The lot grading of a house refers to the level of the ground immediately around the house.
The ground level is graded to determine where water flows during a storm and whether it causes a negative impact on the condition of the foundation and specifically the basement.
This is why there are basically only two types of grading. Positive and negative.
To put it simply positive lot grading means that there area gradual slopes that lead storm water in a direction away from the house. And negative grading means that water flows back to the house instead of being drained away from the house.
The simplest way to identify the lot grading of your house is to observe how rain water flows and where they end up during a storm.
Otherwise, with the lack of rain, the best way to determine grading is to hire a qualified home inspector to do it.
Basement with moisture problems
The biggest problem with poor lot grading is the damage it can do to basements.
No matter how well built a foundational wall is, it can never be completely waterproof. At least not with the current technology and building materials that exists today.
When water ponding occurs, water that collects in the soil immediately outside the building would eventually find it’s way to the foundational walls and potentially make it’s way into it.
Even minor cracks can allow water to seep through. This small issue will slowly grow into a big one if left unattended.
This is why the basement is the area of the house most prone to moisture problems.
In extreme cases, wet basements can cause serious structural problems that affect safety. And if water gets through the basement walls, there can be mold issues that causes health problems.
The good thing is that the workmanship of landed homes are improving all the time with the use of better equipment and materials.
Except for older homes, modern houses these days are pretty sturdy against lot grading problems as long as the problems are not severe.
The idea is simple. As long as water does not get a direct entry into the soil just outside the foundational wall, then it would not be able to make it’s way into the interiors of the house.
Very often, basements with moisture problems can be “healed” or dramatically alleviated by changing from negative grading to positive grading.
Ensure that common problems with gutters and downspouts are eliminated, and that the ground level around the house slopes for about 10 feet away and lower by at least 6 inches at the end.
There is no need to do a major landscaping job. Just use topsoil (blackdirt) purchased from the store to build this artificial landscape.
When you have the undesirable grading problem of having the ground slope towards the house, then you might have to get more professional help to resolve this problem.
Contractors might recommend building a swale to manage this problem.
Erosion can be a big potential problem with ravine lots that have poor grading.
A way to identify this is to investigate the condition of trees and large plants that are found on the slopes.
The best way however, is to consult a professional like a soil engineer.
Don’t think for a moment that erosion would pull a house sitting on top down slopes and into a canyon.
Because before that occurs, a house would probably have already been torn apart be the sheer power of the slowly eroded soil.