Underground Garage Drainage Membrane
Underground garages are convenient, but they can become a nuisance when they flood. This can cause damage, create slipping hazards and depress property values.
Effective waterproofing can prevent this from happening. Waterproofing membranes can stop water, contaminants and debris from infiltrating below-grade walls, which helps maintain structural integrity, lower repair costs, and save money on utilities.
Choosing the right product
If your garage is built on a concrete slab, you need a waterproof membrane to stop water and vapor from seeping through the concrete into your home or business. It’s best to use a membrane with an adhesive bond so that the membrane is fused with the concrete, offering superior protection. In addition to stopping water, some membranes like PREPRUFE Plus can also protect against aggressive soils, radon, and methane.
Leaks in an underground garage can be a real pain for occupants, from causing damage to vehicles or ruining the finish on interior surfaces. They can also be hazardous by causing slips and falls on the slippery wet floor. In some cases, the leaks can raise questions about the integrity of the garage structure itself.
To avoid these problems, your builder should have installed a perforated drain pipe Underground garage drainage membrane along the back of your garage and extended it down to a minimum of 4 inches below the final grade in your garden. The pipe should then be covered with washed rounded gravel the size of golf balls or walnuts. As the rainwater passes through the soil, it will discover this layer of gravel and drop down into it, exiting to daylight and never entering your garage.
Another product that can be used to prevent leaks is a tanking slurry. This is a specially formulated mixture that stops water from entering the structure, and it can be used as an independent system or combined with a waterproofing membrane to provide optimum protection. It comes either pre-mixed or in a powder form to be mixed on site with clean water. Tanking slurry is made from Portland cements, aggregates, chemical modifiers and an acrylic polymer that work together to block the passage of water into your garage.
Preparation
Water infiltration in parking garages is a major cause of concrete deterioration and steel corrosion. To prevent these problems, waterproofing measures are crucial in directing water away from the structural elements and preventing them from absorbing moisture.
The underground garage drainage membrane can be installed before or during construction. It can also be used in areas where soil retention is not a problem such as with mud slabs, carton forms or fine crushed beds/pea gravel. The membrane protects against moisture intrusion, methane and radon gas as well as providing superior crack-bridging properties.
Often the garage drainage membrane is placed over the top of the structural slab and then covered with a wearing course or cement screed. This wear layer provides an aesthetic finish and helps to prevent abrasion of the waterproofing membrane. The screed can also act as a thermal insulation, protecting the underlying structure from heat build up.
If significant water leaks are a problem, it may be necessary to install a crack injection system. This involves drilling small diameter holes into the concrete walls and inserting injection “ports”. Epoxy or urethane is injected into the ports to fill voids and seal pathways for water infiltration. This type of repair is usually performed by specialized contractors. When performed correctly, this method of crack injection can be a very effective way to repair leaking garage walls and floors.
Installation
The waterproofing membrane is typically installed before the concrete slab is poured, so there’s little maintenance required once it’s in place. However, it’s Geomat for construction important to perform regular inspections to locate any breaches in the membrane and repair them as needed.
This will prevent the infiltration of water into the garage and reduce the potential for mold and mildew to grow, which can create a health risk for anyone entering or working inside the building. In addition, the infiltration of water into the basement can lead to structural damage if the problem is left untreated.
To ensure the longevity of the waterproofing membrane, it is important to use a high-quality, long-lasting product. The installer should also follow the manufacturer’s installation instructions and best practices to minimize damage during installation. A professional installer should also be able to identify and correct any issues that may arise during the installation process.
For example, in cases of severe capillary moisture penetration through garage walls, the installer should be able to correct the issue by injecting the areas where the moisture is manifesting. This is a relatively simple repair but it’s important to note that it does not address the deficiency in the structure that allowed groundwater to reach the back side of the wall. In many cases, this type of repair only halts the migration of moisture and it will likely find another route into the garage through a different crack, cold joint or tie back.
Maintenance
The integrity of below-grade parking garages is critical for the safety and functionality of the structure. Poor drainage leads to water ponding, increasing slip-and-fall risks for facility users and speeding up concrete deterioration. Managing these risks requires effective drainage and regular maintenance inspections of the underground garage drainage membrane.
When a garage’s walls show water staining or efflorescence and no active leakage is present, this moisture is likely the result of construction infiltration during building construction and not an indication of ongoing leaks. In such cases, a professional cleaning will be required to eradicate the staining and efflorescence.
Hydrophobic treatment of the pit, located in the floor or foundation of the garage and intended for the collection of water, will also be necessary. This will ensure that the pit is not flooded and prevent fungus or mold from forming in the pit.
Lastly, the tanking slurry, or cementitious tanking product, PermaSEAL, will be required to stop water ingress and protect the underground garage. PermaSEAL is a highly advanced mixture of Portland cements, aggregates, chemical modifiers and acrylic polymer that can stop water ingress in the most severe conditions. It is available pre-mixed or as a powder to be mixed on site with clean water. It can be applied as a coating to the entire underground garage or to short wall segments that need protection.