Basement Waterproofing Solutions

Published on April 5th, 2022

In this post, we’ll summarize all of the potential solutions for your wet basement. We will also discuss unrealistic solutions to give you a basic understanding of the possible remedies that have been tried over the years.

Keep in mind – we are addressing basement waterproofing solutions for wet basements with 1.25” to 1.5” or more of water. We will discuss damp basements, crawl spaces, humidity and condensation in an upcoming post. For now, we’ll focus on “wet basements” as defined above.

It is necessary to discuss the unrealistic basement waterproofing solutions as well as the successful ones to fully educate the reader on every aspect of basement waterproofing. In this way, the reader will understand and be aware of the waterproofing methods that do and do not work.

Ineffective Exterior Methods of Basement Waterproofing

1. Installing a sidewalk or pavement around a foundation. The concept of installing a walkway or pavement around the foundation to stop water from saturating the over-dig is an unrealistic solution. The theory to installing a sidewalk is that the sidewalk will stop the water from penetrating around the foundation in the over-dig area.

In reality, when the rainwater falls outside the sidewalk, it will seep down into the soil, saturate it and then find its way to the looser backfill under the sidewalk. This is not a permanent or effective measure to stop the basement from flooding.

2. Sodium Bentonite – Sodium Bentonite is a substance that was manufactured primarily for the iron and steel industry. Sodium Bentonite was manufactured in sheets and put over the iron and steel to stop rainwater from rusting the material. When the rain hit the Sodium Bentonite sheets, the sheets would form themselves around the iron or steel and “wrap” it to prevent the rusting. The sheets would soak up the water, thus stopping the water penetration. In the 1970’s, knowing the sheets were used in this way, a basement waterproofing company sought to powderize the Sodium Bentonite and inject it around the perimeter of the exterior of the house. The thought process was that the powder would seal the foundation wall and footing joint. Several companies jumped on this band wagon and began using the Sodium Bentonite across the country.

This method rarely worked. Water would seep underneath the foundation footing to the floor wall joint by the tubes inserted in the lawn to install the Sodium Bentonite. The method for installation of the powdered Bentonite was to put tubes in the lawn and inject the powder to intersect with the footing.

A series of lawsuits ensued and most of the companies that used the injected Sodium Bentonite methods were put out of business due to the numerous complaints.

It was common for these companies to state (in fine print) on the proposals that they would return – at an additional cost – and install a drainage system to stop the flooding, if the Sodium Bentonite did not work. However, be aware that there are still companies today that claim Sodium Bentonite works. This approach sounds attractive to the homeowner because there is no disruption inside the home, but usually Sodium Bentonite is not a cure for a flooded basement. Most reliable basement waterproofing companies do not offer Sodium Bentonite as a solution. The Sodium Bentonite sheets – placed on the foundation over the footing – may be suitable as a damp proofing method. But remember – water can still infiltrate underneath the footing and the virgin soil – so the flooding problem may continue. Be aware that in post-construction basement waterproofing, digging out around the perimeter and installing sheets of Sodium Bentonite is an ineffective and inadequate waterproofing solution.

3. Extending downspouts – Extending downspouts can help in directing rainwater away from the house and re-directing it to virgin soil. This way, the rainwater is not as prone to saturating the backfill area. This is helpful, but is not a primary or realistic means of stopping basement flooding. Downspouts should extend at least 10’ to 15’ away from the home. If you have a chronic problem, however, this will not solve the flooding.

4. Exterior French Drains – Exterior French drains are a realistic solution during construction. In fact, most new homes today do have an exterior french drain system. However, in a post-construction setting – when a water problem is diagnosed in a completed home – exterior French drains are not a realistic solution. With landscaping, decks and the necessity for heavy equipment to transverse the grounds, exterior French drains should be avoided once the house is built. Another negative factor is the fact that these systems can rarely be warranteed by legitimate companies.

Exterior French drains also tend to clog. During my tenure in the basement waterproofing industry, I have performed repairs at many homes with exterior french drains in place. The systems failed because of clogging with dirt. Although these systems can be wrapped with felt and back-filled with stone, dirt will still get into the stone and around the felt and can completely clog the system.

Another area of concern with exterior french drains is where the water should be drained. This can be a significant problem if the house is anywhere from 5’ to 8’ below grade and is running a pipe around the perimeter. This pipe needs to be pitched and dropped off to a point where the water may drain away. Some methods currently being used to accomplish this are dry wells, draining to a storm drain system or draining to an exterior or interior sump pump. These methods have the potential to be extremely unreliable.

The main reason that we do not recommend exterior french drains as a primary means of basement waterproofing is that they will clog. Catch basins and pits can fill up with water – supersaturating and causing backflow around the pipes – resulting in a bigger mess than you had before.

5. Damp Proofing – It is important to understand the difference between damp proofing and waterproofing. Damp proofing is a process that is used during new construction and consists of applying a coating on the exterior of the foundation wall. It is a common belief among homeowners that there is a damp proofing method on the exterior that will also provide waterproofing. The damp proofing method is a spray- on application on the exterior foundation wall to stop water from coming in through the tie-rod holes or through small wall cracks. This method will not permanently solve a floor/wall joint problem and should not be used in a post-construction basement waterproofing project.

It would be cost prohibitive to dig out around the foundation and at the very best, would be unreliable. Always remember, the water comes in from under and over the footing between the foundation wall and up through the floor.

6. Landscaping and Regrading – Landscaping and re-grading is a trial and error method at best. It cannot be expected to solve a flooding wet basement. It can help to stop water from coming in through the windows, bulkheads and sill plates. However, if there is a floor/ wall joint problem or floor/wall crack problem, landscaping and re-grading will not serve as a primary means of waterproofing. This method is experimental or speculative, at best.

7. Paints and Sealants – It is a common misconception that there is some sort of paint or sealant that will stop water from coming into a basement. When there is a major flooding situation, paints or sealants will not work in the basement. There is no paint or sealant product currently on the market that will permanently stop the water from coming in.

Realistic Interior Methods of Basement Waterproofing

1. Hydraulic Cement – Hydraulic cement has been installed where the wall meets the floor by many people for many years. Although this may work for a short period of time, it is surely not a permanent solution for basement waterproofing. Hydraulic cement is a special fast-setting cement that adheres to existing concrete. It will create a bond between the old concrete and the new hydraulic cement. Concrete shrinks and expands with the changing of the seasons and the difference in temperatures from the outside to the inside. The bond between the old and the new cement will (over a period of time) create a new crack which will eventually let the water in. That is why this method (although a realistic and viable approach) is not a permanent solution and will ultimately fail. Therefore, we do not recommend hydraulic cement as a permanent means of stopping water in a basement.

2. Epoxy and Polyurethane Injections – These types of injections are very reliable on wall cracks in poured foundation walls only. This method, however, does not work well on floor/wall joint seepage or in floor cracks. Although there are specialized methods of grouting and filling large voids underneath the basement floor as a means of waterproofing, I strongly suggest avoiding epoxy and polyurethane injections unless you are working on a poured foundation wall crack.

3. Interior French Drains (pipe and stone) – These types of systems have been used for years and do work – but have drawbacks. Although this is one of the more reliable types of systems currently available to homeowners, it can cause subsequent problems and has some flaws. French drains (pipe and stone) are installed at such a depth that they tend to “dredge” for water that is not necessary to be pumped out. Also, these types of systems can pull dirt from underneath the foundation footing, creating a void. This void brings the potential for walls dropping or settling which creates a significant trauma for the home and the homeowner.

These systems – due to the depth – make the pump remain very active and work very hard. The pump is, in essence, pumping out water that is not necessary to be pumped out. It would be more effective to simply address the water that is threatening the top of the floor. The water that is underneath the basement floor will always be present.

Although the interior french drain is the best method for waterproofing as discussed in this Chapter, there is a better technology which is far superior to the systems we have previously outlined here.

4. Baseboard Systems – The theory on baseboard systems is that when the water comes in where the floor meets the wall, it will be channeled in an above ground system mounted with epoxy to the basement floor. These systems work well, but if there is a crack in the center of the floor or if it is not leaking where the floor meets the wall, the system will not be effective. It works only on the perimeter.

5. Shallow Depth Interior Basement Drainage Systems – A few specialty companies have specialized sub-floor channels. These channels are the most reliable and least prone to failure of any other basement waterproofing method.

Questions? Let us know how we can help. Our team at Basement Technologies is here for you!

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