Stone Foundation: Ways You Can Prevent Water Leaks

Exterior Stone Foundation

Share this Post

A stone foundation’s primary purpose is to keep out moisture and insulate a home from the cold. There are several types of foundations found in houses. A full basement above or below ground, a slab on the main floor, or a crawlspace. The type of foundation depends on the house design, location, climate, and soil moisture.

An older home from the pre-war era is more likely to have a stone foundation. Homes constructed before World War One have a stone foundation. After WWI, they began to build foundations with concrete blocks or poured concrete. These materials became popular and more widely used than stone because of the accessibility and inexpensive costs.

Types of Stone Foundation

Here are the three types of stone foundations:

Rubble: Flat stones that are of different sizes and shapes. Rubble stone foundations, in most cases, lack a binding agent. Therefore condensation can make its way into the foundation.

Fieldstone: These are foundational stones of similar sizes. This foundation is without a binding agent and is placed together based on the stone’s cut.

Dressed stone: Commonly referred to as cut stones are bound together with mortar or concrete. This procedure provides access to water to the interior of the foundation.

It doesn’t matter which type of stone foundation is in a home; somebody should do additional waterproofing as a precautionary measure to prevent water from leaking through the stone foundation.

The issue with stone foundations as they age is that signs of water seepage may begin to appear. While stone walls are known for their durability and strength, most of these foundations are not waterproof. Problems can quickly reveal themselves when the house is not leveled or improperly built, which results in wall cracking, bowing, and water leakages.

Interior stone foundation wall cluttered with utility pipes and electrical.

Importance of Waterproofing The Foundation

Waterproofing protects more than just the structural support of a foundation. Other issues can arise from water leaking through the stone foundation. 

Growth of mold: A wet basement is a perfect environment for mold to thrive and grow.

Pungent odor: The combination of mold, standing water, and pests can create a strong foul smell.

Dampness and flooding: If there is dampness or flooding in the basement after it rains, it could be a telltale sign that the foundation is weak.

When water begins leaking through the basement foundation and walls, it signifies that the mortar joints are damaged. Leaking water happens because mortar is unaffected by water under certain conditions; it is not entirely waterproof because it’s not watertight.

With that in mind, it is necessary to waterproof stone walls to form a barrier against water. If water is unable to seep through the foundation, the risk of these issues is eliminated. People will often ignore the signs that water is leaking through the basement foundation and later claim the leak came out of nowhere. Some signs are present before you are standing in a flooded basement to indicate that there could be water leaking through the foundation.

You need waterproofing if you see these signs in a wet basement:

  • Unpleasant odors coming from the basement
  • Rotting wood, standing water, or wet areas of the floor in the basement
  • Damp and discolored stones
  • Bubbling, cracking, peeling paint, or wallpaper on surfaces
Stone foundation surrounded with backfill area and overwhelmed by water seepage.

What Causes a Wet Basement?

Several things contribute to a wet basement:

The soil around the home’s foundation is damp and expands, forcing pressure on the foundation, causing water to enter through cracks and other openings such as pipes and windows.

Water collects in the soil surrounding the foundation of the home, placing pressure on the foundation walls. The pressure causes the foundation to crack and water to seep in.

Stone Foundation Waterproofing Solutions

When the foundation of the home needs waterproofing, the options are either interior or exterior waterproofing. Here are the two waterproofing procedures in more detail:

Interior Waterproofing

There are many waterproofing products and installation service companies out there, but there is one common goal. The goal is to re-route water out of the basement and away from the house. 

Unfortunately, there are too many companies installing ineffective systems for a quick buck. The best way to remove the water is by installing a drainage system below the slab floor next to the footer. This drainage system uses pipe(s) packed in stone to catch leaks or groundwater penetrating the foundation. A combination of a drainboard, a thick vinyl vapor barrier, and 3.5+ inches of concrete replace the perimeter slab floor along the basement’s perimeter. 

Groundwater is collected in the pipe and gets directed to a sump pit. Inside the pit is a sump pump. The pump sucks in water and pumps it out and away from the basement and home, respectively.

Exterior Foundation Repair

An exterior foundation waterproofing repair requires more work than the interior waterproofing method and, in all cases, more expensive. It has a similar purpose to stop water from penetrating the foundation. 

The first step in exterior stone foundation repair is to excavate around the perimeter of the home’s foundation. Excavating requires the removal of sections of landscaping, walkways, decking, and driveways. It can be very disruptive.

Once the exterior foundation walls and footer are exposed, it’s time to remove the old mortar. Fresh mortar and a waterproof membrane are applied around the exterior walls. 

The drain tile (rigid or flexible pipe) is installed in the ground around the house. The drain tile is packed in stone, and loose dirt is placed on top of the stone. The groundwater is directed away from the foundation before penetrating foundation walls. Exterior waterproofing systems don’t hold up in the long run. That is why contractors rarely, if ever, offer a warranty for more than 10-years. A combination of silt clogging, root-intrusion, and disruptions caused by wildlife and insects can and will put your foundation in jeopardy again.

In Conclusion

Stone foundations are reliable and durable. Many homes with 500-year old foundations are still holding firm today, yet their biggest weakness is water seepage. Make sure to waterproof your basement with a proven subfloor system that can discharge groundwater away from your house. Don’t sacrifice the structural integrity of your foundation. Mold and mildew can affect your health and make life uncomfortable in your home. It is up to you. Make it last another 500-years.

If you have any questions, call American Dry Basement Systems at 888-748-2002.

What are Basement Engineering Tabs?

Basements should have engineering tabs made during basement waterproofing for a strong foundation. Leaving sections of your floor on the footer is vital.

backhoe making foundation clay bowl

Wet Basement Problem: False Water Table

A false water table is the primary cause of wet basements, deteriorating foundation walls, and cracking floors. It is “false” because it is temporary.


6 Ways to Prevent Basement Flooding

Basement flooding usually occurs when groundwater finds the path of least resistance. There are six things you can do to prevent flooding inside your basement.

monolithic slab foundation with poured concrete walls

What is a Monolithic Slab Foundation?

A monolithic slab foundation is created by pouring a single layer of concrete to form a slab and footing. The construction process is faster and low cost.