Something that New Jersey home inspectors encounter while performing almost every home inspection is poor grading or surface water controls around the home that they are inspecting. Proper grading and surface water controls are vital in keeping water from collecting close to the exterior foundation walls and ultimately seeping into the basement crawlspace or lower-level. Poor grading can also contribute to conditions that can cause foundation wall cracking and damage. Wet expansive soils freeze and exert hydraulic pressure on a foundation wall and can cause them to crack, bow shift. Almost every home that NJ home inspectors inspect needs some level of improvement to surface water controls and grading.
When a potential homebuyer is looking at a house, he or she needs to be particularly attentive to where that house sits in relation to the exterior grade. Does that house sit higher than the exterior grade allowing water to be directed away or does that house sit lower where water will be directed toward the structure of the home making it more vulnerable to water infiltration problems over time. Of course, a home that sits higher is beneficial but not all homes will sit higher than the grade. In any case the soil around the exterior perimeter must direct water away from the home in order to have the best chance of having a dry basement.
The basic rule of thumb for grading around an exterior of the home is that the grade should slope ¼ inch per foot for the first 6 feet away from the exterior foundation walls. This positive grade will deliver water away from the foundation. Even homes that appear to have a neutral or flat grade need improvement. A neutral grade will also allow water to collect close to the foundation walls.
I find new homeowners spend significant amounts of money on basement water control systems such as basement drains and sump pump. They do this while neglecting the exterior water controls around the home such as re-grading the exterior and controlling water from downspouts and gutters. In fact, much of the basement water infiltration problems that home inspectors in New Jersey see can be greatly reduced if improvements to the grading on the exterior of the home were performed. Making water control improvements on the exterior of the home is much more cost-effective then installing very expensive basement drain systems and sump pumps. The first line of defense is always to control water on the exterior and determine if that helps minimize water seepage in the basement crawlspace or lower level.
It is useful to understand some terminology when it comes to exterior grading. Negative grade is a poor soil grading. The ground slopes toward the dwelling allowing water to be directed to the structure. This is a condition that should be corrected because water can collect along the exterior walls and contribute to water infiltration and foundation and structural problem.
Neutral grade is where the soil around the exterior foundation walls is installed flat without pitch or slope. This condition should also be corrected because water can still collect close to the foundation wall contributing to both water infiltration and foundation wall problems. The soil around this type of grading should be raised to direct water away from the walls.
Positive or correct grading is when the soil around the exterior of the home slopes away from the house one quarter inch per foot for the first 6 feet. This is beneficial to direct water away and help minimize water seepage problems and foundation wall problems. Most homes will need some improvement to the grading.
Grade that has settled or settled grade is when the grade around the exterior of the home in a newer construction was properly sloped when the home was constructed but now has settled creating a negative grade due to the settlement of the backfill around the home. This also requires attention because water will collect close to the exterior foundation walls
Often, home inspectors will inspect the home and find that the exterior siding or structure is very low to the grade. This makes the siding or structure more vulnerable to termites, wood rot and other damages. This is a challenging issue to solve if the home has poor grading. It is challenging to bring more dirt in because if we apply additional soil around the exterior the exterior siding will be partially covered making it even more vulnerable. People buying homes with this type of defect should be aware of the challenges that exist with improving grading around the exterior of the home.
Any discussion about exterior grading goes hand-in-hand with proper operating and pitched downspouts and gutter system. Gutters should remain in good condition and be free flowing at all times so that water does not overflow the gutter. All downspouts should be extended 5 or 6 feet away from the exterior foundation walls in order to avoid collecting water and help minimize water seepage problems and foundation wall damage. Poorly functioning gutters and downspouts are a major contributor to basement water infiltration problems and foundation structural issues. Gutters should be properly sloped and pitched roughly 1/8 of an inch per foot toward their downspouts. Any below ground discharge pipes that the downspouts enter should discharge into a dry well or dispersal field. These below ground pipes must also be made operational. Often below grade downspouts become clogged, obstructed or compressed allowing them not to operate properly. It is imperative that a home have proper exterior grading as well as downspouts and gutter systems that are fully operational. Downspouts and gutters that are fully operational along with proper grading along the exterior foundation walls will be the best first line of defense in keeping water out of the basement, crawlspace or lower-level and also to help prevent structural damage over time.
Here are some simple tips regarding exterior grading.
If you are purchasing a new home, you should expect some settlement of the exterior grade and sometimes this settlement creates a negative slope toward the home. You should address this with your builder before the one-year warranty expires on your new house. Most builders will be accommodating and correct this issue because they understand the importance of having a positive slope around the exterior of the home to avoid water entry
Mulch is very popular in landscaping today. However, to much mulch can be detrimental. Mulch should not used to improve grading. Mulch is used both as a decorative material and it retains water. So, we do not want excessive amounts of mulch close to the exterior walls of the house. If at all possible, try to maintain at least a 6-inch clearance between the start of the structure and the bottom of the wood mulch or grade.
If there is a significant negative slope such as a hill that is directing water toward one or multiple sides of your home then professional corrective measures would be necessary in the form of an exterior drain system, interior drain system, swale or other water control measures. A professional landscaping contractor should be called in to make an assessment and determine the feasibility of installing additional systems of water control
Different soils always impact how well drainage around the home happens. Some soils percolate quickly and drain water very fast. Other soils for instance soils with high amounts of clay content do not percolate as fast and drain water away quickly. The latter is somewhat problematic where the fast-percolating soil is more beneficial at keeping water out of the basement and helping prevent damage to the foundation wall. It is challenging to know when looking at a house what type of soil you have but it is recommended that a purchaser of a home return to the home during heavy rain in order to assess the ability of water to drain around the house.
Water tends to create pathways. So, water collecting in one area of the home or traveling close to the foundation will likely continuing down the same pathway. Unless you do something to correct the issue water will continue to travel these made pathways. It is important to correct these water pathways to help improve drainage around the home
It is important for the New Jersey home inspector to fully inspect the exterior grading around the house as well as the gutters and downspouts. These systems are crucial in helping to minimize water seepage and water infiltration in the basement, crawlspace or level as well as helping to avoid foundation wall movement cracking and damage. It is up to us as NJ home inspectors to educate our clients on what proper drainage around the house that they are buying looks like and give them feedback on how to correct any issues that may exist. Grading issues are frequent and as home inspectors in NJ we have the knowledge and information to share with our clients to make a positive impact on their home buying experience and helping to keep their homes as dry as possible.
John Martino
LookSmart Home Inspections
NJ Home Inspectors Lic # 24GI00058700
Board Certified Master Home Inspector
American Society of Home Inspectors (ACI) #244472
International Association of Certified Home Inspectors (CPI) # 200090933
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5 Preston Ave
East Hanover, NJ 07936
973 407-9621