French Quarter Row House
1890 single-house, East Bay Street · Cast-iron stack replacement + water service upgrade · ARB-approved · Completed 2023
The assignment
A 1890s single-house (Charleston's signature three-story residential form) with original cast-iron stack and lead service line. The homeowner was experiencing slow drains, occasional backups in the basement, and was concerned about lead in the drinking water. Their architect engaged us to design a retrofit that would:
- Replace the failing cast-iron drain stack
- Remove the lead service line
- Maintain all historic interior finishes (plaster, exposed joinery, original flooring)
- Secure Board of Architectural Review approval
- Complete work with minimal site disruption
What we found
CCTV inspection of the cast-iron stack revealed significant corrosion in the lower two runs (basement and first floor) and a 2-inch diameter reduction in the upper stack due to internal rust buildup. The stack was restricting drainage and risking sewage seepage into the basement walls.
The water service line traced from the street (approximately 80 feet) to the home. The entire run was lead, with the last 15 feet visible in the basement. Water testing confirmed elevated lead levels (14 µg/L, above the EPA action level of 15 µg/L).
The approach
Coordination with architect (3 weeks)
The architect created interior finish drawings for kitchen and bathroom work. We coordinated plumbing routing to avoid conflicts with other trade work and to minimize wall penetrations.
BAR pre-application (1 week)
We met with BAR staff to discuss the proposed work. Since the stack runs entirely interior, no exterior modification approval was needed. BAR staff indicated they would likely approve any reasonable plan.
Design & submittals (2 weeks)
We created detailed drawings showing the new PVC stack routing through existing floor cavities and crawl spaces. We coordinated with the structural engineer to confirm floor support was adequate. Materials and finishes were specified in the submittal.
BAR approval (4 weeks)
Application was submitted and reviewed at BAR's bi-weekly meeting. No public concerns were raised. Certificate of Appropriateness was issued on 2023-04-18.
Demolition & replacement (4 weeks)
We removed the old cast-iron stack in sections, supporting floors as we went. New 4-inch PVC stack was installed and connected to all drain runs on each floor. The new stack vented through the roof using a roof flashing compatible with the original slate shingles.
Water service upgrade (3 weeks, parallel)
We removed lead service line from street to home and replaced with PEX (½-inch cross-linked polyethylene). Routing was concealed in basement and crawl spaces. New line entered the home at the foundation and connected to the main pressure tank.
Testing & compliance (2 weeks)
Smoke tests and dye tests confirmed all drain connections were tight. Pressure test on the water line confirmed no leaks. City plumbing inspector signed off on all work. Post-installation water test showed lead levels below 5 µg/L.
Before & After
Project details
Address: East Bay Street, Charleston Historic District
Year built: 1890
Building type: Single-house (residential)
Stories: 3
Stack material replaced: Cast iron → PVC (4-inch)
Water service: Lead → PEX ½-inch
BAR approval: Certificate of Appropriateness issued 2023-04-18
Duration: 14 weeks (approvals + work)
Lessons learned
Interior-only work simplifies BAR approval. Because the stack runs entirely inside walls, the Board approved our plan quickly and with minimal discussion. If the stack had exited through an exterior wall, approval might have required discussion about visible finishes.
Architect coordination prevents rework. By involving the architect early and sharing detailed drawings, we avoided conflicts with other trades and ensured efficient use of floor cavities for routing.
Modern materials work in historic buildings. PVC is not historically accurate, but it's durable, code-compliant, invisible in the floors, and cost-effective. The homeowner appreciates the 50+ year design life and warranty.