Rainwater
It is raining; a lot!!!
Where is all that rain going? Hopefully, away from your home!
Managing stormwater is an extremely important task. Ideally, the homebuilder would ensure the homesite has adequate drainage before construction begins, but we do not live in an ideal world! Many homes, new and old, are built with negative grading (land sloping towards the home) and no remedial drainage such as French drains or swales. Many of these homes have their issues compounded by the lack of properly installed roof drainage systems, such as gutters and downspouts.
What happens if stormwater is not directed away from the home?
Water may seem harmless. After all, we are around it every day, we drink it to live, and we are made of it (60% water!!!). But to your home, it is a disaster waiting to happen. According to The National Association of Insurance Commissioners, around 24% of all claims are water-related, and these account for $13 billion in damages each year! Not all claims are related to stormwater, but it is a significant source of damage in many homes. Often, runoff causes slow water intrusion that goes undetected for long periods. These longer periods can complicate the claims process.
Stormwater can enter the home in the following ways
Roof and flashing defects that lead to roof leaks
Siding defects that allow water to penetrate the wall cavity
Water from the roof that is not directed away from the foundation
Improper grading that causes water to pool or seep into the foundation
*The latter two issues will be covered in this article.
Improperly directed runoff can cause slabs to move, basements to leak, and crawlspaces to rot.
This is the reality of stormwater. It can destroy your home's foundation, requiring thousands of dollars in repairs!
Luckily, there are several cost-effective options to choose from that will protect your home!
Yard Drainage
Positive grading
The most basic runoff management system is to have positive grading around your home. This means that the ground slopes away from the house. According to the International Residential Code, the grade should fall at least 6" within the first 10'. (R 401.3) This slope will create adequate drainage away from the home. To achieve positive grading, homes have to be built on mounds or hills, which can be formed by the builders. *Note- adding dirt around a home may work, so long as adequate clearance is left below the siding.
Swales
Positive grading is most easily achieved when the property is built on the highest point of the area. This is not always possible. A possible solution is to use swales. These open ditches redirect water away from the home. Swales are often covered with river rock to help with pooling and increase aesthetics.
French Drains
French drains and other types of surface and perimeter drains are viable alternatives when positive grading cannot be achieved. A slope is only required from the home to the drain. Installing a French drain is rarely a DIY project, but here are the basics to ensure your drain is installed properly.
Installing a French drain
There are many ways to install a French drain. This is one of the most cost-effective and foolproof methods. It works on the following principles: a trench of gravel is sloped around the home to create water flow; within the trench, there is a perforated pipe surrounded by gravel so that water can freely enter. The gravel is encased in a fabric to prevent dirt and debris from entering the pipe. The fabric is surrounded by gravel to prevent the mesh from being prematurely clogged.
A trench is dug around the house.
At least 3' from the home so that the water is not flowing next to the foundation
Minimum of 18" deep
1% slope towards the desired drain location. 1" over 10'. A slightly higher slope ensures drainage
9-12" wide to ensure adequate space for the pipe and gravel
Dig the sides at an angle so that the gravel will stay on the sides
Trenchers can be used to score both sides and the middle is dug out, but mini excavators are better
Cut a minimum 6" trench for the drain pipe
Have your utility lines marked before you dig! I learned the hard way!
The trench is lined with gravel and mesh
Use at least 1" gravel; class a gravel is serviceable, and larger river rock is better.
Place a couple of inches on the bottom and sides
Lay a high-quality non-woven fabric on top of the gravel.
place a couple of inches of gravel on the bottom of the fabric
Install the pipe
Place a perforated minimum 4" drainage pipe onto the gravel
Ensure the pipe is properly sloped; use gravel to raise or lower the pipe
Begin placing gravel around the pipe as you pull the fabric around the pipe
Shoot for 2-3" of gravel between the pipe and the fabric so that the fabric does not clog the pipe
Avoid moving the pipe when laying the gravel.
Once the pipe is encapsulated in the gravel and fabric, fill the trench with gravel; leave the ends open
Connect the perforated pipe to a solid drain pipe
A drain pipe is installed so that it slopes away from the home, either off the property or to a low spot
Pipes should terminate above ground to a lower area; where this is not possible, dry wells may be needed
Dry wells are large holes filled with gravel that collect water until it can seep off
5-gallon buckets with lids and holes are a great way to increase the amount of water these wells can hole
If terminating with a pop-up, dig a small hole around the pop-up and fill it with gravel
Terminating the pipe through a curb hole is a great method in cities, as long as the street has storm drains
Drain pipes should be the same size or larger as the perforated pipe
The drain pipe trench can be filled with dirt
The French drain can be covered with 2" of dirt, but it is best to cover it with stone and work this into the yard's design as the dirt will decrease the effectiveness of the drain and increase the likeliness of a clog.
Never discharge downspouts into perforated French drain pipes. Drain pipes can be shared as long as the area is as large as the French drain and downspout drain pipe.
Roof drainage
Pairing proper yard drainage with roof drainage will protect your home for years to come!
Gutters
Roof drainage starts with gutters. Gutters collect the water that runs off the roof and direct it to downspouts. Gutters should discharge only into downspouts, never onto the roof!!! Seamless gutters look the best, and copper is beautiful, but vinyl and aluminum perform the same function. Gutters should slope towards the downspout at a fall of 1/4"-1/2" per 10', with fasteners every 3'. Gutters should be cleaned regularly.
Downspouts
Downspouts should be the same size as the gutters. There should be downspouts located every 30'-40'. These pipes take the water from the gutters and discharge it below. They may be discharged into lower gutters, onto the ground, or into underground drain pipes. Never discharge downspouts onto the roof, like in the picture on the left. This is a quick way to cause a leak!!!
Splash blocks, extensions, and underground drains
Splash blocks or gutter extensions should discharge water at least 4' from the home's foundation. There is little purpose in having gutters installed if the water is being dumped next to the foundation anyway!! An option for homes with negative grading is underground drains. Solid pipes can be run underground, even in the same trench as a French drain but not in the same pipe. These pipes should have a 1% slope and discharge similar to the French drains listed above.
Disagree?
It is easy to overlook the effects of rainwater. Step outside in a downpour and consider the amount of water landing on your roof, around your home, and in any areas elevated above your foundation. A considerable amount of that water will end up around your foundation!!!
Each home is unique and requires a specific mitigation plan. Qualified gutter and landscape contractors are a good place to start. A home inspector is a great place to go for more information.
Questions? Call, text, or email and I will do my best to point you in the right direction!
Joseph Phelan
(918) 530-6833
jphelan@superiorjoes.com