Copper Half-Round 6" Gutter — Sizing & Cost Guide

Copper Half-Round 6" Specifications

Available Materials

Maximum Roof Area by Rainfall Intensity

The table below shows the maximum effective roof area (in square feet) that the Copper Half-Round 6" gutter can drain at various rainfall intensities. The capacity of 7,200 square feet is rated at 1 inch per hour. At higher rainfall intensities, the maximum serviceable roof area decreases proportionally because more water enters the gutter per unit of roof area. Use your local rainfall intensity (available on the states page) to determine if this profile is adequate for your home.

Cost Estimate for Copper Half-Round 6"

The cost of Copper Half-Round 6" gutters ranges from $35 to $55 per linear foot for materials. This price range reflects variations in material thickness, finish options, and regional availability. Professional installation typically adds $3 to $8 per linear foot depending on the height of the building, accessibility, and local labor rates. The table below shows estimated material costs for common gutter run lengths. Total installed cost including downspouts, hangers, end caps, and labor is typically 2 to 3 times the material cost.

half-round Profile Details

Half-round gutters have a classic semicircular cross-section that has been used on buildings for centuries. The smooth curved interior is inherently self-cleaning, as debris tends to wash through rather than getting trapped in corners. Half-round profiles are the preferred choice for historic homes, Craftsman architecture, and Mediterranean-style buildings. They require specialized mounting brackets that wrap around the gutter and attach to the fascia or rafter tails, rather than the hidden hangers used with K-style gutters.

When selecting the Copper Half-Round 6" gutter for your project, consider the total effective roof area draining to the gutter system, the local rainfall intensity for your area, and the number and placement of downspouts. A general rule is to keep the capacity utilization below 75 percent of the rated maximum to provide a safety margin for storms that exceed the design intensity. For homes in areas with frequent heavy rainfall or large roof areas, upgrading to the next larger size within the same style family is a worthwhile investment that adds minimal cost but significantly reduces the risk of overflow during extreme weather events.

Proper installation is critical to gutter performance regardless of the profile selected. Gutters should be sloped toward the downspouts at a rate of approximately 1/16 inch per foot to ensure water flows to the outlets rather than pooling in the gutter. Hanger or bracket spacing should not exceed 36 inches, and many professionals recommend 24-inch spacing for durability and to prevent sagging under water and ice loads. All joints, end caps, and corners should be sealed with high-quality gutter sealant, and downspout connections should be secured with rivets and sealed to prevent leaks at the transitions.

State Compatibility for a Typical 2,000 sq ft Home

For a typical 2,000 square foot home with a 4/12 roof pitch (effective area of approximately 2,100 sq ft), the Copper Half-Round 6" gutter is adequate in 44 states and insufficient in 7 states based on the 1-hour, 10-year storm rainfall intensity. States where this profile is adequate are shown in green; states requiring a larger gutter are shown in red. For borderline cases, adding more downspouts or upgrading to the next size provides an appropriate safety margin.

Downspouts and Outlets for Copper Half-Round 6"

Downspouts are sized to the roof they drain, not to the gutter profile. Fine Homebuilding's rule is 100 sq ft of roof per square inch of downspout at 1 in/hr (600 sq ft for a 2x3, 1,200 for a 3x4), divided by local intensity. The table runs that rule for the six reference roof sizes at a 4/12 pitch and the median state design intensity of 2.6 in/hr, alongside whether the Copper Half-Round 6" itself has the capacity for each roof. A 3x4 outlet is the natural fit for a 6-inch bottom; SMACNA's sizing notes do not allow a downspout wider than the gutter bottom.

Run Length Details for Copper Half-Round 6"

Three numbers follow from the length of each continuous run. Hanger count assumes one every 24 inches plus one at the end (36 inches is the usual maximum). Drop is the total fall from the high end to the outlet at 1/16 inch per foot, with Fine Homebuilding's steeper 1/8 inch per foot shown beside it. Movement is how much the run lengthens between a winter night and a sun-heated summer afternoon, a 100 °F swing, for each material this profile comes in; sealed joints and end caps have to absorb it, and long runs get an expansion joint or a second outlet.

Other Gutter Profiles

Compare the Copper Half-Round 6" with other gutter profiles to find the best match for your project. Each profile offers different trade-offs in capacity, appearance, cost, and material availability.

How This Guide Works

• Capacity is the effective roof area the profile drains at 1 in/hr (5" K-style 5,520 sq ft and 6" K-style 7,960 sq ft are the published figures; half-round, box and fascia values follow manufacturer data). Divide by your intensity and pitch factor for the footprint it serves.
• The median state design intensity used in the tables is 2.6 in/hr, a statewide 1-hour, 10-year value. SMACNA and Fine Homebuilding size to the 5-minute, 10-year burst, which is higher, so a contractor's design tends to be one size larger.
• Downspout counts: 100 sq ft of roof per square inch of downspout at 1 in/hr, scaled to intensity. Hangers at 24 inches; slope 1/16 inch per foot. Thermal movement uses Engineering ToolBox expansion coefficients (copper 16.4 x 10^-6 per °C).
• Prices are national material estimates per linear foot; installation, downspouts, hangers and sealant are extra.
• Sources: Fine Homebuilding #125, Sizing Gutter Systems (capacity and downspout rules); This Old House, How To Size Gutters and Downspouts (pitch-factor table, downspout spacing); the SMACNA Downspout & Gutter Sizing Calculator, built on the Architectural Sheet Metal Manual; NOAA's Precipitation Frequency Data Server (Atlas 14) for point rainfall intensities.

Frequently Asked Questions