement board. The labor associated with screwing down the cement board is far less than that of a certified technician for gypcrete and the cement board also complies with the 1-2 hour fire barrier required by law.