The Problem:
The homeowner in Merrick, NY was experiencing ongoing water and moisture intrusion along the basement perimeter walls. During periods of heavy rain and high groundwater levels, water would seep through the foundation and collect along the slab edges. Over time, this moisture compromised interior materials such as wall paneling and insulation and created conditions that could lead to mold growth and structural deterioration.
The homeowner needed a long term waterproofing solution that addressed water at the footing level, protected the interior foundation walls, and restored the basement slab without disrupting the entire space.
The Solution:
The Zavza Seal team designed and installed a full interior French drain system to manage groundwater intrusion and redirect water safely away from the basement.
Preparation and Demolition
We began by carefully removing and discarding all interior materials that had been damaged by water, including deteriorated framing and insulation where necessary. Dust control measures were maintained throughout the process, and all demolition debris was removed from the property daily to keep the space safe and clean.
Trench and Drain Installation
A strip of the concrete slab, approximately 8 inches wide, was saw cut and removed along the full 156 linear feet of the basement perimeter wall. The trench was excavated down to the bottom of the footing to intercept groundwater at its entry point.
A 2 inch bed of washed gravel was installed at the base of the trench. We then placed a 4 inch perforated PVC drain pipe wrapped in soil separator fabric. The pipe was fully surrounded with washed gravel to prevent clogging and allow unrestricted water flow. The drainage system was directed into a new durable sump pump basin connected to a duplex sump pump system for reliable water removal.
Waterproofing and Vapor Protection
To further protect the basement, a Delta brand high performance dimpled waterproofing membrane was mechanically fastened to the foundation wall. The membrane extended 2 inches above slab level to channel incidental wall moisture directly into the French drain system.
A vapor barrier was installed over the system to prevent moisture vapor from migrating up through the concrete slab, helping maintain a drier and healthier basement environment.
Concrete Restoration
Once the drainage system was fully installed, we poured a new 4 inch thick, 4,000 PSI wire reinforced concrete slab over the trench. The concrete was troweled smooth and finished flush with the existing slab, restoring the basement floor and completing the waterproofing system.
The Result:
The completed interior French drain system successfully eliminated water intrusion along the basement perimeter. The basement is now dry, protected from future groundwater issues, and structurally reinforced at the slab level. The homeowner gained peace of mind knowing the system is designed for long term performance, even during heavy rain events common in Merrick and throughout Long Island.
This project is another example of Zavza Seal delivering durable, professional basement waterproofing solutions tailored to each home’s conditions.