The Role of Foundation Drainage Systems in Interior and Exterior Waterproofing
When we consider all of the frustrating challenges Mother Nature presents to homeowners, one of the most consistent problems is water. A substantial amount of time, money and ingenuity goes into keeping water away from everywhere we don’t want it. Waterproofing is a crucial aspect of home maintenance, especially in geographical areas prone to heavy rainfall or high groundwater levels. There are two primary methods used – interior and exterior. Each serves a unique purpose and has distinctive differences.
Interior Waterproofing:
Interior waterproofing involves addressing water infiltration issues from within your home. It is typically applied to the interior walls and basement areas and becomes necessary as a result of being unable to properly waterproof the home’s exterior due to grade, obstructions, etc.
Water Diversion: This method primarily focuses on managing and redirecting water that has already penetrated the foundation or walls. It uses systems – such as interior drainage channels, sump pumps, and vapor barriers – to channel water away from your basement and/or crawl space.
Moisture Management: This helps control humidity levels within your home, improving indoor air quality and reducing the risk of mold and mildew growth.
Pros: Interior waterproofing is relatively less invasive and can be done without extensive excavation work. This often makes it a preferred choice for existing homes with limited external access. It is generally less expensive and often comes with a lifetime warranty.
Cons: If water has already entered the foundation, the footer can still sit in wet earth. Of course, this is not a good thing.
Exterior Waterproofing:
This is always the preferred choice but is not always feasible on existing homes. Waterproofing is applied to the outside of the home’s foundation walls, typically during construction. Unfortunately, it’s virtually impossible to fully reach the exterior foundation of most existing homes due to porches, patios, driveways, etc.
Preventative Measure: This method is proactive and aims to prevent water from reaching the foundation walls. It is done during the construction phase or requires excavation to expose the existing foundation. Once the foundation is exposed, waterproof membranes (typically made of rubberized asphalt or bituminous materials) are applied along with drainage systems and appropriate sealants.
Pros: Exterior waterproofing provides a robust defense against various water sources, such as rain, groundwater, and melting snow. It offers long-term protection and can extend the lifespan of your foundation. By keeping water away from the foundation, exterior waterproofing helps prevent structural damage, including cracks and weakening of the foundation walls.
Cons: While exterior waterproofing offers superior protection, it tends to be considerably more expensive and disruptive than interior methods. It is typically only considered during major renovations or new construction projects.
Drainage Systems:
Foundation drains are a critical component of both interior and exterior waterproofing systems. These pipe systems collect and redirect water away from your home, working together to protect your foundation from water damage. The following are key types of foundation drains:
French Drain: A French drain system consists of a trench filled with gravel and a perforated PVC pipe. This design allows water to flow away from problem areas toward a sump pump or, by way of gravity, to its intended destination. Learn more about French drains on our blog.
Sump Pump: Sump pumps detect rising water levels within the sump basin and pump out water through a discharge pipe. These can be installed in basements or crawl spaces. Read more about how sump pumps work on our blog.
Footing Drainage: This system involves a perforated pipe installed alongside the foundation footings, directing water away from the foundation to prevent pooling and damage.
Grading Drainage: This method ensures the land around your home is sloped to naturally move water away from the foundation, preventing water from collecting near your home.
Choosing the Right Method:
The choice between interior and exterior waterproofing depends on several factors, including your budget, the age of your home, and the severity of water infiltration. In some cases, a combination of both methods may be necessary for optimal protection. We recommend getting an honest evaluation from a contractor experienced in both methods. You’ll want to have an in-depth conversation about the pros and cons of each.
Buyer Beware:
Beware of companies that only offer a single solution, such as painting walls, without addressing the root cause of the issue. Contractors who focus solely on selling their services rather than providing the best solution for the homeowner’s needs, can be misleading.
Unfortunately, we see this happen all too often. A reputable company should recommend alternative solutions or refer you to another expert if the required work is outside their scope of services. Always ensure you are working with a licensed, reputable contractor with solid references to avoid unnecessary headaches and provide the best results for your home.
Both interior and exterior waterproofing methods play vital roles in safeguarding your home against water damage. Understanding their differences can help you make an informed decision to ensure your property's longevity and structural integrity. Consulting with a professional waterproofing contractor is your best bet to determine the most appropriate solution for your specific needs. Please let us know if we can help.