The grading of your property is likely not an issue that you’ve spent a lot of time thinking about, but if it’s not done correctly, you are putting yourself at risk of very expensive and extensive damage to your home and property.
What is grading?
In the most simple terms, grading is the slope of your land, which determines where a drop of water will end up. The Rocky Mountains are often called the Great Continental Divide because if a drop of rain falls one inch to the west on the slope of the mountains, it will end up in the Pacific Ocean, and if it falls one inch to the east, it will end up in the Atlantic.
Likewise, if a drop of rain falls on one side of your roof, it may be directed to a safe place, far from your foundation, and if it falls on the other side, bad grading may make it pool right near your home, causing major problems.
Positive vs negative grading
So, the purpose of grading is to get water away from places, especially houses, where it shouldn’t be pooling. A “positive grade” is one that is high and then gradually slopes lower, which is what you want for a home. A negative grade, then, is one that is low then slopes uphill. This would also be “negative” in the sense that water will flow downhill towards the home.
A home should always have a positive grade, being higher than the land directly around it. You will see different recommendations for just how sloped this grade should be, but a good rule of thumb is 1 inch decline for every 1 foot away from the house over the first 10 feet. Others will say that as long as there is a 6-inch slope in the first 10 feet from the house, it has a sufficient positive grade.
How to determine the slope of your grade
It can be very difficult to eyeball your grading, and you will almost certainly not see all of the landscape accurately that way. A more accurate way will be to measure it using two stakes, a string, a level and a tape measure.
To begin with, secure a “string level” onto the string, then tie the string to both stakes with 10 feet of string between them. Then, knock in the first stake near the foundation of the house and the second stake 10 feet away, making sure the string is taut. Knock the first stake in until the string just touches the ground, and knock in the other stake until the string level reads level.
Measure the distance between the ground and the string on the second stake. If there are fewer than 6 inches (and hopefully more) between the ground and the string, you do not have sufficient positive grading. Re-run this test around the entire home to see how different sides of the structure measure up.
What to do if you have insufficient grading?
While you are unlikely to have a negative grade around your home, minor positive grades — like a 3- or 4-inch slope over 10 feet — are not enough to protect your foundation. This is because they are nearly flat and cannot direct moisture away quickly and efficiently enough.
Fixing this, in theory, is as simple as taking away dirt from the high points away from the house and bringing that dirt up close to the foundation to increase the slope. Before you just start digging and bringing dirt towards your foundation, there are two major warnings.
First, digging should not be done until you have had the local utilities come out and mark the location of any water, sewer, electricity, gas or other lines under your lawn. Skipping this may seem like no big deal, but people frequently incur serious injury or death when hitting these hidden dangers underground.
Second, do not stack dirt near your foundation if it exceeds 6 inches (some say 8 or even 10 inches) from the beginning of your siding. Another way of saying that is that at least 6 inches of your foundation should remain visible.
It is common for people to “fix” their grading by piling up dirt next to their homes and then covering up the entire foundation and even some siding. This can rot the wooden sill between the foundation and the home’s framing, introduce termites or carpenter ants into your home, bring mold and mildew to the siding and many other problems. You’re actually creating the exact problem (moisture) that you were trying to prevent.
Need help? Call Anthony’s at (812) 345-5694
Though it seems simple, grading can often get complicated. Larger properties even need to create “grading plans” that are approved by a civil engineer to make sure all water is being directed to an approved stormwater drainage system. It can also be back-breaking work to change the slope of an entire area of a property — often one shovel-full at a time.
There is no shame in calling for help from an expert. And in Bloomington, Indiana, Anthony’s Lawn and Landscaping is a trusted local company with years of experience.
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