Case file — Rockville, Montgomery County, MD. One of the 25 jobs in our 250-home series. New here? Start with our open letter.
At a glance
| Location | Rockville, Montgomery County, MD |
| The problem | A leaking crack in the foundation, with water reaching that wall from outside |
| The fix | The crack injected and finished, a 40-foot exterior French drain along the same wall, and a buried downspout run added later |
| Time on site | Two days together, then a return about two months on |
Three jobs, one problem
Our records hold three separate jobs at this address. Read as a list they look like three sales. Read in order they are one diagnosis, worked from the inside out.
One — the crack. Polyurethane grout injected into the crack under low pressure, then the packers cut off and the wall patched. That stops water coming through the wall today.
Two — the ground against that wall. About 40 feet of exterior French drain on the same elevation: a trench dug alongside the foundation, lined with non-woven geotextile, a 4-inch perforated pipe set in it, gravel backfilled and compacted to grade. Water in the soil now reaches the pipe instead of the wall.
Three — the roof. Two months later, another buried downspout and about 15 feet of solid 4-inch pipe, sloped and backfilled, ending in a pop-up emitter well away from the house.
Why not just the injection
Because an injected crack is a sealed crack, not a dry wall.
Grout fills the path through the concrete and it holds. But the water that found that crack is still arriving at that wall, still sitting in the soil against it, still under pressure every time it rains. The wall is now resisting that pressure instead of leaking it, and over years a wall that is permanently wet on the outside is a wall that keeps finding new places to fail — as a Gaithersburg house in this series shows.
Sealing the crack buys you the room to fix the cause. It is not the cause.
Why not just the drain
Because the crack was leaking now, and a drain takes days.
This is the part homeowners are rarely told: the right order is usually stop the leak, then remove the source. You seal the wall on the first day, so the basement is dry while the outside work happens, and then you spend the rest of the job making sure the wall never has to hold that water back again.
Companies that only sell one of the two will tell you the one they sell is sufficient. It usually is not.
The two-month gap
The third visit is the honest part of this file.
The crack and the drain were done together. The buried downspout came back around two months later — after a season of real rain had shown where water was still being delivered to the property rather than taken away from it.
There is a version of this job where all three go on the first quote and the number is bigger. There is also a version where you fix what you can prove, watch what happens, and come back for the rest. The second version costs the homeowner less and needs the contractor to still be around in two months.
We would rather be the kind of company that comes back.