Managing Water & Moisture in the Basement

Water and Moisture in the Basement / What are the options? 06.24.16

Water and moisture concerns and issues in the basement area, have become a very delicate issue, as the presence of mold has become a major health concern.

It was not long ago that the answer to the issue was simply, stay out of the basement. Basements were used as cold storage for vegetables and root crops, or they were merely the space under the house, which no one ventured into.

Due to the rapidly increasing value of real estate and the identification of value, based upon the livable square footage of usable space within a structure, the importance of utilization of all square footage available, under the roof, is both of practical and economic importance. The more usable space finished under the roof, the more valuable the property and resale value.

Based upon health, economic and practical concerns, the establishment of a dry basement has become a critical issue with homeowners. Whether the space is used for storage or livable space, dryness is important, and the less humidity and moisture in the basement level the better.

The fundamental aspects of the basement area, which is surrounded by concrete, masonry or brick, and many times, walls that are not insulated on the exterior or the interior, invite moisture, mildew and mold.

Waterproofing foundation principals for a new home;

  • The grading of the site is critical to the build- up of water along the foundation walls. If the grade is sloped towards the foundation, water will drain and accumulate against the foundation wall. It is much more preferable to grade the surface of the ground away from the foundation walls to minimize any accumulation of water. If this is impossible, the installation of what is known as a trench drain is recommended.
  • Surface ponding of water, even away from the foundation, allows a potential routing of this water towards the foundation walls. The water pressure exerted by standing water, can force moisture through the route of least resistance, which could be directly underground, towards your foundation.
  • All foundation walls and footings should be covered with a waterproofing membrane to eliminate the possibility of water penetrating the foundation or footing.
  • New foundations should be installed with a full waterproofing membrane; this would consist of a layer of impervious mastic on the immediate foundation surface, a layer of drainage board over the top of this mastic layer, and then a protection board over the drainage layer. In this manner, water will penetrate through the protection board, to the drainage layer, and will drain vertically down to the what should be installed, a footing drain.
  • The installation of a full perimeter footing drain is highly recommended. This installation consists of a 4 or 6 inch PVC perforated pipe surrounding the entire foundation. This pipe should be installed at the bottom elevation of the wall footing. This footing drain should be embedded in clean gravel and wrapped with a filter type fabric to prevent the contamination of the foundation footing drain with fines from the surrounding soils. This footing drain should either terminate out to grade (meaning the daylight) or a sump pit, with a pump, or a drywell. Each of these elements of a foundation drain is specifically described in another discussion within this website.
  • If the foundation area is full of water, as noted by the waters presence upon excavation, the foundation is located directly on a body of water or the pre-drilled borings indicated a high water table, the installation of the foundation should include an engineered de-watering system. A de-watering system is a series of drainage pipes, sump pits and mechanical pumps, that are automatically engineered to maintain the level of water below the bottom of the basement slab. This system is highly recommended if the environment indicates obvious water issues, and the costs are extremely reasonable, if matched against the damages caused by a wet basement.


Waterproofing foundation principals for an existing home;

It is obvious that waterproofing a basement when the construction is new and the entire foundation is exposed is entirely different, than waterproofing a home that is already in existence and is having moisture or water issues in the basement.

There are several franchised companies that are making a wonderful living offering solutions to existing foundation moisture or water issues. Basically these companies have specific patented, solutions to water conditions and will offer the following;

  • Evaluation of the specific issues being experienced by the homeowner. Simply stated, how much water is actually entering the basement level. Is the problem simply a moisture condition that can be solved by the installation of a dehumidification system, whether free standing or mechanically designed and installed? Is the situation more severe, and there are degrees of severity. Do the walls become wet, is there flowing water entering the foundation through cracks and failures in the foundation wall, is the water percolating up from the foundation floor, is there consistent standing water in the basement, etc. etc. ? Each situation will have specific problem issues that must be evaluated on an individual basis.
  • Once the evaluation has been completed, there will be a recommendation, offering varying methods of correction. What are some of the possible corrections?
  • As previously noted, a simple or more sophisticated means of dehumidification systems that will “ dry out “ the basement environment, eliminating moldy conditions and any negative factors of a high humidity environment.
  • Installation of an interior, perimeter system of water collection, that will lead to a sump pit and pump, a gravity exit to daylight, or the termination of the system into a dry well, that is designed to drain the water as required.
  • Installation of an external, perimeter system of water collection, that could include the excavation of the exterior of the foundation walls, the installation of a perimeter drainage system, the installation of a wall membrane, drainage board system, as described previously for a new foundation.
  • Installation of an exterior trench drainage system, together with other systems already described, to eliminate the entry of water and moisture into the basement environment.
  • Final monitoring of the systems, to ensure that the objective of a dry basement has been solved by whatever systems of basement dewatering, moisture protection, etc. has been installed. This monitoring is normally supported by a warranty period, in which, the contractor warrants a dry basement for a pre-set number of years.

There is no basement water situation that cannot be resolved. The balance of expenditure, with the convenience of a dry basement, as well as the usability, is up to the individual property owner. Technology has advanced to a point where there are extremely reliable products to provide watertight membranes on the foundation footings, walls and slabs, sump pumps and controls that are basically foolproof in their operation, emergency generator systems that will operate the dewatering systems if power fails, exterior trench drains that are specifically designed to alleviate negative water conditions.

As I have suggested many times within this website, the use of a professional construction consultant ,that is familiar with your location and the issues of water penetration within the foundations of your neighbors, would be extremely beneficial in suggesting solutions. However, in this specific case, the number of companies specializing in basement waterproofing throughout the country has provided the property owner with several options for professional guidance.

It is recommended that even if the home is brand new, a foundation waterproofing expert be notified and hired to provide full service or consultation, regarding waterproofing your foundation. The ability to perform the work as the foundation is being installed should NOT be overlooked, and the insight that these companies now have to solve existing water issues is tremendous.

This industry has developed tremendously in the last 10 years and the expertise of these companies should be used to offer a solution to your waterproofing problems. The use of your basement should NOT be overlooked, due to moisture concerns. The use of interior square footage in today’s real estate market is far too valuable to waste the basement square footage, due to water or moisture concerns.


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