When planning a new home, drainage probably isn’t the first thing anybody gets excited about.
Nobody sits down with a builder and says the dream has always been a properly graded backyard with strategically managed stormwater runoff.
The kitchen gets attention. The master bathroom gets attention. Flooring, cabinets, countertops and light fixtures can generate hours of discussion.
Drainage?
Drainage usually becomes interesting when it doesn’t work.
I’m Elwin Ordoyne, Vice President of E.C.O. Builders Inc. in Slidell, Louisiana, and residential construction in South Louisiana comes with one unavoidable reality: rain is going to happen. Sometimes a little. Sometimes enough to make somebody start checking whether the neighborhood has an ark-building permit.
That’s why drainage planning needs to begin before residential construction, not after the house is finished and the first serious thunderstorm arrives.
Water Was Already Going Somewhere
Before construction begins, rainwater already has a pattern across the property.
Water hits the ground, some absorbs into the soil and the rest follows elevation toward lower areas.
Then construction begins.
- A house gets built.
- A driveway goes in.
- Sidewalks are added.
Maybe there’s a patio, outdoor kitchen or pool.
Suddenly, thousands of square feet that once absorbed rainfall have been covered by roofs and hard surfaces.
The water hasn’t disappeared.
It simply has new places to go.
Figuring out where those places should be is the purpose of drainage planning.
Water Is Surprisingly Good at Finding the Lowest Spot
Gravity has been around considerably longer than the construction industry, and so far nobody has successfully negotiated with it.
Water travels downhill.
That sounds painfully obvious, but residential properties can have subtle elevation changes that aren’t immediately noticeable when standing in the yard.
A few inches can matter.
That’s why lot elevations need to be considered before construction begins. The finished floor elevation of the house, surrounding yard, neighboring properties, street and existing drainage infrastructure all contribute to how water moves.
In relatively flat areas around Slidell and throughout South Louisiana, water may not have much slope available to help it along.
That makes planning even more important.
The Roof Changes Everything
Consider the size of a typical residential roof.
During a heavy rain, that roof collects a substantial amount of water.
Before the house existed, rain fell across the property and was distributed over the ground. After construction, the roof gathers rainfall across a large area and redirects it toward specific locations.
That might be gutters.
It might be downspouts.
It might simply be the roofline dumping water onto the ground.
Either way, the water becomes concentrated.
If downspouts discharge into the wrong locations, water can accumulate near the foundation or create consistently wet areas around the house.
Planning where roof runoff will go before construction is considerably easier than discovering the problem after landscaping is installed.
Concrete Doesn’t Absorb Much Water
This will probably not come as breaking news, but driveways aren’t particularly thirsty.
Neither are patios, sidewalks or pool decks.
These surfaces prevent water from soaking into the ground and instead direct it somewhere else.
The slope of a driveway can therefore become part of the drainage system whether anybody intended that to happen or not.
The same applies to patios and walkways.
A driveway directing water toward the garage is obviously something worth identifying before concrete is poured. A patio that sends water toward the house creates a similar concern.
Once concrete is installed, changing elevations becomes a much more complicated conversation.
Before concrete is installed, it’s planning.
Afterward, it’s demolition.
Planning is generally the more pleasant option.
Soil Matters Too
Drainage isn’t determined entirely by what can be seen above ground.
Soil conditions affect how quickly water can be absorbed.
Some soils drain relatively well. Others hold water longer. Construction itself can also change how soil behaves.
Heavy equipment moves across the property. Fill material may be added. Areas become compacted.
That means the drainage characteristics of the finished property may be different from those of the original lot.
Proper grading can help account for those conditions and establish predictable routes for surface water.
Depending on the property, additional drainage components may also be appropriate.
These can include swales, catch basins, underground piping or other methods designed around the specific site.
There isn’t one universal drainage system that belongs on every house.
The property determines the solution.
The Neighbor’s Yard Matters
Drainage planning can’t happen in a vacuum.
Water doesn’t recognize property lines.
Unfortunately, neighbors do.
Changing the elevation of a property can potentially change where water travels. That makes surrounding properties part of the drainage conversation.
Existing homes, yards, fences, ditches, streets and drainage systems all provide clues about how water moves through the area.
A residential construction project needs to consider those conditions rather than simply concentrating on moving water away from the new house as quickly as possible.
Sending the problem next door isn’t exactly a drainage plan.
It’s more like a future conversation nobody wants to have.
Fixing Drainage Later Can Get Complicated
Most drainage problems can be addressed somehow.
The question is how much work will be involved.
After construction, there may be landscaping, fences, irrigation systems, driveways, sidewalks and patios standing between the problem and the solution.
Suddenly, installing drainage might require removing plants, cutting concrete or digging through finished portions of the property.
That’s why drainage belongs in the early planning process.
It allows elevations and water movement to be considered alongside the house, driveway, landscaping and other improvements.
Plan for the Rain Before the Rain Arrives
Building a house involves hundreds of decisions.
Some are visible every day.
Others quietly do their jobs in the background.
Drainage falls into the second category.
Nobody walks into a beautifully finished home and immediately compliments the direction of surface runoff.
That’s probably a good thing.
Proper drainage isn’t supposed to be exciting.
It’s supposed to work.
- And in South Louisiana, where the weather occasionally decides to dump a swimming pool’s worth of water out of the sky before lunch, figuring out where that water is going before construction begins makes a lot more sense than figuring it out afterward.
