What do a swimming pool and commercial kitchen have in common? A lot more than you would think. As any restaurant owner will tell you, the one place that is never dry is the floor of a commercial kitchen. Everyday occurrences include slick floors resulting from overflowing pots and pans, power washers and liquid cleaning products. Although these scenarios can spell disaster, the right flooring and waterproofing systems can prevent leak damage as well as damage to a restaurant owner’s bottom line.

First things first: Not all waterproofing and flooring systems are created equal. Unsuitable waterproofing systems can bring about everything from mold growth and property damage to ensuing lawsuits and to health department citations. Also, for establishments located above operational businesses, owners must be prepared to prevent water damage to their own spaces as well as the mechanical and electrical systems below.

To ensure that the right waterproofing system is in use, it is imperative that owners have a realistic and accurate view of how flooring and waterproofing systems are developed and installed. Although it may seem like a hefty investment, selecting the correct waterproofing and flooring systems will reduce the stress and costs of future water damage complications. Materials and practices range from robust systems that can last longer than the average kitchen lifespan of 10 years to moderate systems that can potentially require repairs after two to three years and simplistic systems that will need repair in less than a year. 

Overall, more robust systems are recommended because on average they require less repair costs and cause less hassle and trouble for the owner. If a system has issues such as a crack or leak, the whole floor needs to be replaced, which means millions of dollars’ worth of kitchen equipment will need to be moved and the restaurant will have to be shut down—leading to lost revenue on top of added repair costs. 

Technical Specifications 

In order to make the appropriate selection, it’s crucial for owners to understand how flooring and waterproofing systems are built. Moving from the surface down, heavy duty systems (those tolerant of hot and caustic liquids) include a layer of tile and grout, then a pitched mud or thickset (with a 1.5” minimum thickness). The porous mud level promotes moisture migration towards the floor drains, floor sinks and stainless steel trough drains, and serves as a relief point for any kitchen liquid that migrates below the finished floor surface. Correct drain perimeters all have weep holes, enabling these liquids to flow into the various floor sink and drain bodies.

The slab is not the only area that must be waterproofed to avoid deterioration or moisture damage. Since the kitchen floor is the one place that is never dry, you want to treat it like a swimming pool. There’s been great success using a membrane system that was created for pools, deck coating and other exposed exterior applications modified for use in kitchen construction. As water inevitably gets splashed around during cooking or cleaning, it seeps into the walls and finds its way into electrical outlets and equipment connections. That’s why it’s crucial to apply the waterproofing membrane a minimum of 12 inches up the wall. A cement board is also strongly recommended for the bottom 18 inches of the walls in place of any moisture-resistant gypsum board to avoid water penetration into the wall cavity. Every floor and in-wall penetration should be sleeved and waterproofed because all kitchen floors flex due to hot water exposure, which allows liquid to penetrate openings. The result? Moisture builds up and then potentially finds a point of discharge, resulting in a huge leak.  

Better Safe Than Sorry

For those restaurants whose kitchens are located above sensitive facilities, a secondary waterproofing system can be installed to provide restaurant owners with absolute confidence that leakage will not occur. High-end malls often mandate back-up waterproofing systems in restaurants’ lease agreements. A more bulletproof back-up system requires, in addition to the waterproofing materials, placement of pans under every drain penetration. To install a custom back-up waterproofing system, it’s necessary to carefully coordinate the planning and design of the systems between the mechanical trades and the craftsmen installing concrete, waterproofing, and flooring systems. Local codes will also need to be reviewed for any possible limitations.

Health departments have no tolerance for standing water, nor should they. Inspectors have been known to dump a bucket of water under equipment and wait to see if the water drains — one of the reasons pitching is so crucial to your flooring system. Food waste and liquids accumulate throughout daily operations, requiring that floors are designed to properly drain. Floors should be sloped down towards the drain and you should ensure that the drains are properly installed, as they are fundamental to the entire waterproofing system.

After any complete waterproofing system is installed, it is invaluable to have a witnessed two-to-four-hour flood test where the drains are temporarily plugged and the floor is flooded with two-to-four inches of water. Mall managers, engineers, and clerks of the works should be present to witness the success of the flood testing, because most leases have language clauses pertaining to flood tests and/or properly installed waterproofing systems. Most often, these flood tests are reserved for elevated, second, or third level spaces, rather than slab on grade conditions. A final issue to keep in mind is that certain waterproofing systems have abnormally long cure times before any flood testing can be undertaken. As a result, schedule often plays an important part in the waterproofing system selection process.

With the appropriate waterproofing, tile and mud-job or epoxy system, restaurant owners can ensure that both their floors and bottom lines are protected. 

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