How to Select a High Quality Drainage Membrane
Drainage composites are a critical component of below-grade commercial foundation systems, but they’re often misunderstood and viewed as accessories. Understanding the true performance criteria that needs to be met is essential for selecting a drainage membrane.
This non-woven geotextile collects and transports water to drainage outlets, enhancing waterproofing. Its high compressive strength and durability make it resistant to impact and stress cracking.
PVC Waterproofing Membrane
PVC waterproofing membrane is an excellent choice for new and remedial construction projects. It is an economical option and is easy to install, making it a good choice for projects with limited timelines. Waterproofing prevents structural damage to a building and can save money by avoiding costly repairs and reducing the risk of health issues for the structure’s occupants. It also protects the building’s interior and exterior, increasing its value and improving resale potential. Waterproofing membranes are also environmentally friendly and can be recycled even after many years of use.
PVC sheet membranes provide dependable waterproofing protection that is effective for many years. They are designed to withstand harsh weather conditions, including strong winds and rains. They can be installed even on damp substrates, and their seams are hot air welded to ensure they stay sealed and protected. This waterproofing solution is better than liquid-applied materials, which require the services of specialized contractors and are susceptible to weather conditions during the installation process.
PVC membranes are flexible and work well in both freezing and warm climates. They can be used for a variety of applications, including balconies, walkways, plazas, garage floors, rooftop terraces, and green roofs. They also can be used in industrial and residential roofs, planter boxes, retaining walls, tunnels, reservoirs, and drinking water tanks. PVC membranes such as Wolfin Polyester/PVC also have an exceptional elongation attribute, allowing them to handle building movement without tearing or separating.
Geotextile Membrane
A geotextile membrane (also known as Terram) is a large sheet of protective fabric that’s used in ground and drainage projects to separate, filter, reinforce, drain and protect soil. Woven and non-woven types are available and both have a variety of benefits and uses, as well as different strengths.
A woven type of geotextile High quality drainage membrane membrane is made from synthetic fibres – polypropylene – that are needle punched together to create a tangled mat, or woven into tapes and woven into a large sheet. Woven geotextiles are heavier, thicker and stiffer than the non-woven options. They’re best suited for separation, reinforcement and protection projects.
On the other hand, a non-woven type of geotextile membrane is made of polypropylene fibres that are bonded together and then needle punched to create small holes throughout the fabric. This makes them much more permeable, so they’re better suited for drainage uses e.g. French drains and soakaways.
The filtration function of geotextiles allows water to pass through while trapping debris and soil particles. This helps keep drainage systems free of clogs and prevents contamination of sensitive water sources such as lakes, rivers and ponds.
A geotextile membrane also acts gabion mesh factory as an effective weed control fabric, as it prevents smaller weeds from filtering down into coarser materials and blocking up drainage pathways. This allows the plants that you want to grow to have room and not be competing for space or nutrient resources with those you don’t.
Perforated Dimple Membrane
Dimple membranes, also called sheet drains, are an excellent solution for a wide range of drainage applications. They typically consist of a high-density extruded polyethylene or polypropylene sheet that is molded into a series of raised knobs, or dimples. Many have a non-woven geotextile bonded to the dimple side that acts as a soil filter. The height, width and depth of the dimples as well as the compressive strength varies between manufacturers.
The primary benefit of these membranes is that they allow you to skip the need for gravel, which can lead to clogging, and provide superior flow rates. They can handle hydrostatic pressure far more effectively than perforated pipe, making them an ideal choice for basements. They can also be installed quickly, and are highly durable. According to Tom Fallon at Cosella, their expected lifespan is 50 years or more, and are likely to last longer than the building itself.
A number of manufacturers offer these products, including American Wick Drain’s Akwadrain, Tremco Barrier Solutions’ TremDrain, and Cosella Dorken’s Delta Drain. The latter offers a six-inch product that can handle 21 gallons per lineal foot under hydrostatic pressure, and has deeper dimples to prevent clogging. A similar product from Mar-Flex is able to support 100 gallons per minute under hydrostatic pressure. These products are typically installed in a concrete deck, with the dimples facing down, and over a layer of waterproofing membrane.
Dimple Mat
For a dimple membrane, look for one that’s made of thermoplastics like high-density polyethylene (HDPE), which provides strength and durability. It should be strong enough to withstand the backfill process, and it should also hold up well against moisture that gets behind foundation walls during construction.
Ideally, a good dimple mat will be perforated to promote drainage and help keep the basement dry. But, you can choose from non-perforated options as well, depending on the needs of your basement.
Air gap dimple membranes are a great choice for basement applications because they are designed to direct groundwater and construction moisture directly towards perimeter footing drains. In this way, the membrane helps to prevent moisture from causing basement leaks and mold issues in finished buildings.
As an added benefit, air gap membranes can also be used as a soil erosion control product. These membranes are typically installed on the top of a geotextile and provide a barrier that keeps water, soil, and chemically toxic water gasses from reaching and damaging finished building surfaces.
Another benefit of air gap membranes is that they are easy to install and can be mechanically fastened using fasteners provided by the manufacturer. For example, Armtec’s Platon Foundation Protector can be easily fastened with a nail gun or hammer, and installers can simply follow installation guidelines for optimum results. This can save time, money and hassle for the builder, while also avoiding the need for expensive spray equipment or health hazards associated with solvent-based products.
