As home inspectors, we inspect hundreds of homes for potential home buyers, sellers and investors each year and basement moisture is one of the greatest concerns we hear from our clients.  The solutions and advice for fixing wet basements and crawl spaces seems to vary widely and some solutions are quite expensive and invasive.   After doing inspections for many years, we recognized that some of the simplest and least expensive solutions are not often recommended or even understood.  And unfortunately, many expensive systems are installed to help eliminate the moisture when simpler and cheaper options would have been sufficient or even superior.  That is why we are offering this advice to homeowners about wet basements.  So why should you listen to a home inspector and not a professional waterproofing company?  Remember this truth: Basement waterproofing companies are in business to sell waterproofing systems. Therefore, it is not in their best interest to offer advice on the simpler and sometimes less expensive solutions which can often be implemented by you, the homeowner.  These simpler methods will be the focus of our advice.

To Sump or Not to Sump?

We are not advocating to completely disregard the advice and waterproofing systems offered by reputable waterproofing or foundation repair companies. We are simply recommending the application of proven and less expensive methods before installing one of these costly internal drainage systems (sump pump systems).  We also believe that different foundation wall types respond in different ways to exterior water (with regard to water penetration).  Poured concrete foundations seem to accept sump systems quite well, as long as water is not penetrating through any settlement cracks.  However, sump systems may not always be the best solution for certain types of unitized wall structures (concrete block, brick and stone). Here’s why…

Concrete block, brick and stone foundation walls are built out of individual units stacked upon each other with mortar between their joints which binds the materials together.  Unfortunately, these mortar materials are prone to deterioration from exterior water and often deteriorate over time and become porous, failing to keep out the water.  This leads to water seepage directly through the wall unit joints and results in a wet basement or crawl space.  So why wouldn’t a sump system help in this case?  Essentially, sump pump systems do not eliminate water entry, they just move it from one place to another once the water has entered the sump system below the basement floor.  The water is “managed” but is still coming in.

To make matters worse, in unitized wall structures, moisture from outside can become trapped between the joints of the wall units or between finished surfaces which may allow wet conditions to go unnoticed for extended periods of time (especially in finished basements and in crawl spaces). While installing an internal drainage system would likely catch most of the water which came through the wall, it would do so only after that water has entered the basement and was channeled to the sump pump pit.  So, such a system will not prevent the water from deteriorating the foundation wall units, mortar or other foundation components upon which the upper framework of the home depends for stability. It is possible for a stone or block basement to seem dry all the while the foundation wall is slowly deteriorating.  That’s why sump pump systems are not always the best solution.  Only exterior water management will keep the water away from the foundation to begin with.

Therefore,  improving the performance of exterior water management components (gutters, downspouts and the sloping of soil/flatwork grades) would be the most appropriate solution in the example above.  Such improvements should be done in conjunction with sealing and repairing the deteriorated mortar joints at the foundation walls (inside and outside).   Exterior modifications are also likely to be less expensive and not require the work of a professional water proofing company.

Exterior Water Management

Directing water away from the foundation is the key.  Water can be very destructive to almost any material including wood, rock, steel, masonry and concrete.  So it must be managed or eliminated if at all possible. So how does one do that on the outside of a house? By implementing some or all of the following exterior solutions:

Proper exterior soil/flatwork grading. The proper sloping of the ground surfaces adjacent to the home’s foundation walls is perhaps the single greatest improvement that can be done outside.  The proper “grading” of the soils and concrete/asphalt flatwork will help channel rain water and melting snow away from the house in the first place.  Improvements to grading are a proven method for reducing wetness in basements.  However, not all properties or sites will allow improvements to the grading, especially when other homes or structures are placed very close to the foundation.  In these cases, other measures will likely be needed.

Also keep in mind that landscape boxes or terraces, if not designed right, can collect and hold water like a bathtub and allow that water to rest directly against the foundation wall.  We recommend all landscape boxes or terraces be constructed with proper drain systems to allow water to drain out and away from the house.

Improving the pitch of the soils which rest against the foundation walls will help direct water away from the structure.  In most cases, simply adding non-porous soils in a sloped fashion near the walls can significantly improve water runoff.  These soils must be impervious to water, like hard clays.  Such new soils should slope at a minimum of 1 inch for every foot and extend at least 6 feet away from the house.

Improving the pitch of your concrete or asphalt flatwork may require that the slabs be repositioned or sloped away from the foundation.  This will likely require what’s called “mudjacking”, where the slabs are “jacked” back into a desired position by injecting a concrete mixture below the slabs.  In some cases, however, mudjacking may not be possible.  In those cases, the flatwork may need to be removed and replaced or simply sealed where it meets the house.

Properly functioning gutter and downspout systems. Next to exterior grading, the proper function of the gutter and downspout systems is crucial to exterior water management. A gutter system does nothing more than handle the water that is shed from a roofing system or overhang.  If this system is clogged with debris, damaged or poorly designed, it won’t get the water where it needs to go.  For most homes, proper gutter function usually means nothing more than keeping the gutters clean and extending the downspouts away from the house.

There are a variety of ways to achieve proper gutter performance including regular cleanings and the installation of gutter guards or cap systems.  These systems channel water into the gutters but keep out the leaves, sticks and debris which clog the system.  Some gutter guards are excellent while others aren’t worth the time and money you put into them.  Be sure to do your due diligence when assessing these products.  Aside from installing gutter guards, one of the best things you can do is simply cut back the tree branches near the perimeter of the house.  The trees create the debris so the more you are willing to cut them back, the less debris you will have.

The gutter systems need to be installed and sloped properly in order for the entire system to work.  As home inspectors, we regularly see gutters which are improperly designed or installed and won’t allow for proper drainage.

Additionally, all downspouts must be free to drain and should be directed as far away from the house as possible.  Downspouts should never terminate right at the base of the foundation walls or in poor drainage pockets around the house.  For most downspouts, this means simply adding a drain extension or pipe.  Simple splash blocks typically do not direct the water far enough away from the house and are not recommended.  Proper downspout performance may also require the installation of subsurface drain pipes where the drain pipe is buried below soils.  This is especially true if various objects like sidewalks, landscape boxes or driveways are in the path of the drainage route.  If you bought your house with existing subsurface drains, you should test them with a garden hose to see how well (and where) they are draining.  Old subsurface drains are notorious for poor performance.  If in doubt, create a new drain.

Installation of French drains or swale drains. In some cases, exterior grading and gutter performance may not be enough to keep water away from the house.  In those cases, the installation of a French drain or swale drain system may be needed.  For example, some homes are built on steep slopes with soils tilted directly at the front or rear walls of the house.  Simply pitching soils against the rear wall wouldn’t be sufficient to halt the water.  A subsurface French or swale drain system may be the only way to go. Keep in mind that some of these systems may cost as much or more than a basement sump pump system.  But for reasons already stated, we feel it is still best to attempt to handle water outside first.  Check out this video for more details.

Additional videos have been added below for viewing other possible solutions.

Maintain solid foundation wall mortar. If the home’s foundation uses block or stone, the mortar in the walls must be maintained.  Although the maintenance of foundation wall mortar doesn’t directly help direct water away from the house, it should not be overlooked in the larger scope of water management improvement work.  Proper mortar conditions should be maintained at both the exterior and interior of the foundation walls so that any water which does hit the walls doesn’t find a way inside.

Good, short demonstration on keeping soils pitched away from house; Shows poor slope

Good, short demonstration on keeping soils pitched away from house; Shows good slope

Longer video; Inspector points out poor grading, high soils @ brick and downspout problems

Good mod length video with inspector pointing out poor drainage; Example where French drain application may be appropriate.

Short video that focuses on downspouts; Good and to the point

Flooded basement; not real helpful; just shows what we all want to avoid