Exterior Foundation Waterproofing Membranes | Basement Finishing

Water damage and leakage are horrible situations. The problem is exacerbated when the entire building structure has been completed, and later, you realize that you should have applied waterproofing or it needed to be adequately implemented. Still, you should not worry; the requirement for waterproofing and safeguarding of constructions has led to new inventions of polyurethane polymers called liquid membranes. Polyurethane waterproofing membranes are one of several types, each of which has benefits.

This blog explains exterior foundation waterproofing membranes, their various types, long-term advantages, and more. 

What are Exterior Foundation Waterproofing Membranes?

 An Exterior waterproofing membrane is a technique to prevent water from penetrating your home. The waterproof blockade is applied below the ground surface from outside the foundation. Many vendors use only solid sheets to prevent water from entering; however, those sheets create joints, which become weak over time and allow water into your home or buildings.

Shotcrete and concrete materials are also used for foundation waterproofing; however, as time passes, these cracks become visible, and water can easily pour in, leaving it a breeding ground for mosquitoes. It also produces water molds that pose a danger to health.

Using sheets for waterproofing can often lead to water leakage. Several types of waterproofing solutions are available on the market; however, using a polyurethane liquid membrane is best. It is a liquid; once applied, let it dry, providing a consistent coating impenetrable to water. It maintains the building aesthetically and structurally, with lifelong security and peace of mind without worrying about water leakage.

Different Types Of Foundation Waterproofing Solutions

Foundation waterproofing is vital for any structure, whether a home, a complex, or any other type of building. There are various types of waterproofing solutions available on the market. Please find them below:

1. Polymer-modified bitumen membrane

The most widely used waterproof material is Polymer-modified bitumen membrane. Its installation is simple, and its popularity is high. The polymers are modified by mixing them with asphalt emulsion. This material provides enough strength to withstand temperature fluctuations and high loads, making it highly durable and efficient for waterproofing. These polymers in modified bitumen sheet membranes provide extra resistance, due to which they can also be used at places that sustain high temperatures, in addition to inhibiting water from passing through the foundation.

2.       Self-adhesive modified bituminous membrane

It uses tackifiers, polymers, asphalt, and mineral stabilizers. It further amplifies the structure when used with polyester, fiberglass, or a combination. The self-adhesive layer is fortified with paper, which is removed during installation. It provides excellent water tightness and flexibility. It also provides high tensile strength and resistance to temperature and aging.

3.       Ethylene Propylene Diene Monomer (EPDM) membrane

It is a high-quality rubber material used in the construction industry for waterproofing, roofing, and sealing applications. The membrane is commonly used to provide a waterproof barrier. The installation is quick and easy, demonstrating high tensile and tear strength. It provides resistance to ultraviolet rays, intense heat, and acids. Ethylene Propylene Diene Monomer membrane is a phenomenal substitute for torch-on membranes.

1. Thermoplastic membrane:

It is a single ply roofing membrane that uses a mixture of ethylene-propylene, polypropylene, and often polyester as a catalyst. The thermoplastic polyolefin (TPO) sheets contain colorants, ultraviolet resisters, and other additives to achieve the required strength. The sheets of TPO are 6 to 12 feet wide with a varying thickness of 40 to 100 mils. Thermoplastic membranes are more inexpensive than other waterproofing solutions.

4.       Bituminous membrane

Bitumen, also known as asphalt or coal-tar pitch, is prepared with organic liquids that are heavily sticky and viscous, which makes it suitable for basement waterproofing. It is used in construction and is essential for waterproofing basements, roofs, bridges, below-ground constructions, and other structures. The main advantage of Bituminous membrane is that it prevents rusting, and its products are environmentally friendly. One of the negative aspects of the Bituminous membrane is its explosive nature.

1. Polyurethane Membrane

Various innovations have taken place in the construction industry for enhanced living standards. Polyurethane polymer membrane is one such highly acclaimed innovation in this industry. It is a liquid membrane used to reinforce the foundation’s waterproofing. It is one of the most preferred methods used in the construction sector. The adhesive properties of Polyurethane polymer membrane are above par, and it has the potential to seal the most cumbersome protrusions efficiently and for longer.

Uses of Polyurethane polymer membrane materials:

1.       The Waterproofing materials used in polyurethane are long-lasting and durable; they provide high resilience and performance. These materials are used in the foundation, roof, balconies, and other building parts.
2.     Polyurethane materials prevent dust coating and maintain the brightness of the construction’s surface, strength, and aesthetic beauty.
3.       Polyurethane based materials are also used in foundations that dampen due to puddles of water.
4.     Due to the versatile and robust nature of Polyurethane polymer membrane materials, they are also used to provide safety to water tanks as they provide resistance to rust and are also harmless to health.
5.       These materials can be applied to both internal and external foundations.

Properties of Polyurethane polymer membrane

1.       Polyurethane polymer membrane comes with an assurance of zero water penetration
2.       It is flexible and can bear the normal movement of buildings caused by earthquakes, distortion, etc.
3.       These are resistant to ultraviolet rays and adverse weather conditions
4.       It has high tensile strength and durability.

Waterproofing Procedure of Polyurethane Liquid Polymer Membrane:

Please find the step-by-step procedure for applying Polyurethane Liquid Polymer Membrane for waterproofing-

1. First, prepare the foundation by rigorously cleaning its surface with no dust, grease, moisture, or debris left on it.
2.       Now analyze the cracks, cut them in the V section, clean them gently, and apply polyurethane based filling paste in the ratio of 1:2.
3.       Now neutralized the substrate using acid to remove the alkalinity.
4.       In this step, apply a polyurethane coating to the surface and leave it for 8 to 10 hours allow them to dry completely
5.       Now, keeping in mind the design ratio, apply a few successive coatings of PU using a thin paintbrush
6.       The most important part of the above steps is that all the coatings mentioned above must be dried for at least 14 hours before another coating round.
7.       The polyurethane coating must be continued 150mm up the parapets and a minimum of 100 mm into rainwater pipes.
8.       In the final step, PU coating is showered with 300 microns of sand. 

Comparison of Foundation Waterproofing Membranes:

Choosing the right foundation waterproofing membrane protects your building from water damage and ensures longevity. Here’s a comparison of some commonly used options, including their strengths and weaknesses:

1. Polymer-modified bitumen membrane:

• Advantages: Easy to install, affordable, durable, good resistance to temperature fluctuations and high loads.
• Disadvantages: Requires skilled labor, joints can be weak points, susceptible to cracking and ultraviolet (UV) degradation, requires torch application which can be hazardous.

2. Self-adhesive modified bituminous membrane:

• Advantages: Easy to install without a torch, good water tightness and flexibility, high tensile strength and temperature resistance.
• Disadvantages: Similar to polymer-modified bitumen in terms of cracking and UV susceptibility, it is slightly more expensive.

3. Ethylene Propylene Diene Monomer (EPDM) membrane:

• Advantages: Quick and easy installation, high tensile and tear strength, resistance to UV rays, heat, and acids, environmentally friendly.
• Disadvantages: Requires specialized adhesives, susceptible to puncture damage, less durable than other options.

4. Thermoplastic membrane:

• Advantages: Affordable, lightweight, easy to install, good resistance to chemicals and punctures.
• Disadvantages: Not as durable as other options, susceptible to UV degradation and high temperatures, can be difficult to repair.

5. Bituminous membrane:

• Advantages: Highly resistant to rust, long lifespan, readily available, affordable.
• Disadvantages: Requires hot application, which can be hazardous, prone to cracking and brittleness, and environmentally unfriendly due to asphalt content.

6. Polyurethane liquid membrane:

• Advantages: Seamless application, excellent crack bridging ability, flexibility and adaptability to building movement, high tensile strength and durability, resistance to UV rays and harsh weather, can be applied to internal and external foundations.
• Disadvantages: Requires professional installation, is more expensive than some other options, and can be sensitive to moisture during application.

Polyurethane vs. Bitumen:

While both bitumen and polyurethane membranes offer effective waterproofing, polyurethane generally boasts several advantages:

• Seamless application: Polyurethane forms a seamless coat, eliminating weak points like joints found in sheet membranes.
• Superior crack bridging: Polyurethane can flex and bridge over existing cracks, preventing water infiltration.
• Durability: Polyurethane membranes have a longer lifespan and are less prone to cracking and brittleness than bitumen.
• Application versatility: Polyurethane can be applied to various surfaces and in any weather conditions, while bitumen requires specific temperature ranges and hot application.

However, the higher cost of polyurethane is a factor to consider. Ultimately, the best choice depends on your budget, project requirements, and desired level of durability.

Remember: Choosing the right foundation waterproofing membrane is an investment in your building’s health and longevity. 

Consult with a qualified contractor to discuss your specific needs and determine the most suitable option for your project.

Advantages of Exterior Foundation Waterproofing Membranes

1.       It stops the seeping of water. A structure without adequate waterproofing has a high chance of foundational issues. Installing proper waterproofing solutions is important.
2.       Protects buildings:  Waterproofing methods Keep the moisture out and never let water in; otherwise, it can wreak havoc on your building’s structure. If left unnoticed, excess water can compromise the strength of the building, making it a risky place to live.
3.       Preclude Health Issues: Mold and mildew can easily grow if the structure is filled with water, and their exposure can lead to various health issues ranging from skin problems, asthma attacks, headaches, and respiratory disorders. Effective foundation waterproofing membrane techniques will ensure your and your family’s safety.
4.       Less maintenance costs: The prime benefits of using Exterior Foundation Waterproofing Membranes are their low cost and their post-installation service, which is also pocket-friendly.
5.       Rise in property value: Without waterproofing, the property’s resale endures pain, and you won’t get the expected returns. However, Suppose the exterior foundation waterproofing is installed adequately. In that case, it increases the property’s market value and gives you outrageous returns, as it is the most important part of the building to take care of.

Application of Exterior Foundation Waterproofing Membranes:

Exterior waterproofing is a crucial component in protecting the structure. It makes sure that buildings are usable from generation to generation. Exterior foundation waterproofing membranes are used in many applications, including walls, building decks, basements, roofing, parking areas, water tanks, tunnels, linings, etc. Please visit here to learn more.

Precautions To Keep While Exterior Foundation Waterproofing

Always follow the best practices as mentioned below while Exterior Foundation Waterproofing:

1.       Flammable substance: Keeping the products away from each other is best due to its highly explosive nature.
2.       Skin and Health problems: Always protect your body while working with waterproofing solutions. This chemical contains hazardous substances that can cause various skin and health problems.
3.       Wearing proper clothing: Waterproofing chemicals are dangerous, so it is essential to keep your safety kits handy and always wear gloves while at work. Always wear eye protection glasses or goggles while working with liquids.

Things to keep in mind while installing Exterior Foundation Waterproofing Membranes:

1. Waterproofing materials based on Bitumen become malleable in the scorching heat of summer because of their black color. It has a shorter life cycle due to the evaporation of the solvent.
2. Waterproofing based on cement is not durable, and cracks are visible over time, which results in leakage.
3. The protective layer of PU slows down the breathing potential of concrete.

For more details on Basement waterproofing, please click here

Exterior waterproof paint

Once the waterproofing and other construction work is completed, you and others will first notice the beautification of the building and its foundation, which is achievable using paint. Waterproofing paint provides additional protection between water and the exterior foundation, staving off moisture seeping through the walls. Exterior foundation paint delivers dirt-resistant and smooth finishing. It also gives an elegant look to your structure and the entire building.

Conclusion:

Waterproofing can be done at the initial stage of the foundation of the building, or it can also be installed once the structure is completed. However, if you notice any damage caused by excess water after the completion of the building, the cost of installing exterior waterproofing is high. Not to mention, prevention is better than cure. The best way to secure your building due to water damage is to apply the waterproofing coating at the initial stage of the building’s construction without further ado. This will minimize the cost, but you can also install and modify the foundation waterproofing at your own pace and according to your requirements.

Waterproofing is a methodology to prevent water and construction damage to a building or its features. Although many of us ignore the importance of exterior foundation waterproofing membranes and consider it an expensive task, Besides providing a water barrier, the right waterproofing also minimizes the cost of future maintenance or building facelift work.

FAQ:

Q: What is the best exterior waterproofing membrane?

A: Unfortunately, there’s no “one-size-fits-all” answer! The best membrane depends on factors like budget, foundation type, climate, and application. Popular options include:

• Bituminous: Affordable, durable, good for flat roofs and foundations. Can be brittle in cold temperatures.
• PVC: Highly durable, long lifespan, fire-resistant, good for roofs and balconies. More expensive than asphalt.
• TPO: Similar to PVC but more reflective, reducing cooling costs. May require specialized installation.
• Polyurethane: Seamless, crack-filling, penetrates concrete, but more expensive and requires professional installation.

Q: How do you waterproof a foundation from the outside?

A: Several methods exist, but common approaches include:

• Membrane application: Applying a pre-fabricated membrane like those mentioned above directly to the foundation wall.
• Liquid waterproofing: Coating the wall with a liquid sealant like polyurethane, forming a seamless barrier.
• Drainage systems: Installing French drains and gravel around the foundation to divert water away.

Q: What is the best waterproofing for foundation?

A: Again, it depends! Consider:

• For below-grade walls: Liquid polyurethane or cementitious coatings offer excellent adhesion and crack-bridging.
• For above-grade walls: Bituminous or PVC membranes are cost-effective and durable.
• For high water pressure: Polyurethane liquid membranes provide superior water resistance.

Q: What is the membrane on the outside of a foundation wall?

A: It could be a pre-applied waterproofing membrane, like asphalt or PVC, or a drainage membrane used in conjunction with a drainage system.

Q: Should I waterproof the outside of my foundation?

A: Waterproofing is crucial in areas with high water tables, heavy rainfall, or poor drainage. It protects your foundation from water damage, preventing cracks, leaks, and mold growth.

Q: How do you waterproof the outside foundation of a home to prevent water seeping into the inside foundation wall?

A: The methods listed earlier (membrane application, liquid waterproofing, drainage systems) can all effectively achieve this. Consult a professional to determine the best option for your situation.

Q: What is the longest lasting waterproofing membrane?

A: Thermoplastic membranes like TPO can last up to 60 years, while PVC offers a lifespan of 40-50 years. Bituminous membranes typically last 20-30 years.

Q: How long does exterior waterproofing last?

A: Lifespan depends on the material, installation quality, and environmental factors. Generally, expect 15-20 years for bituminous membranes, 20-30 years for PVC, and 40-60 years for high-quality thermoplastics.

Q: What is the best waterproofing for concrete foundation?

A: Polyurethane liquid membranes excel in adhering to and penetrating concrete, offering superior crack-bridging and water resistance. Cementitious coatings are another good option for concrete due to their compatibility and breathability.

Q: What are the disadvantages of waterproofing membranes?

A: Some drawbacks include:

• Cost: High-performance membranes can be expensive.
• Installation complexity: Some membranes require specialized skills or equipment.
• Maintenance: Regular inspections and potential repairs may be necessary.

Q: What is the strongest waterproofing?

A: Polyurethane liquid membranes boast exceptional strength and adhesion, effectively filling cracks and resisting water pressure.

Q: What is the cheapest method of waterproofing?

A: Applying asphalt coatings is generally the most affordable option. However, consider the long-term cost-effectiveness, as cheaper materials may require more frequent maintenance or replacement.