Town/Neighborhood: Greenport
Borough/County: Suffolk County
Construction Type: Residential
Category: Foundation Waterproofing, Below-Grade Concrete Slab Removal, Foundation Drainage Installation
Problem
A homeowner in Greenport, NY reached out to Zavza Seal for help with active water intrusion along two exterior foundation walls. The issue had led to excessive moisture in the basement area and was compromising the integrity of a 15-inch thick concrete slab located below grade. The property’s foundation, primarily built with cinder blocks, was particularly vulnerable to water pressure buildup, which could lead to bowing or settling over time.
Solution
Our team designed a complete waterproofing and foundation drainage solution that addressed both the concrete slab and the adjacent walls to ensure long-term performance and protection.
Step 1: Concrete Slab Removal (28 sq. ft.)
We began by carefully removing and discarding the 15-inch thick below-grade concrete slab, totaling approximately 28 square feet. This removal was necessary to access the affected foundation walls and eliminate the trapped moisture contributing to water intrusion.
Step 2: Excavation and Surface Preparation
Our crew excavated along two exterior foundation walls:
- East Wall: 30 linear feet
- South Wall: 12 linear feet from the southeast corner moving southwest
We dug down to the bottom of the footing, exposing the entire wall surface. Using steel brushes, we cleaned off dirt, loose material, and old coatings. Any cracks or surface defects were repaired using 4.5 oz reinforced fibermesh embedded in waterproofing cement for added strength and adhesion.
Step 3: Waterproofing Membrane and Liquid Sealant
Once the wall surface was clean and repaired, we applied a liquid waterproofing rubber coating to the entire exposed foundation wall and footing. This sealant forms a seamless barrier, resisting moisture penetration even in high water table conditions.
We followed with the installation of a Delta brand heavy-duty dimpled waterproofing membrane. This advanced system features:
- Recycled HDPE on the inside
- Virgin high-density polyethylene on the outside
- A vacuum-formed dimpled pattern to direct water into the drain system
This dual-layer membrane provides unmatched durability, drainage, and long-term protection.
Step 4: Pressure Relief and Drainage System
To alleviate hydrostatic pressure, especially important for cinder block foundations, we installed a 4-inch perforated PVC pressure relief pipe alongside the footing. The pipe was surrounded by gravel and encased in filter fabric to prevent clogging. This system ensures that any incidental water is effectively redirected away from the foundation, preventing bowing and water buildup.
Step 5: Backfilling and Site Restoration
After completing the waterproofing system:
- We backfilled the excavation to original grade
- Graded the soil to slope away from the foundation
- Tamped the soil using a plate compactor to ensure a firm and stable finish
Results
The Greenport homeowner now benefits from a durable and complete foundation waterproofing system, tailored to withstand coastal moisture challenges and prevent structural damage. By combining liquid rubber sealant, a Delta dimpled membrane, and a foundation drain system, the basement and foundation are now fully protected against future water intrusion.
Looking for professional foundation waterproofing in Greenport or across Suffolk County?