Adel Gutter Replacement & Gutter Guard Installation

How gutter size is actually decided

Most homes come from the builder with 5-inch K-style gutter because it is the default, not because someone calculated it. The calculation is not complicated: you take the roof area draining into a given run, adjust for how steep that roof is, and check it against what the gutter can carry. A 5-inch gutter moves a useful amount of water. A 6-inch gutter moves roughly forty percent more, and the outlet at the downspout is larger too, which matters more than the extra width. The reason this comes up so often is that a roof does not drain evenly. One long run at the back of the house may take twice the water of anything at the front, and that single run is where the overflow shows up. Upsizing the whole system when only one elevation is undersized is a waste of money, and matching the original size when the original was wrong just repeats the mistake. Ask any contractor quoting your job what roof area they measured and which runs they sized for. If the answer is that they matched what was already there, they have not done the arithmetic.