Standing Water Under a James Island Home: A Full Encapsulation Case Study

The Problem

In March 2025, we received a call from a homeowner on James Island who had noticed a persistent musty smell throughout their first floor. The hardwood floors had developed soft spots near the kitchen, and their HVAC system was running constantly.

When we arrived for the free Crawlspace Blueprints inspection, the situation was immediately clear: the crawlspace had approximately 4 inches of standing water across 60% of its footprint.

Root Cause Analysis

• Failed vapor barrier — Original 6-mil poly had degraded and was providing zero moisture protection
• No sump system — No mechanism to remove water that entered during heavy rain events
• Open foundation vents — 8 open vents allowing warm, humid Lowcountry air to enter and condense

The Correction

We implemented a full encapsulation system over two days: 20-mil reinforced vapor barrier, French drain perimeter system, dual-pump sump pit, sealed foundation vents, and a 70-pint commercial dehumidifier.

Results — 30 Days Post-Installation

Relative humidity dropped from 94% to 48%. HVAC runtime decreased by an estimated 35%, and the soft spots in the hardwood floors stabilized as the subfloor dried out.