Stop it before the wall
Yard drainage and French drains
Every gallon that is steered away in the yard is one that never tests the foundation. On a sloping lot the house often stands in the path of water coming off the hill behind it, the neighbor's roof and its own gutters. Drainage work changes that path.
Call (205) 555-0115Start with the roof water
A roof sheds a surprising volume in a thunderstorm, and all of it leaves through a handful of downspouts. Where a downspout ends at a splash block by the wall, that corner of the crawl space or basement is usually the wet one.
The fix is to pipe each downspout underground in solid, smooth pipe to a point well down the slope, where it surfaces at a pop-up outlet or opens onto stone. It is the least glamorous drainage job and often the one that makes the difference. Ask for cleanouts so the line can be flushed when it fills with leaves and shingle grit.
Shaping the ground
Soil beside a house settles over the years until it tips toward the wall. Flower beds edged with landscape timbers or stone then hold water there like a basin. Regrading adds compacted soil against the foundation and shapes it to fall away, keeping it below the siding and below any crawl space vents.
Where the whole yard tilts at the house, a swale does the work: a broad, shallow dip in the lawn that catches water coming down the slope and leads it around the building. Done well, it looks like nothing more than a gentle roll in the grass and can be mowed.
French drains
A French drain is a gravel-filled trench with a perforated pipe along the bottom, wrapped in fabric to keep soil out. Water in the ground seeps into the gravel, enters the pipe and runs to an outlet. It suits a soggy strip of lawn or the foot of a bank where water comes out of the ground and not only over it.
It needs fall along its whole length and an outlet lower than its start. Without an outlet it is a buried trough that fills and stays full. Roof water should not be connected into it. Downspouts get their own solid pipe, because a French drain's perforations let that water straight back out beside the house.
Catch basins and channel drains
Where water crosses a hard surface, a grate collects it. A channel drain across the foot of a driveway that slopes to the garage is the common case. A catch basin, a box with a grate on top, takes water from a low spot in the lawn or a patio corner. Both connect to solid pipe leading away, and both need their grates kept clear.
Where the water is allowed to end up
The outlet should be on your own lot, positioned so the flow spreads out and soaks in or reaches a natural drainage path. Aiming a pipe at a neighbor's yard only moves the argument next door.
The gutters, ditches, culverts and pipes along the street are the city's storm sewer. Hoover asks that grass clippings and leaves be kept out of them, and its Public Works Department looks after the ones in the public right-of-way. If your plan involves tying into any of that, ask the city before the trench is dug. The contacts are on the local rules page.
All of this is digging, so Alabama's 811 notice applies: a locate request at least two full working days ahead, and hand tools only close to the marks. Alabama 811's homeowner page has the request form.
Questions for a drainage job
- Where does each pipe start, and where does it come out?
- How much fall is there from one end to the other?
- Is the pipe solid or perforated on each run, and what is it made of?
- Are there cleanouts?
- How will the lawn, beds and any sprinkler lines be put back?
- Who places the 811 request?
Yard drainage questions
Will a French drain dry out my crawl space?
It helps if the water is reaching the wall through the yard on that side. It does nothing about humid air or damp soil under the house. Often it is one part of the answer, with work inside the crawl space as the other.
Do tree roots block the pipes?
They can, particularly perforated pipe near thirsty trees. Fabric wrap and washed stone slow it. Cleanouts make it possible to clear a line without digging it up.
Can I do the downspout lines myself?
Many owners do. Use smooth-walled pipe, keep a steady fall, request the 811 locate first and take the outlet further than feels necessary.
How do I know it worked?
Go out in the next heavy rain and watch the outlets run. Then look under the house or in the basement corner that used to get wet.