Gutter replacement: K-style vs half-round, sizing, gutter guards, and the install details that matter

By Carlos Mendez, Roofing contractor, 22 years · 2026-03-12

Gutters are the most overlooked part of the roof system and the #1 source of foundation and basement water damage when they fail. Sizing, slope, downspout placement, and guard systems all matter — here's how to think about each.

K-style aluminum: $8–$15 per linear foot installed

The standard residential gutter. Matches most aesthetic. Available in steel, aluminum, and copper. Aluminum is the right default — light, corrosion-resistant, holds paint well, 20-year typical life. Steel sags less but rusts; copper costs 3x and lasts 50+ years.

Half-round: $10–$25 per linear foot installed

Historic / craftsman aesthetic. Costs more, available in copper and aluminum. Sheds debris better than K-style (no inside corners). Use case: historic preservation, premium architecture, or wherever you don't want guards but want self-cleaning behavior.

Sizing matters

Standard 5-inch gutters handle ~600 sq ft of roof drainage. For larger or steeper roofs, 6-inch gutters move ~40% more water and prevent overflow during heavy rain. If your gutters routinely overflow even when clean, you need 6-inch.

Gutter guards: $7–$20 per linear foot add

Mesh guards (LeafFilter, Gutter Guard, etc.) reduce cleaning frequency 80–90% but don't eliminate it. They can also cause overflow in heavy rain if the mesh clogs. Best for: properties with overhanging trees and dangerous gutter access. Skip if: you can safely clean your own gutters once or twice a year.

Downspout discharge is half the system

Downspouts must discharge water 4–6 feet from the foundation, ideally to a drain that carries it 10+ feet away. Splash blocks are not enough on clay soil. Foundation cracking and basement leaks are almost always downspout placement issues, not the gutter itself.