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Exterior and Interior Waterproofing and Drainage - New and Existing Structures

Exterior and Interior methods of waterproofing walls, crack repair and stabilization, and crawl space waterproofing, have advanced considerably. Apex Waterproofing uses the latest, most advanced and proven systems and products available today. We are capable of completely waterproofing the basement envelope / environment, stopping water from getting in, from both sides - negative and positive (interior and exterior). Yes, according to Iowa State University, "basements are not designed to be waterproof", because contractors do not have the experience, nor do they want to increase their costs. At Apex, we do know how to design and waterproof a basement.

1.    Exterior or Positive side applications - Waterproofing materials like epoxy, polyurethanes, waterproofing cement, tar, rubber, pre-molded membranes, drainage mats, etc.,  are used to waterproof and vapor seal the walls before water can penetrate through to the inside. (Your builder actually had to do this to pass inspection to sell the home.) Proper installation of perimeter drain tile in gravel, alongside the footing, always below the floor slab level, should take care of drainage issues.

With existing structures, Exterior / Positive Side methods require excavation, sometimes down to the bottom or next to the foundation or footing (often called footer). Exterior methods of waterproofing can be very effective but are usually more expensive, sometimes prohibitive depending on the application, the company, and other factors. However, sometimes you have no choice. When structural issues are in evidence, outside excavation and repair may be the only solution recommended by an engineer (engineer's report), necessary for a permit, and to be approved by a city, county, or municipal inspector.

2.    Interior or negative side applications - Here, we are allowing the water to penetrate to a certain extent, and managing or stopping its direction or flow. Water, which enters at the cove, can be diverted to a sub-floor drainage system, which is New Residential Code in Maryland and Virginia (See Causes and Solutions). At the end of this drainage system is a sump pump or two, which discharges the water outside and away from the home. However, if water is coming through the wall, the fix is not so simple - a wall system has to be devised to manage that specific flow. When properly installed, the sub-floor, interior system may be just as effective or more so than exterior drain systems, often at a fraction of the cost. Sometimes, not!

Interior Drain Tile and Water Management Systems are commonly recommended to address water, which seeps through the cove (where the floor and wall meet) or through floor cracks. The procedure involves removing a portion of the floor along the perimeter foundation wall(s) about 12" to 20", digging a wide and graded trench, down to the bottom of the footing, laying round washed gravel, installing nothing less than 4" A.D.S. perforated drain pipe, which is then surrounded with washed gravel at the base of the wall.

On Concrete Block walls, we then drill weep holes to bleed the hollow cores, at every core and mortar seam. (See Video) Then, we run a wall drainage mat, Miradrain® 2000R over the weep holes, which allows the walls to continuously drain, covering the stone with a vapor barrier, and finish up with a Portland cement finish. The drainpipe (also called drain tile See History of Basements) either drains to daylight, or into sump containers, with Zoeller Commercial Grade, Cast Iron Sump Pumps to discharge the water up, and outside the basement.

We are basement waterproofing experts in Northern Virginia, including Alexandria, Arlington, Annandale, Mclean, Great Falls, Springfield, Fairfax, Maryland and Washington DC.

Be sure, be safe, Call Apex Today! (800) 656-4604.

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