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Interior Drainage Systems and Exterior Waterproofing


Many homeowners are completely uninformed on the differences between interior and exterior basement waterproofing or drainage systems. If you too are unsure which option best suits your home, this should explain these two options and hopefully make your process bit easier.

It is always important to do your research beforehand, but the best way to truly know which type of system will solve your problems is by contacting a professional such as ourselves.

We offer FREE INSPECTIONS and have the professional experience needed to ensure you receive the best solution.

Interior Waterproofing

Interior basement waterproofing is more often a remedial solution after water has already entered the home. Exterior waterproofing on the other hand, is more of a preventative method for keeping basements dry and protected. These internal systems are designed to direct water out of your home and away from the foundation. This involved digging a trough that collects water and directs it to a sump-pump, otherwise known as a French Drain.

Installing an interior French Drain around the perimeter of the foundation is most commonly done after the house has been built. This is because they are typically installed in response to a wet basement or sometimes, just before a basement finishing.

To install this kind of drain:
  • Perimeter of the basement floor removed reaching down to the footer
  • Concrete is removed along with a 2-inch gap around the edge to allow water in from the basement walls
  • Weeping holes, or drainage holes, are drilled every 12-18 inches to allow water to enter the trench
  • A layer of stone is laid down at the bottom of the trench
  • A 3 to 4-inch perforated drain pipe is laid on top of the stone and graded downwards towards the sump-pump
  • More stone is laid around and on top of the pipe to keep it in place and protected from surrounding dirt
  • Finally the pump is installed to remove the water from the house and drive it away from the foundation

This type of system is easy to install and easy to maintain. The sump-pump will need little annual maintenance to perform properly but this is the extent of it.

Additionally, in interior French Drain is much less likely to clog than an exterior, mostly due to the fact that it is not sitting underneath several feet of soil nor exposed to the elements.

Exterior Waterproofing

Exterior waterproofing is a bit more involved than interior. They are installed on the outside of your foundation to prevent water from ever entering your basement in the first place, rather than as a response to it.

This process requires excavating the soil around the home to expose the foundation so that a durable waterproofing sealant can be applied. The coating keeps the exterior foundation walls sealed off from any water in the surrounding soil. Although it is a bit more extensive than an interior system, this type of waterproofing is effective and preventative.

Here’s how it’s done:
  • First excavate the dirt around the foundation of the home down to the footer. This reaches approximately seven feet into the ground but varies depending on the home’s age and size
  • The wall is then cleaned and we apply a tar coating as an adhesive for the protective rubber membrane. These together prevent all moisture from migrating into the wall wherever applied
  • A drainage board is then placed over the membrane to protects the rubber from back-fill damage as dirt is placed back around the foundation
  • We then install an exterior drainage system, fastened to the wall with a 4-inch perforated pipe along the house footer
  • Before back-filling, we install a fabric is laid at the bottom of the trench and up the sides. The pipe is laid over it and stone is filled around the pipe to keep it in place and protected
  • Lastly, we place a crock-well that reaches the bottom of the footer and holds the pump. That pump drives the water away from the house, keeping the wall and interior space dry

Contact Us

If you are experiencing any signs of moisture in your basement, it’s best not to make it a DIY project. Contact a professional for any of your interior or exterior waterproofing needs!

Give Basement Solutions a call today at 610-495-9111 for a FREE INSPECTION. For more detailed information on services, please visit www.basements911.com today.