Most homeowners have no idea what actually happens during a basement waterproofing job. They get a quote, sign a contract, and four to six weeks later a crew shows up. This post walks through the four-day timeline for a typical interior drainage installation in a 1,400 square foot basement in Fairfield County, with notes on what to expect and what to ask about.
Day 1: Demo and trench cutting
The crew arrives between 7:30 and 8:00 AM with a concrete saw, a small jackhammer, and contractor-grade dust shrouds. The first task is cutting a six to eight inch wide channel in the concrete slab along the inside perimeter of the affected walls. This is the loudest, dustiest day of the project. Plan to be out of the house if you can, or at least keep doors to the basement closed.
By late afternoon the channel is cut, the concrete debris is removed (we haul it out, not the homeowner), and the soil beneath is excavated down to the bottom of the footing.
Day 2: Drainage system installation
The drainage system goes in. This is typically a perforated pipe (rigid PVC or specialty drain board, depending on the wall condition) sitting on a bed of clean gravel inside the trench. The pipe gets wrapped in a filter fabric to prevent silt clogging, then more gravel goes on top.
If the project includes a sump pump install or replacement, the new basin is dug in on Day 2 as well. The discharge line gets routed to the exterior, with frost-proof fittings at the wall penetration.
Day 3: Wall vapor barrier and concrete patch
A dimpled plastic vapor barrier is installed against the wall surface, hanging down into the trench. This routes any wall seepage down into the drainage channel instead of out onto the basement floor.
New concrete is poured over the gravel to restore the slab. Most jobs use a high-early-strength mix so it can be walked on within 24 hours. The finish is troweled smooth and feathered into the existing slab edge.
Day 4: Sump pump finish, cleanup, and walkthrough
The sump pump is wired in, tested under load (we run the bucket test in front of the homeowner), and the cover plate is installed. The discharge line gets a final freeze-protection check at the exterior.
The basement gets a thorough cleanup, plastic sheeting comes down, and we walk through the system with the homeowner. We explain what to expect from the pump (how often it cycles, what sounds are normal, when to call us), point out the cleanout access, and review the warranty documentation.
Final payment is collected after the walkthrough, not before.
What you should ask before you sign
- Is the drainage system pipe or drain board? Both work; the right choice depends on wall condition.
- Is the sump pump warranty separate from the workmanship warranty?
- Is the discharge line freeze-protected at the wall exit?
- What is the cleanout access plan if the system ever needs flushing?
- Are concrete patches feathered into the existing slab or do they leave a visible step?
A contractor who cannot answer those clearly is not the one you want.
Cost expectations
For a 1,400 square foot basement with full perimeter interior drainage and a new sump pump, typical CT and Westchester pricing in 2026 is in the $9,000 to $14,000 range depending on access, wall condition, and existing slab thickness. We put every number in writing before you commit.