Gutter Downspout Laws
Over 90 percent of the water infiltration issues that affect homes are due to improper drainage, according to the National Association of Certified Home inspectors (NACHI).
Many of the drainage issues that occur can be corrected by diverting the water runoff from the roof of a home into a properly installed gutter system, with proper downspouts and leader extensions to allow water to flow away from the foundation.
Gutters can be made out of any sturdy material that does not contain lead, mercury or any volatile chemicals, either through off-gassing or carried by water, that will have a negative effect on the natural environment. Most gutters are made of aluminum, galvanized steel and PVC. The gutters must be attached to the house with a pitch of 1/4 inch every 4 feet, going to at least one downspout every 35 feet. Proper house attachment is made by installing hanging brackets that clip onto the front and back of the gutters on the top portion, leading to a strap piece that is secured to the roof with nails. The supports must be installed a minimum of every 4 feet and must be installed directly into the roof framing structure.
Downspout neck pieces are required to be attached to the gutter flange with sheet metal screws that hold the downspout to the gutter. The downspout is required to be attached to the house every 6 feet with an appropriately sized downspout mounting bracket, attached with galvanized screws. Downspouts have a flared end that should always point in the direction of the water flow, to prevent leaking at elbow and neck seams.
Leaders are not required to to be mechanically attached to the downspout, but they may be if they are foldaway leaders, meaning you can flip them up when mowing or performing other yard maintenance. The leaders should be a minimum of 4 feet long to move water away from the foundation.
Silicon sealant is the only caulking product approved for sealing and adhesion of gutter joints. Gutters must be sealed at all joints and ends.