Waterproofing is a critical step in protecting a building from moisture damage. While you may be familiar with above-grade waterproofing, which protects areas above ground, below grade waterproofing is essential for any structure with sections below ground level, such as basements or underground decks.
If you are a contractor new to waterproofing, understanding the importance of below grade waterproofing is crucial. Basements and other below-ground spaces are particularly susceptible to moisture intrusion and flooding, which can lead to significant damage over time if not properly managed. Without effective waterproofing, these areas are prone to water infiltration, which can cause structural deterioration and costly repairs.
Common Applications for Below Grade Waterproofing
Below grade waterproofing is widely used beyond residential basements. It is an essential practice for protecting various structures and areas:
- Foundation Walls and Slabs-on-Grade: These are common in both residential and commercial construction and require protection from moisture to prevent structural damage.
- Plaza Decks and Green Roofs: Public buildings often feature these structures, which may be situated below ground level or on top of parking garages.
- Planters: In commercial and residential landscapes, below grade waterproofing helps maintain structural integrity.
- Sumps and Elevator Pits: These areas, especially during the construction phase, need waterproofing to avoid water accumulation and damage.
Regardless of the specific application, choosing the right waterproofing system is critical. There are three primary methods to consider: Positive Side, Negative Side, and Blind Side waterproofing.
Positive Side Waterproofing
Positive side waterproofing is applied to the exterior surface of a building, providing a first line of defense against water infiltration. This approach is often preferred because it allows for easy inspection and maintenance of the waterproofing membrane, ensuring long-term effectiveness. However, it requires access to the exterior face of the structure, which may not always be feasible.
Key considerations for positive side waterproofing include:
- Selecting high-quality waterproof materials suited to the project.
- Evaluating the need for insulation to enhance energy efficiency.
- Considering vapor barriers to control moisture transmission.
- Implementing drainage solutions to manage excess water effectively.
Negative Side Waterproofing
Negative side waterproofing involves applying a waterproofing system to the interior surfaces of a structure. This method is often used when exterior access is not possible. While it can provide adequate protection, it may not be as durable as positive side waterproofing because internal structural movement can cause cracking or damage over time, necessitating periodic maintenance.
Blind Side Waterproofing
Blind side waterproofing is typically used when there are space constraints or property line issues, making exterior access impossible. This method involves applying the waterproofing membrane to the underside of structural slabs before they are cast. It offers similar protection to positive side waterproofing but requires careful planning to ensure effective drainage and waterproofing integrity.
Drainage Systems for Below Grade Waterproofing
Effective drainage is a vital component of any below grade waterproofing system. Proper drainage ensures that water does not accumulate against the waterproofed surfaces, which could lead to seepage and damage. Common drainage solutions include:
- French Drains: Trenches filled with gravel and a perforated pipe that direct water away from the building.
- Under-Slab Drainage Systems: Designed to manage water under concrete slabs.
- Drainage Boards and Footing Drains: Installed along the foundation to channel water away from the building.
- Sump Pumps: Essential in flat areas where water naturally collects, these pumps help remove water from below-grade areas.
Contact Us for Expert Below Grade Waterproofing Solutions
For contractors new to waterproofing, selecting the right system and implementing it correctly is critical to the longevity and safety of any structure. At Pli-Dek, we specialize in providing high-quality below grade waterproofing solutions that are easy to apply and tailored to various structural needs. Contact us to learn more about how we can help protect your projects from moisture damage.
By focusing on the key considerations and benefits of below grade waterproofing, this guide aims to provide contractors with the knowledge needed to make informed decisions and ensure the success of their projects.