Are you wondering whether or not you should have french drains installed on your property?
You’ve come to the right place!
In this Regional Foundation Repair guide, we cover common foundation repair questions, including:
- Why Are French Drains Used?
- Which Types Of Soil Is Ideal For French Drains?
- When Should You Avoid French Drains?
And much more!
The truth is:
There is no definite answer as it depends on the nature of the land you’re working on. However…French drains are (in our opinion) pushed as an end-all-be-all solution in far too many instances.
So…let’s talk about why French drains suck (and when you should avoid them).
Table of Contents
- What Is A French Drain?
- French Drains Don’t Always Work…Here Are Four Reasons Why
- Why French Drains Suck Even If They Work
- So Are French Drains Worth It
It doesn’t take much researching on Google to find out that most sites put French drains on a pedestal when it comes to their basement waterproofing capabilities:
So, it would seem that nearly everyone thinks french drains are amazing… but are they? Or are they actually an over-hyped cash sinkhole? It couldn’t be that companies on the internet recommend them because they’re expensive. Right?
The truth is, French drains are sometimes a decent way to protect your home, but most of the time, they’re a waste of thousands of your hard-earned dollars. Let me explain!
What Is a French Drain?
A French drain is a system for moving water away from your foundation, which doesn’t generally mix well with moisture in the soil. It’s basically a trench dug around your entire home with a large, perforated pipe inside surrounded by crushed gravel.
When water soaks into the ground, it travels more quickly through the large pieces of gravel and drips into the pipe. The pipe is laid at an angle away from your house so that water naturally moves down and away from the concrete foundation.
The pipes are usually wrapped in some kind of filter material — called a geotextile fabric — to stop dirt and other small pieces of debris from fall in. The fabric also stops plant roots from entering the pipe and clogging it (which is surprisingly more common than you think…).
French Drains Don’t Always Work…Here Are Four Reasons Why
French drains can work decently well on some properties, and foundation waterproofing companies around the country push them on homeowners more often than almost any other system for waterproofing.
The problem is, French drains don’t always work! Below are four concrete reasons why they fail to solve your drainage problems.
They Don’t Work in All Types of Soil
Most importantly, French drains won’t work in all parts of the country. There are three types of dirt possible on your property: loose dirt made of sand particles, average dirt made of loam (a mixture of sand, silt, and clay), and compacted, heavy dirt made of clay particles.
Clay soil is dense and doesn’t let water move through it easily, so rain pools around the surface as runoff slowly seeps into the ground.
French drains work best in dirt that drips water into the perforated pipe. Since clay soil absorbs and retains moisture easily, it’s much less likely to release water into the drain than, say, sandy soil.
If you live in an area with clay soil where it rains a lot — like Seattle, New Orleans, Philadelphia, Chicago, or pretty much anywhere in Georgia, to name a few — a French drain is probably a good way to blow a few thousand dollars.
Take a look at this individual who basically wasted $25,000 having a French drain installed that didn’t work because of clay soil:
Even if you have the ideal sandy soil for a French drain, you might still be out of luck if the area is poorly drained. When land is poorly drained, it means the water underground is close to the surface for one reason or another, so rain and melting snow have little room to soak into the ground before it backs up.
If you live on a property that just doesn’t drain well, water will fill your drainpipe because it has nowhere to drain. You now have a very expensive collection tube for standing water that will still damage your foundation.
Check out this review of a French drain installer in an area where poor drainage is common:
French drains that drain into storm basins or other reservoirs are actually illegal in many cities that have a high water table. If the drain continues to route water to the reservoirs, they’ll overflow in record time. In these areas, French drains cause more problems than they solve.
They Require Adequate Slope
The perforated pipe in a French drain needs to be angled downward toward some area where it’s safe to deposit excess water. Usually, this is a storm drain or a low point on a large property.
If the pipe isn’t sloped enough at any point along the line, water will pool in the low section. Naturally, if this is near your foundation, it can cause massive damage.
I was called to a home to repair a bowing foundation wall years ago, and it was determined that an issue with the French drain was the culprit. The water was pooling at a low point in the pipe and overflowing into the soil right next to the basement wall. Whether that was due to poor installation technique or something else, the homeowner ended up paying around $12,000 to stabilize the wall and fix the French drain issue.
Most homeowners won’t experience this kind of problem with their French drain, but even minor pooling can render your costly drain system useless.
They Can Clog
Just like a sink drain or toilet drain in your house, a French drain outside can clog. Most of the time, clogs occur after a few years because the filter material surrounding the drainpipe has too much dirt or plant material in it. In some cases, clogs can happen within a year of installation if the company doing the work doesn’t use the right material — or any filter material at all, which I’ve seen!
Take a look at these examples, which are all too easy to find on the internet!
Even with properly installed systems, it’s not a matter of IF they’ll clog, but a matter of WHEN.
When French drains get blocked, they create the exact problem they were installed to fix, only worse. Rainwater collects in a designated area instead of across an entire side of your house. The soil around where the water flow is blocked becomes saturated with runoff more easily and puts intense pressure on that single point of concrete.
Homeowners can find dangerous cracks in their foundation walls as a result of a French drain clog.
And the worst part? If a French drain wasn’t required in the first place, the homeowner might never have seen any damage if they didn’t install one to begin with.
Unfortunately, clogged French drains happen way more often than most foundation professionals admit.
They Can Easily Become Crushed
The pipe in a French drain is usually a black corrugated pipe made out of plastic. These pipes are super affordable and easy to install because, unlike PVC, they bend readily and don’t need many joints.
After the drainpipe is installed, gravel and dirt are used to backfill over the pipe. Since the drain is made of plastic, there’s a chance it will collapse from the weight during backfilling.
Even if it doesn’t collapse right away, it might over time. People walking over the area can compress the soil enough to crush the pipe, and some equipment — like ride-on lawnmowers or trucks used for other landscaping projects — can easily weigh enough to collapse the line.
Of course, if a French drain gets crushed, it won’t drain as it should. Not only does crushing the pipe make it more likely to get clogged with dirt and plant roots, but it also might stop the water flow and cause pooling. As I mentioned above, pooling water in a French drain can cause localized foundation damage that costs thousands to repair.
But that’s not all…
French drains can be a nightmare if they fail, but they’re still not ideal even if they work as intended.
Why French Drains Suck Even If They Work
Of course, French drains do work pretty well in some areas. However, while many waterproofing companies will push these systems in those cities, we still think they aren’t worth the money.
Even if your French drain works, the systems still suck because:
They’re Unnecessarily Expensive
I’ll be candid here: French drains are absurdly expensive. They require a ton of work and time, mainly because the contractor needs to dig a large trench around your entire property.
When it comes to foundation installation, repair, and waterproofing, excavation is a very costly factor to consider. Most reputable companies won’t use heavy machinery to dig the trench because the weight of the vehicle right next to your house can compress the soil and cause foundation damage. So you’re basically paying for someone to dig a massive trench by hand.
On average, French drains cost around $5,800 to install, and the equipment typically makes up less than $1,500.
If French drains actually worked 100% of the time and solved the drainage issues they’re meant to fix, they’d be worth the money. The problem is, there are a ton of other waterproofing solutions that cost way less and still do a great job of keeping your basement or crawlspace dry.
Waterproofing Options That Are Often Better & Cheaper Than French Drains
Take soil gradation, gutter and leader installation, and a dehumidifier or sump pump inside as a backup. These three things will generally cost under $1,750 total, and in some cases, they’ll do a better job than French drains that cost more than three times as much. Install them yourself, and you’ll get the total under $1,000.
They Ruin Your Yard
Excavation is not only expensive, but it’s also messy. The dirt that comes out of the trench has to go somewhere, and the contractors have no choice but to dump it on your lawn. The soil will sit on your grass for as long as installation takes, so it can die off before the contractors finish the job.
Take this example, which ended up taking the homeowner many hours to prep the lawn and replant grass after French drains were installed:
Not only does the excavation itself damage your landscaping and require some work to get grass to grow back, but French drains are also not so appealing and can detract from your yard’s appearance.
Many French drains are left uncovered, which means you’ll have a long strip of gravel running around your house. This might be fine if you have flower beds that look good with a gravel border, but it can look very strange if you have a deck, patio, or other landscaping feature that the gravel abuts.
Would you like to spend around $6,000 for a water drainage solution that might not work and will make your property look worse? A French drain might be perfect for you!
They Can Actually Damage Your Foundation!
That’s right, homeowners often install French drains to protect their foundation from hydrostatic pressure and water intrusion, but they can actually damage the concrete! Let me explain.
French drains are covered with gravel to catch the water and let it drip into the perforated pipe below. This process works because water is heavy, and the cohesion isn’t strong enough to remain suspended in the large gaps between pieces of gravel.
If you get minimal precipitation, the water will remain suspended in the gravel, won’t drip into the pipe, and will instead gradually seep into the soil around the trench.
Now, if you’ve been paying attention to the problem French drains aim to solve, you’ll already know that this is a big issue!
French drains are supposed to take water out of the soil, not introduce it into the soil.
If you live in an area that gets light rain often instead of heavy rain, a French drain might actually cause more damage to your foundation by increasing the hydrostatic pressure on your concrete.
If a $6,000 installation wasn’t enough for you, maybe the $10,000 horizontal crack repair will be!
French Drains Don’t Last
Now, let’s pretend that French drains work in all types of soil (they don’t), will solve your drainage issues (they might not), and won’t damage your foundation instead of protecting it (they might!). If all those things were true, French drains would be worth it, right?
Even if French drains were as good as many foundation contractors lead you to believe, they’re still a waste of money — and a lot of it — because they don’t last.
The average lifespan of a French drain before it needs expensive service or total replacement is 8-10 years. The geotextile fabric clogs, the pipe gets overrun by tree and plant roots, or the soil moves and gets compressed, causing dips or cracks in the line that render it useless.
That means every decade, you’ll be spending an additional $6,000 to replace your French drain, or at least a few thousand to clear clogs and get new filter fabric installed.
Check out the below quote received to repair just one length of a French drain system:
Definitely not the norm, but you can expect your repair costs to be at least $2,500 in most cases.
At Regional Foundation Repair, we generally suggest a combination of affordable waterproofing techniques to seal the basement or crawlspace and protect your home from water and moisture.
So, When Are French Drains Worth It?
We’ve done a lot of bashing of French drains, mainly because every foundation repair company seems to push them on every homeowner.
The truth is, French drains can be a great option. It just depends on your property, how bad your drainage issue is, and the area in which you live.
French drains are very efficient at relocating water from heavy rain, but only on properties that are adequately drained. That means if you live near a body of water, have shallow groundwater, or your area is designated as a flood zone, a French drain might do nothing for you.
However, if you have sandy or loamy soil, live in an area with good drainage, and frequently experience moderate or heavy rain, a French drain might be the best option. They’re still expensive, they can still ruin your yard, and they’ll still need to be replaced every 8-10 years. However, they’ll relocate water very efficiently if they’re installed correctly.
Couple a French drain with soil gradation, gutters and downspouts, and a dehumidifier inside, and you could rid of your indoor water and humidity issues for good.