Underground Garage Drainage Membrane

Underground garages are convenient but can turn into swimming pools when it rains heavily. A waterproofing membrane can help prevent these problems and keep your garage dry.

Waterproofing membranes are sprayed or rolled onto surfaces, creating a seamless, joint-free membrane. They can be used in many different construction projects.

Negative side and blindside membranes are applied prior to concrete construction. These membranes protect the negative side of the concrete and provide drainage to the concrete walls.

Rainwater Runoff

Rainwater leaking into basement garages is all too common a problem and it can be extremely problematic. Besides being unsightly, it also increases the moisture load within the walls, which can lead to rusting and other structural problems.

The key to managing this is to divert the water away from the walls. There are several ways to do this including using an underground garage drainage membrane. These products typically consist of a perforated pipe and a woven geotextile drain mat, which work to channel the water into the drain and away from the waterproofing.

Protective layers and drainage solutions are recommended in almost Underground garage drainage membrane all below-grade waterproofing projects. The protection layer prevents damage during backfill operations and the drainage layer manages the hydrostatic head pressure, prolonging the membrane life.

In the case of this particular project, Frontier used their dimple membrane with a bonded geotextile to help keep the fines from washing down into and clogging the drain. This is especially important in sandy soils where the fines would normally just wash down and clog the system.

Regardless of which type of membrane is chosen, it is critical to thoroughly inspect and document any areas of water infiltration into the basement garage wall during the waterproofing process. This includes visually examining and photographing the wall segments as well as using forensic tools such as infrared thermography and moisture mapping.

Flooding

If the garage floor turns into a swimming pool when it rains, the waterproofing membrane has likely been compromised. The first step is to consult with a forensic waterproofing consulting firm that employs a team of architects, engineers and construction professionals well versed in investigating these types of problems. These experts can determine the makeup of the concealed waterproofing assembly, assess the location, extent and frequency of water leakage, and then prescribe repairs by a qualified contractor.

Perforated drain sheets (sometimes referred to as air gap membranes) are made of a polypropylene or high-density polyethylene sheet molded into a series of raised knobs, or dimples. These are typically bonded to a non-woven geotextile. The resulting product offers a wide range of uses in landscaping, parking decks, green roofs and underground structures. When installed with the dimples facing downward, it allows excess moisture to fall through and channel into drains, reducing hydrostatic pressure that could otherwise pond water on a structure’s surface.

Geotextile membranes are also useful for preventing soil blockages in drains that can cause flooding and standing water. They are commonly used to line a soakaway or land drainage hole before the element is inserted, to prevent silt or debris from entering the system and blocking the flow of water. These products are also effective at sorting particles – larger ones remain on one side, medium ones can pass through the membrane and into the ground, while finer ones may stay on the surface.

Moisture

Waterproofing of an underground garage is important for avoiding flooding, the accumulation of condensation and mold and the destruction of metal products stored in the garage. In addition, hydrophobic treatment of the pit, located in the floor or foundation of a garage, ensures that the moisture accumulated there is not pumped out into the living area.

Spiked membrane (also known as profiled membrane) is a modern material that perfectly protects the underground floors of houses from steam and moisture and creates an excellent drainage system. In addition, the spiked geomembrane serves as a protective layer against mechanical damage to the layers of waterproofing and thermal insulation during free filling of soil.

Almost all below-grade waterproofing projects require either a protection layer Geomat for construction that protects the membrane from damage during backfill operations or a drainage solution that manages the water away from the membrane. These solutions help to reduce the hydrostatic head pressure that could damage the membrane and extend its service life.

The tanking process is ideal for addressing areas of dampness in a subterranean garage wall. The tanking product is applied to the substrate while it is still damp, and once the membrane has cured it will form a tough outside adhesive layer that offers superior protection against moisture intrusion, radon and methane. The tanking system is also suitable for use on the walls and floor of a basement or inspection pit.

Safety

Unless an underground garage is properly waterproofed, the concrete floor is subject to water leakage from faulty drains and sewer systems. Facility managers should make it a point to regularly inspect and clean the drainage system to prevent blockages and avoid flooding. This is particularly important when rainstorms are heavy.

Water staining and efflorescence from leaking walls are not only unsightly, but can create slipping hazards for building occupants. In the worst cases, they can also lead to structural damage of concrete walls.

For buildings with underground parking garages, it is essential to install a waterproofing membrane that can withstand the heaviest vehicles such as cars and trucks. It must be resistant to chemicals like gasoline, diesel fuel, alcohol, cleaning detergents and de-icing salt. It must also withstand mechanical shocks.

The ideal membrane for an underground garage is one that combines protective layers, drainage and waterstops. Protective layers can help prevent damage to the waterproofing membrane from backfill or consecutive trades. They can also provide added insulation and strength to the membrane. Drainage membranes, on the other hand, help manage the flow of moisture and ensure that it is channeled to the correct drainage points. Finally, waterstops can help seal joints and reduce the risk of leakage. This is especially important for parking garages that are frequently occupied with commercial/office vehicles and warehouse type vehicles such as carts, pallet jacks or forklifts.