Basement Waterproofing FAQs

By understanding the physics of water-flow and chemical reactions around it, we ensure your basement will not leak from the walls or floor. Here are some common basement waterproofing FAQs:

1. Water will always flow from areas of high pressure to low pressure and will take the least resistive path possible.
2. When rainwater or snow infiltrates into the ground, it reacts with the organic matter around it and turns slightly acidic.
3. Concrete is slightly porous, and water will slowly weep through. Different concrete pours will not bond well together and will form a plane of weakness that water takes advantage of.
4. Lime, being one of the binding agents, or glue, in cement will slowly dissolve from the acidic groundwater. This lime is commonly precipitated as efflorescence on our walls when the water evaporates.
5. When houses are built, we typically excavate around the basement to install the footer and foundation walls. The builders back-fill the area with dirt. This space, called an excavated zone or back-filled area, is commonly more porous than the surrounding land.

Below are some Basement Waterproofing FAQs from customers of Quality Dry Basements.

Q: Why is Water Coming Through my Basement Floor?

Rainwater and groundwater (acidic) eventually fill the pore spaces within the excavated zone. This leads to hydrostatic pressure adding additional stress against your foundation. To reduce this pressure, water begins to seep inward through the concrete, eventually leaking into the basement. There are other interior and exterior factors involved in this as follows:

• Interior moisture sources of leaky pipes and other mechanical items in the basement can cause water to spill onto the walls and floor, leading to wet floors directly under and around the mechanical items, furnace, boiler, oil tank, hot water heater, well filter, etc.
• Ventilation from outside causes condensation along the cold water pipes, filter systems, water tanks, and more, which leads to wet floors where they drip down.

Q: How Does Water Get Into My Basement?

Hydrostatic pressure causes water to move through cracks, holes, or weak seams between the walls and floor. Water will always move from areas of higher pressure (back-filled area outside the home) to lower pressure (your basement). Two key reasons why this happens:

• Capillary suction (wicking), air leakage though walls or floors.
• Vapor diffusion through foundation walls and floors.

Q: I’ve Been Seeing Water Seepage in my Basement. What Causes This?

One of our most common basement waterproofing FAQs is why basements leak in the first place. First, let us consider our primary building material, cement. Whether it is a poured concrete foundation, cement blocks, or a stone wall, cement is used to hold everything together. It is also slightly porous, and moisture can slowly wick or seep through it. Another item to note is that dry cement and wet cement do not bond well together.

Therefore, any surface between two different cement pours will be a plane of weakness that water will come through. Hydrostatic pressure builds up due to groundwater in the back-filled zone around your house. This zone has higher porosity and permeability than the surrounding native soil on your property. Hence, more water can fill this area, leading to higher pressures. To complicate things, the groundwater reacts with the organic matter and becomes acidic, which causes chemical dissolution of the lime in the cement and mortar.

Water will always go from areas of higher pressure (back-filled zone) to lower pressure (your basement) and the acidic groundwater will ensure any cracks present get larger over time. The primary pathway water comes into basements is between the footer and the foundation wall. From there, it rises between the wall and the floor. Each of these items are poured at different times, thereby having planes of weaknesses that the water takes advantage.

Additional factors include:

• Inadequate draining – When builders initially build our homes, the generally place soil against the house and allow it to gently grade or slope away from the foundation walls. Over time the soil surrounding our homes will compact a little leading to the ground sloping back towards our foundation walls. As a homeowner, we should bring in additional soil and rock to reestablish the slope away from our homes.
• Defective or missing gutters and downspouts. – gutters should always move water away from the house. It’s best to have rainwater diverters that extend at least 5 feet from the house.
• Improperly designed window wells – Window wells should remain dry during heavy rains. Unfortunately, I have seen many window wells that collect water and become a fishbowl for the basement. This can lead to windows eventually leaking into the basement.

Q: How Can I Stop Water Seepage in my Basement Floor?

Another frequently asked basement waterproofing question we see is what can be done to fix basement water seepage problems leading to wet basements. Here are some solutions we provide to resolve your wet basement problems and ensure you and your family will enjoy a clean, dry basement for years to come.

• Move surface rainwater away from the house.
• Gutter placement and extending drain spouts beyond the back-filled zone around the house. (typically 3-5 feet beyond the house)
• Sloping landscaping away from house.
• Placing a foundation drain along the exterior of the house. This solution gets very expensive, very quickly, and is only guaranteed about a year, similar to other construction projects. Issues can arise with mud, roots, and silt clogging the drains, and potential collapses with 8 feet of rock and dirt overlying them.
• Placing a foundation drain along the interior of the basement. This solution is generally less expensive and solves many of the issues that the exterior drain encounters. There are three typical types of interior foundation drains, all of which lead to a sump pump:
  • A drain placed along the corner edge in the basement.
  • Placing a drainage system under floor, but above the foundation.
  • Placing the drainage system adjacent to the foundation – the lowest point available ensures the hydrostatic pressure decreases the most.

Our company specializes in the latter type of system, a sub-floor deep-pressure relief system.

Q: What is a Sub-Floor Deep-Pressure Relief System?

Our Sub-floor deep-pressure relief (SFDPR) system is designed to reduce the water pressure pushing on the foundation walls by removing the water inside and along the walls. If all the walls have a lower pressure on them, then the pressure under the floor is also reduced. Lowering the excess pressure around and under your home ensures the walls or floor do not leak.

Our system works best because we actively remove the water, we do not set up a system that just catches water as it seeps inside. We know how the water comes inside the house and redirect it to go into a system that will remove it. When heavy rains return and the water tries to reestablish the pressure, there is a preferred pathway for the water to go; hence the pressure remains low. It is this decrease of the excess acidic water pressure that ensures water will not leak into the basement and reduces the deterioration of the cement walls where the system is installed.

Our procedure includes drilling weep holes near the bottom of the foundation wall along the system to relieve water from inside the exterior walls and give the water coming through a preferred pathway to flow into the trench. Drilling these holes requires precision based on the type of foundation wall you have.

Our technicians are trained to know precisely how to drill these holes to ensure adequate drainage. The presence of the weep holes is key to allow water from within the cement block walls and the water that is coming under the foundation wall to drain into the system, in turn allowing water from the exterior to also drain from around the house. The depth of the perforated piping ensures the hydrostatic pressure drops to the level of the piping. Inside the trench, 4-inch perforated drain-pipe will be installed from a high elevation down to the sump basin to allow water to drain. The piping and trench will be covered and filled with gravel. A corrugated plastic sheet is placed above the pipe and gravel, folded, and allowed to rest against the wall. The plastic sheet is to redirect water coming through the weep holes down into the pipes below and to separate the new concrete from the trench. The trench is filled with cement to match the existing floor level.

When finished you should see approximately 2-3 inches of the plastic diverter against the wall and at floor level the entire length of the system. Your system is only as good as the pump removing the water. We currently install professional grade pumps that are ¾ hp stainless steel primary sump pumps. The pumps come with a five-year manufacturer’s transferable warranty and, depending on your groundwater chemistry, should last between 10-15 years.

We also have battery backup combo kits that have a primary and secondary pump attached to a battery. If you do not have a generator that will automatically turn on in the event of a power outage, then it is highly advisable to invest in one of these. This kit ensures at least one pump is always ready to remove your ground water.

Q: Why do we drill “Weep Holes”?

If you were to walk in a park or anywhere there may be terraced landscaping with a retaining wall, you may notice small holes or pipes sticking out near the lower portion of the wall. These are weep holes. Engineers intentionally put them in to allow the groundwater that will accumulate behind the wall to drain out. That excess water will place additional pressure on the wall that could cause the wall to collapse.

It is this buildup of excess water, also referred to as hydrostatic pressure, behind our foundation walls that lead to basements flooding. This pressure typically rises during times of heavy rains and snow melt. Water will move to areas of lower pressure and will take the least resistive path. This path is generally through holes, cracks, or weak seams between the walls and footer.

When we install a basement system, we intentionally drill weep holes in the lower part of the wall to allow that water pressure decrease and give the excess water a place to flow. Water is already coming through the wall; we just want to direct it where we want it to go. The water then flows down into the system to a pipe that typically leads to a sump pump. By reducing this pressure, we can save our foundation walls from additional deterioration and stop our walls from leaking. For more in depth information about weep holes and basement waterproofing FAQs we’ve included both audio and video explanations below.

Do you have Basement Waterproofing FAQs? Call us at (203) 529-3737 or CONTACT US to learn more about the right solution for you.