TINHORN CULVERT CORRUGATED PIPE PLASTIC STEEL INSTALLATION

Your culvert project will go a lot smoother whether you DIY or hire a contractor if you take a little time to arm yourself with some basic information.
A “minor” Education on the subject of culvert and proper installation can save “major” potential cost of time, money and heartache. 1. TYPE– When selecting your culvert there are several factors to consider, such as type of material.
A. Steel galvanized, known as corrugated metal pipe, or “cmp”.
1. cmp is available from 6″ Dia. up to 120″.
2. cmp culvert is designed for use as “culvert” so there is no need to worry about thickness or gauge. They are made to standardized specs.
3. Sizes and the coatings available on culvert larger than 120″ are available for:
3.a. Bridges, Tunnels, Bunkers, Custom applications, etc.
3.b. A variety of culvert materials and finishes for these extra large applications such as, aluminum, galvanized steel, fiberglass, and epoxy coatings, etc.
4. Galvanized steel culvert does not do well in corrosive environments, saltwater especially.
B. Plastic culvert is available in 2 types:
1. Polyethylene culvert “HDPE” (black) aka n-12, double wall.
1.a. N-12 culvert is the most commonly used for residential, farm, and construction purposes, such as entryways, driveways, pond overflow, storm water drainage, treehouse slides, extreme sports events, etc.
1.b. N-12 culvert is double walled with a smooth inside and ribbed outside.
1.c. N-12 culvert is available in size from 4″ up to 60″ dia., standard length is 20′. 1.d. N-12 culvert is designed with 2 end options, 1st. the plain end, 2nd. the bell coupler on one end and a nipple (spigot) and rubber seal on the other end, designed to be connected together to provide a “weathertight seal”.
2. Polypropylene (gray) “HDPP” is the 2nd type of plastic pipe, pe is gray in color and is a heavy duty version of n-12, it is typically used by municipalities, and on government projects.
2. SIZE– When selecting the size of your culvert there are several sizing factors to consider, diameter, length and height.
A. Flow– How much flow do you need? Flow is related to diameter.
1. For example on a new culvert installation for a driveway entrance, are you up or down hill from the neighbor?
1.a. If uphill use the same size culvert or 1 size smaller.
1.b. If downhill use minimum same size culvert or 1 size bigger.
1.c. Flow is different for different types of culvert materials. (see flow chart)
B. Length– How far off the street is the ditch?
1. The closer to the street the longer the pipe will need to be in order to make the shorter radius turn.
2. Will you be pulling a trailer, or long wheelbase vehicle, r.v., boat, equipment trailer, etc., making sure your crossing is long enough to start with in the beginning, is easier than trying to make it longer later.
C. HEIGHT– How much ditch space?
1. Depth of ditch,
2. Outside diameter of culvert pipe.
3. Depth of gravel to cover pipe, it must be properly covered and packed.