What is Better, Interior or Exterior Foundation Waterproofing?

Great Lakes Waterproofing specializes in exterior basement waterproofing, stopping water before it goes through your walls for Real Waterproofing.  Most waterproofers want to rip out part of your basement floor, install a drain-tile and pump the water back outside  

Using all-natural bentonite, blended for waterproofing, we inject the surrounding ground with a bentonite slurry that looks like chunky oatmeal. Depending on soil conditions, this can be a few gallons up to hundreds.  Filling voids and water pathways, bentonite is a highly effective all-natural matarial that gets a "excellent" rating from HUD as a basement waterproofing material.

Most ground surrounded buildings starts with a foot or two of hard-packed dirt, but under that we usually find much softer, less dense or even hollow ground, this is where water is collecting looking for any opening into your foundation.  Bentonite will find these voids and water pathways, stopping the flow of water on the outside.

Great Lakes Waterproofing can easily do large, long foundation walls, sealing up the walls from the outside, the same way the water moves through.

With this cost effective approach, we don't disturb customers, employees or students while working.

Over our 48 year history, we've worked on all kinds of large projects including tunnels, pump houses, factory buildings, school buildings, college buildings, hi-rise buildings, etc.

Stopping water outside of the foundation is Real Waterproofing, it helps slow down concrete degradation and mold and mildew growth.

Drain-tile for basement waterproofing has been around since the turn of the century but until the last 40 years, it was rarely used inside to help with wet basement issues.  Most homes and buildings are built on dry ground so it was unecessary to install drain-tile under the floor when the building was new.

Interior drain-tile waterproofing systems are now one of the most popular ways to manage water but they're not always the best solution.  For poured, stone or rubble walls they are not effective at stopping water that comes in above the floor straight through the basement wall.  For block walls they can work great but over time dirt and silt may clog inside the blocks, on top of that, they don't do anything to stop mold and mildew from growing on the wet blocks.

Exterior waterproofing work may include trenching the foundation down to the footings, this is EXTREMELY DANGEROUS and should only be done by professionals using trench-boxes made to OSHA Specifications.  TRENCH COLLAPSE IS THE NUMBER ONE KILLER OF BASEMENT WATERPROOFERS.  

The foundation should be cleaned, cracks repaired and products like a bentonite membrane should be installed on the foundation surface

We do not recommend backfilling with rocks, gravel or other porous materials, this area will collect a lot of water which may create much larger problems than before.  This water will expand and contract with a change in temperature, pushing it's way back into your basement.

Foundation cracks and holes are the #1 reason why basements get wet, this 1920 home has a vertical crack that goes all the way down to the footing.  In the Minneapolis, Saint Paul Metro Area, cracks like this are fairly normal, this is most likely from movement of the foundation, the corner sinks just a fraction of an inch and cracks develop.

With Great Lakes Exterior Basement Waterproofing, the crack is sealed up permanently, with interior drain-tile, the water still flows through the wall but is now picked up by the system (if your lucky) and pumped back outside.  Would you rather patch the hole on your boat or keep bailing out the water?

When the exterior isn't sealed the foundation can still deteriorate further with more freeze-thaw cycle that has a wedge effect on cracks and holes, over time the holes will become larger and much more water will migrate through.  Sometimes just a small area needs to be waterproofed but most drain tile installers will want to install a system for the entire basement perimeter, tearing out part of the floor and wallcoverings.

Drain tile gets it's name from the original drain pipe system used to move water away from foundations.  Years ago, the pipe was clay and made like tiles in an oven.  Over time new plastic materials have replace the original clay pipe.  This exterior clay drain tile system had 1/2" spacing between the 12" long pipe where water would collect and move through the system into the cities sanitary sewer.  

This system has been dug up and the clay tile exposed. During the 80's most cities made homes, businesses and this apartment building, close up the discharge side of the system which drained into the city septic system.  They didn't want the clean rainwater being treated at the treatment plant.

Limestone, stone and poured concrete  foundations are perfect for Great Lakes Waterproofing Exterior Real Waterproofing.  A chunky slurry of bentonite is pumped near the basement foundation, filling voids, following water pathways and filling cracks and holes, stopping water from moving through the foundation.

Other methods of basement waterproofing, especially interior systems, are usually not effective, the points of entry are normally above the floor.  The only way to stop this water is to build an interior wall system, made from plastic panels, and allow the water through the wall where it drains down into either a drain-tile or above floor channel before being pumped outside through the sump pump.

We do not recommend this type of system, allowing water through the walls also does not stop any continued damage to the concrete wall.  Mold and mildew love dark, damp areas, providing the perfect breeding ground.

One of the exterior waterproofing methods we've seen is attaching a rubber membrane on the basement foundation starting at grade and going down 3', the membrane is then rolled out towards the yard another 3'-4'.

This can be effective if the water is entering in this area of the wall, our experience is that cracks go from floor to ceiling and the membrane only covers a portion of the crack, water will work it's way around the membrane down to the softer ground under it and enter the crack.  We've worked on many homes that had this material installed and after a handful of years the water has found new pathways around the outer edge.  See how the area looks like it could hold water?  It does and it holds a lot, this water eventually wraps around the membrane back towards the foundation wall.  The soft porous dirt that was backfilled in this area will hold a ton of moisture.

This also requires a lot of work, a large amount of landscaping around the foundation must be removed to install the membrane.  This is Great Lakes Waterproofing's least favorite way to fix water issues.