Exterior basement waterproofing or interior basement waterproofing?

Exterior basement waterproofing or interior basement waterproofing?

So many people want to know if they should choose exterior basement waterproofing or interior basement waterproofing to stop their basement water seepage.  Some people want to know what solution will truly fix their problem where others just want the cheapest solution that will give them dry space.  And of course there are those who fall anywhere in between.  Let’s review the differences and what each solution accomplishes to help answer the question: Exterior basement waterproofing or interior basement waterproofing?

exterior basement waterproofing or interior basement waterproofing?
water entering basement walls through the soil=seal failure

If you have wet basement walls, or just damp basement walls that you have to scrape and paint more often than every five years to keep it looking decent then obviously water is getting into your basement foundation walls.  The best “fix” to solve the problem is to stop the water from getting into the foundation walls with exterior basement waterproofing.

The process of exterior basement waterproofing involves excavating down to the bottom of the foundation.  Then the walls are cleaned of debris etc… to prepare for application of a waterproof coating.  All cracks and gaps are filled in and a waterproof coating is brushed, rolled or sprayed on to the foundation sealing up the porous surface. Then a waterproof membrane is applied to completely waterproof the foundation.  At Pioneer we apply a dimpled membrane which gives added benefits of air gap technology and a bit of cushion against the soil pressure.

New foundation drainage is installed.  This step is as critical as the sealing of the foundation.  The new foundation drainage should be 4″ PVC perforated pipe and it should have a pitch, or downhill slope, towards the evacuation point.  The evacuation point is either a sump pump system or a gravity drain that either exits the surface somewhere away from the foundation, or ties to a city drainage system. Many contractors do not ensure proper flow of the drains away from the foundation because most municipalities do not require it.  I know that sounds crazy and it is.  This problem of drains not flowing properly is very prevalent in new construction.

After drainage is installed properly a back fill of gravel is installed over the foundation drains.  Top soil is then installed over the gravel with a positive slope away from the foundation.

If your basement walls are in good shape other than the bottom and you are getting seepage coming from the wall floor seam under heavy rain events an interior basement waterproofing system will give you a dry basement.  But the question is what will actually fix the problem, exterior basement waterproofing or interior basement waterproofing?  If the seepage is due to your exterior foundation drains failing, then replacing them on the outside will put you back to like new.  However, if you see signs of water under your basement floor, like floor cracks that are discolored or white powder on the floor in areas…or even actual water seepage from weak points in the floor itself, an interior basement waterproofing system is the only way to truly fix your problem.  We see people who have this problem and have hired other contractors to excavate their basement and waterproof from the outside only to continue leaking.  The reason is ground water build up under a foundation will get trapped under your floor and not make it to the outside drainage.

water under basement floor
white powder build up around floor cracks = water under the floor

Ground water problems usually show only after sustained periods of rain or fast heavy downpours.  The leaking appears at the wall – floor seams after these sustained conditions occur and may even continue to seep even after the rains stop.  This is because the ground water is building up around your foundation from below and has nowhere to go other than in to your basement until the water subsides to below your floor level.  In this scenario an interior basement waterproofing system will catch the water from below the floor level and prevent the buildup, relieving the hydrostatic pressure that pushes the water in.  Ok, so to call it “waterproofing” is not the best definition since it is actually a ground water control system also called a hydrostatic pressure relief system.  The term interior basement waterproofing has become the generic label for these systems although technically it does not consist of a waterproof membrane.  Nonetheless, you will have a guaranteed dry basement with an interior drainage system if you have a ground water problem.

Beware that not all interior basement waterproofing systems are equal.  Some systems are channels that are installed level under the floor or on top of the footer.  Level is the operative word here, level means water lays in there and creepy bugs love water.  Look for systems that consist of a true footer drain installed below the floor and is pitched to run downhill to the evacuation point. Furthermore, any water that is building up under the floor has to push up into the drain on top of the footer to get to the drain maintaining the water level at a very high point.

So do you think you are figuring out whether you need exterior basement waterproofing or interior basement waterproofing?  Give Pioneer a call for a free no obligation inspection and estimate.  All options are reviewed with pros and cons for your specific foundation.  No sales games, no pressure, just straightforward conversation.


Exterior basement waterproofing or interior basement waterproofing?

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