Finding Flood Causes & Solving

Everyone’s flooding solution story starts with the same question: “what can I do?”  

Here is another story of “how I did it.”  

We like this step-by-step story because it shows smaller to bigger solutions, but also collaboration with the neighbor, and a surprise source of flooding water (read to end).

FYI: Small Biz

Flooding during basement work

Now to the story….

This Brooklyn homeowner's experience with flooding began in 2006 during a renovation that involved lowering the basement floor to make more useable space. As is the case with many older homes, the change to lower levels inadvertently also made their basement more susceptible to flooding.

Deciding to deal with it in better way

So after a few incidents and knowing more water was coming, he decided to tackle it in a systematic way; identify the various water pathways and then mitigate for each one. But to do that, he had to consider ALL the possible sources of water, including OUTSIDE, INSIDE, and also UNDERGROUND.

Map of his area that includes groundwater, courtesy of Field Form:

With underground water ruled out as a source, he moved on…

Step 1: Starting Outside: Re-Grade the Patio

The original cement patio of this older building was sloped toward the house (common issue and sometimes happens from settling). But grading can be hard to see and subtle. He saw pooling and knew that was likely directing hundreds of gallons of rainwater straight towards the basement door and two small drains. (Flood Facts: how many gallons comes from 1 inch of rain).

So he removed the old hardscape cement and changed the grade so it leaned slightly away from the house and replaced it with bluestone. Note: pavers like bluestone can be set close together or with some spacing to allow water to drain into the ground.

Knowing that the water needed to go somewhere and the small yard would not handle it, he also installed a small “dry well” at edge of the patio, which was really just a trench-pit lined with landscaping fabric and full of rocks, but a good place for water to go and be held.

Step 2: Install Simple Drain Guards

Leaves and debris frequently clogged the outdoor drains, leading to water pooling and potential flooding. (This happens in city sewer grates as well - see related story).

Recognizing that, he found special drain guards which are designed to handle stuff landing on top and prevent debris from blocking the drains, ensuring smooth water flow during storms. A $40 solution for flooding.

Step 3: Set Up Water Alarms

Many people check weather apps and worry when it rains. Another way to reduce worry and still keep an “eye” on things is through water sensors which send alerts to your phone about flooding. He installed a pack of water sensors in their basement AND in his neighbor's basement (helping your neighbor can help you 😅). So if and when water hits the sensor, it sends notifications to their smartphones. A $48 solution.

Step 4: Fix the Neighbor’s Downspout

Again, knowing the neighbor’s water was also his water, he noticed that the neighbor's downspout was misaligned and spilling a lot of water out.

So he had his roofer correct the issue which also prevented water from entering the neighbor's second-floor window during rainstorms.

Step 5: Checking Sewer Lines and Downspouts

Even if water goes to the right places, sometimes it gets blocked. Tree roots can infiltrate, things shift, or pipes get gunked up with all sorts of stuff (see below).

Knowing that his connection included old cast iron and even clay pipes, he and his neighbor did two things:

1) hired professionals to clear out the roots around the old sewer lines

2) did visual scoping in both in the downspouts and sewer lines

This inspection confirmed that there were no leaks or cracks, eliminating a key part of his flooding and drainage puzzle.

Gunked up. Ewwwww…but important: these are NOT from his place but here a few examples from the Ajax Sewer page showing what might be blocking your drainage and causing flooding:

Step 6: Expand French Drain, Put Pump In Pit

Inside, the basement already had a partial french drain but it was tied into the house drain (gravity fed) with a small pit as an emergency overflow. But there was no sump pump in it.

So, he had the existing french drain system extended to cover more of the basement perimeter and get closer to door and trouble spots.

Extending French Drain

Since the smaller pit was just a hole, he put in a proper pit liner and added an automatic sump pump to push the water out.

New Sump Pump

Closing It Up (Peace of Mind Underground)

With the new system in place near the trouble spot, he closed it up. But…just in case the new pump couldn’t handle things…he put an additional water sensor alarm ABOVE the new pump to alert him if flooding water was rising above it.

Step 7: Waterproofing Masonry Wall in Back

Wait, there was more!

Turns out there was another source of the flooding was discovered in a conversation with his roofer.

One day, they were standing in the back and looking up….the roofer pulled some paint off the back wall. He noticed what it was made of a latex topcoat, which allowed water to go BEHIND the paint, down the walls and into the porous brick and to the basement. Depending on which way the wind was blowing during the rain, that can add hundreds of gallons of water moving down a wall. This was another potential flooding source.

So he brought in a masonry specialist to power-wash the wall, re-point the brick, and apply a proper cementitious stucco (see options below). This restoration addressed hidden mortar gaps and significantly reduced water moving down the wall into the basement.

Examples of Coatings For Older Brick Walls:

• Cement coatings with rubbery component like Sikagard FlexCoat are polymerized cementitious coatings that offer waterproof protection and allow vapor to escape.

• Silicate mineral paints for stucco like Beeck Mineral Paints that seal out water but allow any trapped water to escape as a vapor. (Have used this personally and it’s not cheap but seems to work well).

• Waterproof acrylic paint like DRYLOK Extreme Masonry Waterproofer which claims it can keep water out even in hurricane conditions.

Flooding Solution Ingredient = Neighbors

This story shows the journey that so many people in are grappling with, in NYC and other places. It is hard to juggle the detective work for finding the sources and the solutions (and the costs!).

But one thing stands out here is his willingness to help his neighbor while helping solve his own flooding needs. Property lines are not something water pays attention to. Flooding solutions will work better when neighbors work together. After all, water connects us. 😅

Further Resources

• Flood Maps From Field Form

• Drain Defender Outdoor Stairwell Drain Cover

• YoLink Water Leak Sensors

• John Roggenkamp Roofing

• Ajax Sewer Cleaning Corp

• Mendola Waterproofing

• Ways To Keep The Water Out: Two Homeowners in NYC

• Clear Pipes, From Digging To Seeing

• One Guys Solution to Let The Water In

Share Your Story

Have you implemented solutions to combat flooding in your home? Share your experiences and insights with us at The City Sponge. Your story could inspire and guide others facing similar challenges.

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Please help us and share The City Sponge with others. Neighbors. Block Associations. Educating people on the days in between storms is the idea.

Thank you!