Home Interior Design A Comprehensive Guide About Waterproofing Basement Walls From Inside

A Comprehensive Guide About Waterproofing Basement Walls From Inside

A Comprehensive Guide About Waterproofing Basement Walls From Inside

Investigate the causes and find the solutions to your wet basement walls; the sooner, the better, to maintain the integrity of your home. Basements tend to absorb water because they are built below grade. The basement walls may occasionally become moist; water may puddle here and there, or, worst-case scenario, you may experience flooding during the rainy season. When basements become damp, mold or mildew may grow, wood may rot, and stored items may be damaged.

Waterproofing Basement Walls

Although basements are waterproofed during construction, houses settle over time, causing cracks to appear in the basement walls. Water can seep through these cracks when the soil outside becomes saturated. Water can be absorbed from the soil and transferred to the basement interior, making the basement walls feel wet even if they are structurally sound. The basement becomes more humid as the water evaporates from the walls. If you want to eliminate excess humidity in your basement, a good dehumidifier can help, but waterproofing the walls is the most effective long-term solution.

It may be possible to fix the problem yourself or hire a foundation contractor, depending on the cause of the moisture problem. Here are some tips to start right when waterproofing basement walls.

How to find waterproof basement walls from inside?

Find out where the water is coming from

Wet streaks often show up where water has entered the concrete because of its porous nature if you find stripes along cracks, under windows, between mortar joints (if you have cement block walls), and around pipes, such as a water supply or sewer line, look closely.

However, further investigation will be necessary if the entire wall surfaces are wet. A simple condensation test can be conducted by drying an area of the wall with a rag and then attaching a one-foot square piece of aluminum foil to the wall with duct tape. Check the underside of the foil after 24 hours by peeling it off. Whenever the wall is wet, water seeps in from the outside. Usually, if the basement is dry, the moisture is coming from elsewhere, probably from the basement shower. It can be remedied by installing a vent fan in the bathroom to direct steam outside.

If there is standing water in the basement, do not repair the walls

Cracks in basement walls can allow one or two inches of water to seep during a rainy season, but remove all the water from the floor before repairing the crack. When working in a flooded basement, you are more likely to experience an electrical shock. Remove the water by shutting off the power to the basement and using an extension cord that reaches an upstairs outlet to remove the water. Water is discharged from the pump via a garden hose to the surface of your lawn. Proceed with inspecting, repairing, and effectively waterproofing the basement walls when the basement is free from water.

Apply hydraulic cement to cracks

The bottom of the basement walls is another area where cracks are common. To pour a foundation, the footing, a broad flat base made of concrete and steel, is run first, followed by the walls after the floors have hardened. Even though this is a standard construction procedure, it can create a so-called “cold joint,” which is a weakness in the foundation between the footing and the wall where cracks can form from soil shifting and settling and pressure from the soil.

Fortunately, sealing cracks is a relatively simple DIY job involving hydraulic cement (from Home Depot), such as QUIKRETE’s Hydraulic Water-Stop Cement. Using water to make hydraulic cement into a heavy putty consistency, hydraulic cement is mixed with additives that cause it to expand and set quickly. The adhesive is then applied into cracks using gloved fingers or a putty knife (follow mixing and application instructions). In addition to expanding, hydraulic cement forms a watertight bond as it pushes deep into cracks and crevices. But you should only mix as much as you can use within three minutes since it starts to set quickly.

Don’t forget to fix leaky window wells

Basement wall leaks are typically caused by window wells that retain water if a proper drainage system beneath the well was not installed during construction. As a result, water may accumulate around the bottom of the basement window and then seep in.

It’s difficult to install a window well drainage system after being installed. Instead, dig approximately two feet lower in the excellent area and fill it with gravel to encourage rainwater to drain instead of collecting in the window well. Then, it would be best to caulk around the window with a silicone caulk on masonry, such as GE’s 100 Percent Silicone Window & Door Caulk (available at Home Depot). Additionally, install a window well cover with a sloped roof, such as Shape Product’s Universal Fit Polycarbonate Window Well Cover (available at Home Depot), to eliminate rainwater accumulation.

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It would be best if you waterproofed bare interior basement walls with masonry waterproofing

You can finish your basement walls with high-quality waterproof paint (available at Home Depot), such as DRYLOK White Extreme Waterproofed (if you discovered water soaking through your basement walls). Sealants of this type come premixed and can be applied just like paint. To waterproof basement walls, apply the paint thick enough to fill all the surface holes, then allow it to dry completely before applying a second coat. As the sealant dries completely, it forms a watertight bond that penetrates further. A 5-gallon container can treat approximately 500 square feet.

Paint or efflorescence should not be sealed with a sealer

You or previous owners may have painted the basement walls. To apply sealer, you’ll need to remove the paint. Sealer adheres only to bare masonry. Most older homes have several layers of paint, which can be removed with a sandblaster by professionals called blasting contractors. It can also be removed by wire brushing, an inexpensive but tedious task that requires some effort. The efflorescence, the white deposit that forms on concrete walls subjected to constant moisture, must also be removed before sealer can be applied; use muriatic acid (follow the manufacturer’s instructions).


There is no doubt that a leaky basement is a serious issue that can often be solved by a professional. In addition to causing damage to possessions and health hazards, water can also affect the structure of a home.

Keeping your  basement walls waterproof is one of the best ways to prevent leaks (and callbacks). Several techniques can be used to create a barrier that prevents water from penetrating into walls, including waterproof coatings.