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Installing Interlocking Plastic Subfloor to Prevent Basement Water Damage

Bob talks with Larry Janesky of Basement Systems Inc., about the equipment being put in place to prevent moisture damage. An underlayment is being put on the floor to prevent water transfer. The underlayment is a plastic intelocking subfloor made specifically for basements. Organic material, like wood, should not come into contact with the concrete subfloor because water vapor rises up through the concrete and can create problems with mold. Traditionally, people remodel basements by putting visqueen down on the concrete, laying down pressure-treated 2x4's, insulating in between the boards, and then laying down a plywood subfloor. The ThermalDry inorganic underlayment is a better solution as it has tracks to allow some air circulation. With a traditional subfloor, water vapor condenses into water underneath the visqueen then transfers to the wood and organic materials in the subfloor, causing mold and rot. Plumbing leaks can also result in a wet subfloor, causing the plywood to buckle and mold to grow. ThermalDry underlayment is quick to install, which saves time and money. The panels lock together with teeth and a shiplap design to stop the water vapor. The tiles allow for a little expansion and contraction and take up only a half-inch of the basement's ceiling height. This underlayment system costs about the same amount as the traditional method but, unlike traditional subfloors, does not require replacement after a water episode. If there is a water problem, the tiles can be lifted up, dried, and put back in place once the water issue is addressed. On a flat floor, the tiles will lay flat and the perimeter tiles will be secured to the floor. The completed floor will be made up of three layers: the underlayment, the pad, and the carpet. These multiple layers will minimize any sound from the rigid plastic coming into contact with the concrete slab. The Melrose home has a wavy basement floor, so extra fasteners will be put in to hold the underlayment down. A dehumidification system will be put in the basement to draw water out of the air before it becomes a problem. It's important to use a dehumidifier designed specifically for basements as most dehumidifiers are rated for 80 degree temperatures and basements typically are much cooler than this. In this project, the dehumidifier installed was a SaniDry Basement Air System which has air filtration built in and is Energy Star rated. More information