Crawl space specialists · Knoxville, TN
Waterproofing in East Tennessee
Stop water getting in, and move the water that is already there back out.
Waterproofing
Where the water actually goes
Before the individual services below, here is the whole system in one drawing — where the water comes from, where it collects under the house, and what we install to move it back outside.
Crawl space drainage, in cross-section
- Callout 1. The problem: Rain and runoff soak the ground around the house. Downspouts and the fall of the lot decide how much of it arrives.
- Callout 2. The problem: It pushes through the block wall and up through the dirt floor, and the crawl space is the low point it collects in.
- Callout 3. The system: A perforated pipe in a gravel trench around the inside perimeter catches it below the level of the ground you crawl on.
- Callout 4. The system: It runs to a sump basin at the low point, where a pump lifts it out — sized to the water it actually has to move.
- Callout 5. The system: The discharge line is routed far enough from the house that the same water does not simply come back.
Waterproofing
Interior French Drains
The fix when water is already getting in and you need somewhere for it to go.
A perforated pipe is set into a gravel trench around the inside perimeter of the crawl space, below the level of the ground you walk on. Water moving through the soil hits the gravel, drops into the pipe and runs to a low point rather than spreading out across the whole space.
From there it either drains out by gravity, if the lot falls away from the house, or it goes into a sump basin and gets pumped out. Which of those you get depends on your ground, and we work it out on site rather than assuming.
This is the system we reach for most in East Tennessee, because so much of the water here is coming through the soil rather than in through a wall. It handles the water instead of trying to hold it back.
Worth knowing: A drain manages water — it does not stop it arriving. If the real problem is a downspout dumping against the wall, we will tell you to fix that first, because it is cheaper and it may be all you need.
Signs you need this
- Standing water or wet ground after every heavy rain
- A tide line of dried silt around the edge of the crawl space
- Ground that is still damp days after the weather cleared
Waterproofing
Exterior French Drains
Intercepting water in the yard, before it ever reaches the house.
Rather than catching water once it is under the house, an exterior drain catches it in the ground outside. We excavate along the affected side, set perforated pipe in gravel below the problem level, wrap it in filter fabric so silt does not choke it, and run it to daylight or to a dry well.
It is the more disruptive of the two — it means digging in your yard, and it costs more than an interior system. What you get for that is water that never arrives, which matters when the wall itself is the thing getting wet.
We use it where the grade sends water at the house and regrading alone will not fix it, and where staining on the block shows water is coming through the wall rather than up through the ground.
Worth knowing: This one disturbs landscaping, and we would rather you hear that from us at the estimate than discover it on the day. Where an interior system would do the same job, we will say so.
Signs you need this
- Damp block walls, or white chalky staining across them
- A yard that stays soggy long after rain
- Water visibly running toward the house across the lot
Waterproofing
Sump Pump Installation
The low point that water collects in, and the pump that gets it out.
A basin is set into the lowest point of the crawl space and connected to whatever drainage is feeding it. A submersible pump sits inside, switches on when the water reaches a set level, and pushes it out through a discharge line that runs well away from the house.
The discharge line is the part people get wrong. Dumping it three feet from the footing sends the same water straight back where it came from, so we route it properly and make sure it stays clear of the ground it is meant to be protecting.
We size the pump to the space and the water it actually has to move, and fit a check valve so what has been pumped out does not run back down the pipe.
Worth knowing: A pump is a mechanical part and it will eventually fail. If losing it would flood the space, ask us about a battery backup at the estimate — it is not on every job, and it is not always worth it.
Signs you need this
- Water that pools in one corner and sits there
- A crawl space that cannot drain by gravity because the lot is flat or falls toward the house
- An existing basin with no pump, or a pump that never had a proper discharge
Waterproofing
Sump Pump Repair & Replacement
For the pump that runs constantly, or the one that does not run at all.
We check the float switch first, because it is the most common failure and the cheapest to fix. After that: the check valve, the discharge line for blockage or freezing, and whether the basin is silted up to the point the pump cannot draw properly.
A pump that runs constantly is usually not a faulty pump. Nine times in ten it is a stuck float, a failed check valve letting the same water run back down, or a genuine increase in water that means the drainage around it needs looking at.
If the unit is beyond repair we will tell you what a replacement costs before we do anything, and we will tell you if repairing it is the better call.
Worth knowing: If your pump is more than about ten years old, a repair may buy you a season rather than years. We will give you the honest read on repair versus replace rather than defaulting to the bigger job.
Signs you need this
- A pump cycling every few minutes in dry weather
- A pump that is silent when the basin is clearly full
- Rattling, grinding or a burning smell from the basin
Waterproofing
Water Diverters
Sending water somewhere else, usually for a fraction of what a drain costs.
When the water has one obvious source, the cheapest real fix is to send it elsewhere. That can mean extending downspouts well clear of the foundation, setting a surface diverter or swale to turn runoff away, or piping a downspout underground to a discharge point down the slope.
We look at this before we quote drainage, because it is common for a crawl space problem to turn out to be a gutter problem. When that is what is happening, saying so costs us the bigger job and saves you a lot of money.
On sloped East Tennessee lots this is often most of the answer, particularly where the house sits below the driveway or a neighboring property.
Worth knowing: Diverters work on surface water. If the water is moving through the soil rather than across it, this will help but it will not be enough on its own.
Signs you need this
- Water running in from one specific wall or corner
- A downspout discharging right against the foundation
- A driveway or patio that sheds straight at the house
Waterproofing
Grading & Downspouts
Making the ground fall away from the house rather than toward it.
The ground around a house should fall away from it — roughly six inches over the first ten feet. Over the years soil settles, beds get topped up, and that slope quietly reverses until the ground is pitching rain straight back at the foundation.
We re-establish the fall with the right soil, get the gutters and downspouts actually carrying water away, and clear anything that is trapping water against the wall.
It is the least glamorous work we do and often the highest-value. A house whose grading is right has a much easier time staying dry.
Worth knowing: Grading is maintenance as much as a repair — beds get topped up, soil settles again. Expect to keep an eye on it rather than to fix it once forever.
Signs you need this
- Soil that has settled into a dish against the foundation
- Mulch or landscaping beds sitting higher than the crawl space vents
- Gutters overflowing at the same corner every storm
What it costs
Waterproofing price ranges
Guidance, not a quote. Where your job lands depends on the size of the crawl space and what is actually causing the problem — which is what the free estimate is for.
- Interior French drain$2,500 – $7,000
- Exterior French drain$3,000 – $9,000
- Sump pump installation$1,200 – $3,000
- Sump pump repair or replacement$400 – $1,500
- Water diverters, grading & downspouts$500 – $2,500
The rest of the crawl space
Most houses need more than one of these. If you are not sure which, the estimate will tell you — and it is free either way.
Crawl Space Encapsulation
Seal the ground off, then keep the air under there dry for good.
Explore crawl space encapsulationCrawl Space Repair
Fix the framing, the supports and the rot the damp has already cost you.
Explore crawl space repair
We cover 34 towns across 6 East Tennessee counties — see the full service area.
Get your waterproofing estimate
A free on-site estimate takes about an hour, and you get a written price before anyone starts. Monday–Friday, 9am–5pm.