Negative grading is the culprit why water is flowing into your basement every time it is raining heavily. Today, we’re explaining how to fix negative grading.
If you live in an area where it rains often, tell us – does your basement get filled with water numerous times during spring and/or autumn? If your answer is – yes, then you are probably unaware of the fact that the ground around your home isn’t graded properly. In other words, you are dealing with negative grading.
And, if you don’t fix negative grading as soon as possible, there is a chance that it will be causing you headaches and major monetary losses. To prevent this, you’ll have to add or remove some soil around the house and create a natural slope that will drive away rainwater.
Today, we will be covering several topics, such as what is negative grading, how to fix negative grading, as well as the cost to fix grading around your house so make sure to stick with us ‘till the end of this post.
What Is Negative Grading?
Negative grading points out that the soil around the foundation of your house directs water towards the house. Positive grading, on the other hand, directs water from the structure and protects it. So, when the water is flowing into your home instead of flowing away, this can cause permanent damage if not handled on time.
However, even if the soil around your home drops 1inch/foot and then rises significantly after, let’s say, 4 to 6 feet, then you will still be having a negative grade and the water will somehow find its way into your house.
For instance, if water gets into your basement and sits in there for a while, this can cause discoloration in the walls, make the wooden furniture rot, even pose an electrical hazard, and ruin the isolation and value of your home. Frequent flooding can also cause mold and staying in this room and breathing in mold can cause allergic reactions.
Even worse, water can make even bigger problems and erode soil from beneath your house, cause its foundation to shift, and severely change its structural integrity. Once this happens, floors in your house will start becoming uneven, and drywall will crack.
However, let’s not think about those horrific scenarios right now but focus on the solution.
Grading is all about the angle, which means that you should make some adjustments to your landscape to create an ideal slope and make it easier to drain water away. The ideal slope starts at 1 inch and goes up to 6 inches.
If you want to eliminate puddles around and in your home, keep reading and learn how to fix yard draining issues.
How to Fix Negative Grading? A 5-Step Guide
- Inspect the entire landscape and the soil around the foundation of your house. You will easily notice spots that have drain issues and a negative slope. If there are any plants around, dig them out. Worry not, you will be able to get them back in place soon.
- Remove the layer of grass in width of 6 to 10 inches, then start removing excess soil that prevents the water from pouring off. Use a shovel and a metal rake for this task.
- If you can see that some areas’ grade need to be raised in order to create a slope that makes the water move away from your home, add some soil, then use a lawn roller to pack it down. As a rule of thumb, you should grade 5 to 10 feet around your home’s foundation.
- To make sure you did everything right, use a level and re-check if the slope will actually drive water away.
- Put the plants and grass back in place.
Bonus tip: Does a French drain sound familiar? A French drain is a, simply said, channel that makes it easy for water to drain naturally without causing any damage to your home.
It needs a proper slope that, ideally, descends at a rate of 1% per foot. Using this method, you can solve the negative slope issue but make sure not to make one of these mistakes we’ve explained in another blog.
Which Materials to Use When Fixing Negative Grading?
To fix negative grading, ideally, you will use a mix of clay (just make sure it is not a high clay content soil) and silt. Never use sand to fill in shallow areas around your home since it absorbs water easily, and that is not our goal here.
Also, do not use mulch or use it moderately if you want to increase your grade. Mulch will either hold water or will just filter some of it while most of the water will still go towards your house.
You should also avoid porous materials such as gravel since water can easily find cracks and the path right to your basement. Sure thing, the weeping tile should be covered with some gravel, however, if you put too much of it, you’ll do nothing but overload your drainage system and cause the opposite effect than desired.
Speaking of drains and drainage systems, maybe you’ll want to get more familiar with the newest techniques that can keep clogs and blockages away. One of these methods is called hydro jet drain cleaning.
Once you fix negative grading and decide to re-plant your greenery, make sure not to use gardening mixes that contain much peat. These kinds of mixes absorb water that can, sometime later, end up around the foundation of your home. Ideally, stick to the 1-foot buffer around the foundation and use non-porous materials only to prevent grading from going back to negative.
Cost to Fix Grading Around House…
According to HomeGuide, you will need to pay anywhere between $0.4 and $2 per square foot while removing a slope costs somewhere from $1 to $2. In other words, the cost of fixing grading around the hose goes from $1,000 to $5,000, depending on the size of your backyard and several other factors.
These additional factors include terrain complexity (grading uneven terrains costs more) and location. If your lawn or backyard is rather small, you will probably pay $1,000 maximum.[2]
How to Fix Negative Grading : Final Word
So, we’ve come to the end of today’s journey. We also learned how to fix negative grading, which requires either removing or adding soil around your house’s foundation. The point of doing this is to create a declining grade in order to drive water away from your home.
Michael Davis is a heating & plumbing expert who currently works as independent contractor in SC. He also writes for Plumbertip.
For almost 10 years he worked on various plumbing tasks across South Carolina.
