Water Under My Home?! In Oklahoma?!
Updated: Sep 2
One of the issues we frequently run into as Home Inspectors in Oklahoma, is water intrusion under homes! Unfortunately this is an issue that could easily be avoided if the house was properly set up for the drainage of surface water, the homes “site drainage.”
The site plan should consider a drainage plan that indicates the slope of the surrounding land and drainage patterns that distribute surface waters away from the building site. "For sites that generally provide natural drainage away from the building location, the main concern is establishing an appropriate foundation elevation to maintain drainage immediately adjacent to the foundation.” -(InterNACHI®) Poor site drainage of surface water is probably, the biggest contributor to foundation moisture problems.
Typical slope standards from the homes perimeter is a minimum 6” fall in ground level over a distance of 10ft.
Failure to do this can lead to water intrusion, which can cause damage to the homes HVAC ducting system. We commonly find symptoms of water intrusion inside Air Ducts located under the home, these symptoms include: rusting of metal, the presence of mold (which can lead to all kinds of respiratory related illnesses), sand intrusion, weak air flow, and in sever cases; we have seen the ducts completely filled with water during our Duct Scoping Inspections.
“Surface drainage should be diverted to a storm sewer so as not to create a hazard. Gutters and downspouts are used to direct roof water to the appropriate drainage points.” -InterNACHI