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Basement Waterproofing

Concerns about water damage



Cincinnati basements are usually the area of ​​a building most at risk of water damage because they are below ground level and surrounded by soil. The soil releases the water it has absorbed during rain or snowmelt, and water can end up in the basement through leaks or cracks. Water can even migrate through solid concrete walls through capillary action, a phenomenon where liquid rises spontaneously in a narrow space such as a thin pipe, or through porous materials. Damp basements can cause problems that include peeling paint, toxic mold contamination, building rot, foundation collapse, and termite damage. Even indoor air quality can be affected if naturally occurring gases released by the soil are carried into the basement.


Proper basement waterproofing will reduce the risk of damage from moisture or water. Homeowners will want to be aware of what they can do to keep their basements dry and safe from damage. Inspectors can also benefit from knowing these basic strategies for preventing leaks and flooding.


Prevent water ingress by diverting it away from the foundation.


The primary concern is to prevent water from entering the basement by directing it away from the foundation. Poor roof drainage and surface runoff due to gutter failures and improper site grading can be the most common causes of wet basements. Addressing these issues will go a long way in ensuring that water does not seep into the basement.


Here are some measures to keep water away from the foundation:

Install and maintain gutters and downspouts to direct all storm water and snowmelt far enough away from the building foundation to ensure that it does not accumulate near the walls of the structure. At least 10 feet from the building is best, and where the water leaves the downspout, it should be allowed to flow freely away from the foundation rather than back up to it, and should not collect in pools.


The finish should be sloped away from the building for 10 to 15 feet. Low spots that can lead to pooling of water should be leveled to prevent the possibility of standing water near the foundations.


Shallow trenches called swales should be used in conditions where one or more sides of the building face upwards. The swale should slope away from the building for 10 to 15 feet, at which point another swale can be entered to direct the water around to the downslope side of the building and away from the foundation.


Repair all cracks and holes.

If there are leaks or leaks in the interior of the basement, water and moisture are most likely entering through small cracks or holes. Cracks or holes can be the result of several things. Poor workmanship during the original construction can show up in the form of cracks or holes. Water pressure from the outside can build up and force water through the walls. The house could settle and cause cracks in the floor or walls. Repairing all cracks and small holes will help prevent leaks and flooding.

Here are some steps to take if you suspect water is entering your basement through cracks or holes:


Identify areas where water may enter through cracks or holes by checking for moisture, leaks or discoloration. Every square inch of the basement should be examined, especially in cases where leakage or flooding is not obvious, but moisture accumulation is readily apparent.


A mixture of epoxy and latex cement can be used to fill small hairline cracks and holes. It is a waterproof formula that can help keep moisture and water out of basement walls. It is especially effective for very small cracks and holes.


Any cracks larger than about 1/8 inch should be filled with a mortar made of one part cement and two parts fine sand with just enough water to make a fairly stiff mortar. It should be firmly pressed into all parts of larger cracks and holes so that no air bubbles or pockets remain. As long as water is not forced through the basement walls due to external pressure, applying the mortar with an ordinary trowel will suffice, as long as special care is taken to completely fill all cracks.


If the water is pushed through by external pressure, a slightly different method of patching with mortar can be used. Areas of walls or floors with cracks should first be sculpted a little at the mouth of the crack and along its entire length. Using a chisel and hammer or cold chisel, cut a dovetail groove along the mouth of each crack you want to fill, then apply the mortar thoroughly. The dovetail, once filled, should be strong enough to withstand the pressure force that pushed the water through the crack.


Apply sodium silicate putty to the walls and floor.


Once all runoff has been thoroughly diverted away from the foundation and all cracks and holes have been repaired and there are no leaks, a waterproof sealant can be applied as a final measure.

Sodium silicate is a water-based compound that will actually penetrate the substrate up to 4 inches. Concrete, concrete blocks and masonry have lime as a natural component of their composition, which reacts with sodium silicate to form a solid crystalline structure that fills all the microscopic cracks, holes and pores of the substrate. No water vapor or gas will be able to penetrate by capillary action because the concrete and masonry have now hardened and thickened from the sodium silicate.

Here are some steps and tips to apply it:


Particular attention should be paid to the application of sodium silicate. It is an alkaline substance and as such can cause burns on contact with the skin and eyes. Inhalation may also cause respiratory irritation.


Sodium silicate must only be applied to bare concrete, concrete block or masonry that has been thoroughly cleaned and free of dirt, oil, adhesives, paint and grease. This will ensure that it properly penetrates the substrate and fills all microscopic cracks. It can be applied with a garden sprayer, roller or brush to a surface that has first been lightly dampened with a mop or brush. Apply two to three coats to the concrete, waiting 10 to 20 minutes between each application. Concrete blocks and masonry will take three to four coats, with the same 10 to 20 minutes between applications. Any excess should be wiped off afterwards. Sodium silicate should not be applied too much, otherwise it will not be completely absorbed by the substrate and will leave a white residue.


The paint can then be applied without worrying about water vapor getting trapped between the paint and the wall, possibly causing blisters and peeling. Tile or floor covering adhesives can also be used more effectively once the substrate is sealed.


Drainage of water away from the foundations so that it does not collect outside basement walls and floors is a key element in preventing flooding and water damage. Ensuring that any water that does end up near basement exteriors cannot enter through holes or cracks is also important, and sealing with a waterproof compound will help prevent water vapor or gas from penetrating, as well. By following these procedures, the risk of water-related issues in basement interiors can be greatly reduced, protecting the building from damage such as foundation rotting, mold growth, and peeling paint, as well as improving the interior air quality by blocking the transmission of gasses from the soil outside.


When you order a Cincinnati Home Inspection from LiteHouse Inspect, we will take a careful look at your foundation for any water intrusion issues.

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