How To Fix Negative Grading

Negative grading is more than an inconvenience; it can be destructive to your home when there is heavy rain. If you suffer from negative grading, you can see water seeping through concrete walls in your basement, or your foundations are covered in about an inch of surface water.

Luckily, there are various ways to fix negative grading and put an end to water drainage pooling around your home’s foundation. Water damage to a foundation can be prevented by landscaping around your home and can help avoid costly foundation repairs.

In our guide, you can learn more about how to fix negative slope towards house and keep water away. By the end, you’ll know enough to find the proper method to divert water in your yard and how to fix grading around house, so you remain dry. (Learn How To Level A Concrete Floor That Slopes)

negative grading

How Do You Fix Negative Grades?

Grading is essential for a healthy foundation and yard. Your home’s foundation is based on dirt, and this needs to be graded to keep rainfall from window wells, downspouts, and more away from your home, thus preventing it from seeping into your home and causing damage.

From your foundation walls to the yard, you should have an ideal slope of 6-8 inches fall off to allow rain to drain away from the foundation

Negative vs. Positive Grading

The level of the yard goes into the foundation rather than away from it when it has a negative grade. As a result, water will pool on the foundation, causing issues.

Positive grading drains water away from the house by sloping down from the foundation. Therefore, your yard should have a positive grade to prevent water pooling.

negative slope

How To Fix a Negative Slope in my House?

A negative slope can be corrected by either adding or removing soil. The easiest way is to build soil around the foundation. Then, fill dirt and topsoil along the foundation perimeter.

This allows water to shed away from your home. You can also increase the soil quality so that plants can be used to landscape the region. Some like river stones or gravel substrate, while others prefer plants and shrubs. A positive grade allows plants to grow and water to drain.

How To Raise Soil Around House Foundation?

Raising the soil surrounding your house’s foundation is the quickest fix and comes with the lowest cost to fix negative grading. The process involves filling in the soil surrounding the foundation. 

How to fix a negative grade step by step.

  1. Remove debris from around the foundation of your property. Grass and plants should be dug up before you add new soil.
  2. To raise the level of the foundation, add fill dirt or topsoil. If you’re going to cover the area in gravel afterward, fill dirt is the way to go. If you want to make your planting soil better, use topsoil.
  3. Slope the soil with a tamper. The dirt should travel from the foundation toward your lawn in a positive grade.
  4. Add more soil and rake the slope to have a 6 to 8-inch drop for every 10 feet. To help with your grading, you can use a straight 10 ft 2×4 as your guide.
  5. Once you have your grade, replace grass or plant new plants on the topsoil. You can use river stones or gravel to create a perimeter.

Note: Most often, it says to add soil to get the proper grade. However, it could be you need to remove soil away from your property to get the correct slope, so water flows as it should. (Learn How Long Does Spackle Take To Dry)

positive grading

How Do I Fix The Grade Around My House?

You may require a home inspection to fully understand the situation, especially if purchasing a new home. This home inspection can highlight foundation and negative grading issues before it’s too late.

Why Fix Negative Grading?

The negative grading must be addressed since rain or snowmelt can flood the home or fix puddles in the grass. As stated previously, a 6-inch yard slope every 6 feet is required. The following concerns may arise if you have less than this:

Basement Flooding

If the water runs towards the home, it may enter through the foundation or a basement window. You’ll need to determine if the land grading or another issue is causing the window to leak when it rains.

Basement flooding can lead to rotting wood, electrical issues, and wall discoloration, all leading to a drop in home value.

Mold Growth

When water escapes into the home, mold can grow and cause health risks. You should also prepare yourself with the proper tools to look for mold in the basement. Homes with high humidity can seriously suffer from mold that needs experts to deal with.

Structural Issues

Water pooling around a home can cause foundations to sink. So if you see water pooling, it needs a fix sooner rather than later.

fixing backyard grading

How to Fix Negative Grading

Keep an eye on where the rain water flows in your yard. You can observe where the grading needs to be addressed by watching the rain and where it goes in the yard or goes in the other direction.

You can level the ground by bringing in soil from other parts of your yard and placing this in the lower areas around your home. However, if you have wooden siding, you need to be aware of rot or termites if you backfill with soil, so it touches your wall.

If you lack soil around your home, you can buy topsoil or grading soil, making it easier to level and slope your yard to direct water away from your home. Water can stay at grade level in this type of soil. (Learn How Many Wheelbarrows In A Yard)

Before doing any work, you’ll need to remove any plants and shrubs from these areas of negative drainage.

  1. Remove the grass from the negative drainage area and place it to the side away from the house.
  2. To elevate the grade, add around 8 inches of new soil, which should force water to flow in the opposite direction.
  3. Pack it down using a tamper or a lawn roller until you have the desired 6-inches drop. Add more soil as desired so your yard slopes away from your home by 6 inches at 10 feet. Roll the lawn roller again to deliver a final compaction.
  4. Replace the grass, plants, flower beds and bushes, in the space, you removed in the earlier stages.

How Do I Fix My Backyard Grading?

Water flows downhill and can do so on top of the ground or below the surface. So, there has to be an allowance for water to run away from the building regardless of the type of home, be it on a slab, have a crawl space, basement, or other design.

Proper grading is vital because rainwater from the roof and rainwater that accumulates on the ground surface have to be directed from the home’s foundation.

Home Grading Terms:

  • Positive Grade: Ground surface slopes away from a building.
  • Negative Grade: Ground surface slopes towards the building.
  • Level Grade: The ground surface is level or flat.
  • High Grade or Siding too close to grade: – The ground level is too close to the home’s wood siding and can lead to moisture damage.
  • Settled Grade: Soil is backfilled next to foundation walls and sinks as it settles. The soil grade would be positive when the house is sold, and after a couple of years, it sinks to form a negative grade. You can remedy this by adding additional soil. Often, this takes a home inspector to point out the home needs positive grading work carried out.
  • Siding too close to grade: Correct soil grade leaves a 6-inch minimum clearance from soil and wood siding to stop moisture damage.

Downspouts and gutters can cause many issues without any positive grading in those areas. Proper grading ensures downspout water drainage flows away and not toward the home.

Soil Grading Tips:

  • It’s impossible to tell the soil grade around a home during a home inspection when there’s substantial snow on the ground.
  • After the house is built, most new homes have a significant negative grade. The builder should address the negative grade during the one-year warranty period, but the builder will generally ignore it if the homeowner does not request it.
  • Mulch around the foundation should be avoided because it deceives by promoting what appears to be a positive or suitable downward slope.
  • Individually or in combination, subsurface drainage pipes, swales, French drain, and other techniques may be adequate to make water flow away from the home.
  • Around the foundation, the type of soil or ground cover can significantly impact. Some soils drain like a sieve, while others hold water like a sponge or a pool liner.
  • Unlike gravel or mulch, where water flows straight down, established grass’s root structure creates a barrier that keeps surface water on top of the ground and away from the foundation walls.

How Do I Fix A Negative Slope In My Backyard?

You can prepare the ground for landscaping and plants by grading the yard. In addition, you have several landscaping alternatives.

Water will drain from the grade to the lowest point in all cases; therefore, use plants that thrive in water.

Proper soil preparation will allow water to drain, thus providing your plants with what they need.

If you plan to surround the foundation with gravel or stone, regular fill dirt is acceptable as this can help drain water away from the house. Note: Gutters and downspouts may need a means of passing water beyond the area of your house.

Water will always flow downhill, and if it is toward the house, it seeps into the concrete of your foundation wall. If you have such issues, bare concrete is permeable, and you can seal this with butyl sealants.

If you think adding a sump pump will fix your problems, it will only get rid of the water inside your home. Nothing beats having a proper slope around your home.

You can find other areas where groundwater rises to the surface in crawlspace soil excavations. If left unattended, issues will arise when surface and groundwater drainage systems are not installed.

Vent wells let air in while keeping water out. They should be sealed to the foundation walls and extend above grade to deflect surface water. Wells can be filled with pea gravel where it would absorb water preventing groundwater from rising to the vent mouth.

Misplaced vent wells are widespread. Patios over foundation vents are often built without vent wells. (Learn How Thick Should A Concrete Patio Be)

If a negative slope ends far from the home, a swale can be dug to catch water before it reaches the foundation. Swales are seasonal ponds filled with wetland vegetation that thrive in saturated water. Seasonal droughts are no match for the plants’ ability to thrive year-round.

Swales should have drainage, usually piped to downspout drains. Instead of swales, simple French drains can direct runoff and groundwater into drain lines.

While an appropriate home slope may not be as appealing as other home improvements, it can prevent major and costly problems.

Thorough home inspections can pinpoint many house grading issues and underlying causes. However, slope-related issues don’t go away and should be addressed before things go south.

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