What a Valley Gutter Does Beside Asphalt

A valley gutter is a shallow paved swale that carries water along the edge of a drive or a lot to an inlet, instead of a tall curb. It has to keep flowing. An overlay that fills the valley creates a pond. Mill or redesign the thickness so the gutter still has slope.

Open free asphalt tonnage calculator →

A shallow swale instead of a tall curb

A valley gutter is a shallow paved channel along the edge of a driveway or a parking lot. Water runs in that dip to an inlet or to the street. You choose it where a tall curb would block doors, carts, or the look of the site, and where you still need to collect water. The shape is a vee or a shallow pan, paved in asphalt or sometimes concrete. The important part is that it keeps flowing. A valley that is flat in the middle is a pond with curbed-looking edges. Ask the quote where the water enters, where it leaves, and what slope is in the flow line. Walk that line after a rain before you accept the work.

An overlay can erase the valley

A uniform overlay spread across a valley gutter fills the low line first. The new surface looks even and the water stops moving. If you resurface, mill the valley or design the new thickness so the gutter still has slope when you are done. Do not fill it with sealer or cold patch to make it look level with the lot. Those products are not a drainage redesign. Ask the crew to mark the flow line before they pave and to check it with a straightedge after. For any new hot mix, plan tons near 145 pounds per cubic foot. If the gutter is 2 feet wide and 80 feet long at 2 inches, that is 160 times 2 divided by 12, times 145, divided by 2,000, about 1.9 tons as a planning estimate for that strip. The plant ticket is the real weight.

Inlets, ice, and the edge of the mat

The valley has to reach an inlet or a daylight point that is lower. An inlet set high is a dam. Ice will occupy the same spot all winter, and that is often the walk people use. Keep the asphalt edge beside the valley at full thickness, not a feather that breaks into the channel and creates a dam of its own. A butt joint against a concrete gutter pan is the same idea: full thickness, clean face, tack as the crew's bond if the quote includes it, not a home spray. If accessible routes cross the valley, check the current ADA Standards and the local official so the pan is not a trip or a slope problem. Drainage and access have to be true at the same time.

A practical sequence

Trace where the valley gutter sends water, and confirm the outlet is lower.
Mill or redesign an overlay so the flow line is not filled flat.
Leave sealer and cold patch out of the channel.
Plan any new asphalt at 145 pounds per cubic foot, with the plant ticket as the real weight.

The mistake to skip

Overlaying a valley gutter flush with the lot and wondering why the aisle holds water.

Questions people ask

What is a valley gutter?

It is a shallow paved swale along the edge of a drive or a lot that carries water to an inlet, used instead of a tall curb. It only works if it keeps sloping. An overlay that fills it makes a pond. If you resurface, mill or design the thickness so the flow line remains. Do not fill the low spot with sealer or cold patch.

How do I count tons in the gutter strip?

Measure the paved width and length of the strip and the compacted inches. A 2 by 80 foot strip at 2 inches is about 1.9 tons at 145 pounds per cubic foot, as a planning estimate. The plant ticket is the real weight. The lot beside the gutter is more area. Filling the valley to save a measuring step removes the drainage you built.

As an Amazon Associate, AsphaltTons.com earns from qualifying purchases. Product links below are sponsored.