Expansive or swelling soils absorb large amounts of water and expand in volume, causing the ground and structures surrounding the soil to heave. The presence of these soils - also called reactive soils - is not always readily apparent. They can be covered by layers of topsoil or dense vegetation and are not always on the surface.
Expanding soil can make a structure's foundation "float", causing interior and exterior walls to crack and, at worst, the foundation's structural integrity to fail. To protect a foundation on swelling soils, roof drainage must be carried away from the soil closest to the foundation. This prevents the soil from becoming saturated and creating an unstable environment for the foundation.
•The average cost of foundation repair is currently about $6,000+ but can cost tens of thousands
•Homes that are not protected with a properly installed rain removal system are more likely to suffer foundation damage and are less likely to retain their value.
•When selling, homes with foundation problems typically are forced to offer a 20-25% discount for repairs to the foundation.
•Studies show that 70% of homes have improper gutter systems or no gutter systems at all.
•According to foundation repair companies only 50% of homes with foundation failures seek to be repaired.
•Experts all agree that foundation damages left unrepaired will continue to worsen and become more expensive to repair.
•Home buyers attempting to get financing through a FHA or VA loan will have a bad foundation flagged and be unable to obtain financing until repairs are completed.
The International Residential Code (IRC) is a comprehensive, stand-alone residential code that creates minimum regulations for one and two-family dwellings of three stories or less. It brings together all building, plumbing, mechanical, fuel gas, energy and electrical provisions for one- and two-family residences.
•Section R-401.3 of the International Residential Code addresses diversion of surface drainage away from foundation walls.
"...drainage shall be diverted to a storm sewer conveyance or other approved point of collection that does not create a hazard."
•Section R-801.3 of the International Residential Code addresses the requirement of roof drainage in areas known to have expansive and/or collapsible soil:
"In areas where expansive or collapsible soils are known to exist, all dwellings shall have a controlled method of water disposal from roofs that will collect and discharge all roof drainage to the ground surface at least 5' away from the foundation walls or to an approved drainage system."
Experts agree that a quality rainwater diversion system is the most effective way to safeguard your investment from the costs and stress that comes with a damaged foundation.... Is to require all drainage off of a residential roof be collected and discharged onto the exterior grade surface no closer than 5 feet (1524 mm) of the exterior house foundation line on all sides." -Rod V. McCasland, R-Mac Engineering Company, Inc
"It is our opinion that a roof drainage system is required to adequately protect the foundation support system (of a building)..." -Michael T. Scanlon, Norex Engineering, Inc.