K style is the profile on almost every house in Chicago. Half round is the rounded trough you see on older brick homes, churches and restorations.
They are not two grades of the same thing. They are two different shapes, and the shape decides capacity, price and how the gutter looks from the street.
What a K style gutter is
A K style gutter has a flat back, a flat bottom and a front face with a decorative curve in it. From below, that front profile looks a little like crown molding.
The flat back is the point. It fastens directly against the fascia board with no bracket showing, which makes it faster to fit and cheaper to buy.
It is the default on new construction across the region, in 5 inch and 6 inch widths.
What a half round gutter is
A half round gutter is a semicircular trough. It cannot fasten flat to anything, so it hangs in brackets or on straps fixed to the roof deck.
The look is the reason people ask for it. On a brick bungalow, a Tudor or anything with period detail, a round trough on visible brackets reads as correct. A K style does not.
It is also the older profile. Most houses built before the 1950s had half round before somebody replaced it.
Which one moves more water
K style, at the same nominal width. A flat bottomed trough with a tall back has more cross section than a semicircle of the same opening. It takes more volume before it spills.
That is why a 6 inch K style is our standard on Chicago roofs. The storms here arrive in short heavy bursts, and the trough that fills slowest is the one that does not overflow.
Half round has one drainage advantage worth naming. The curve leaves no corners for debris to pack into, so what does get in moves through instead of building into a plug.
Which one costs more
Half round, and by a clear margin. The trough itself costs more per foot, and the brackets are a separate part that a K style does not need at all.
The fitting takes longer too. Every bracket is set individually, where a K style hanger screws through the back of the trough into the fascia.
Copper half round is the top of the range. That is a specialty material on a specialty profile, and the price reflects both.
Which houses suit half round
Period brick. Tudors, Victorians, older bungalows with detailed eaves, and buildings where the roofline is part of the architecture.
There is a practical case as well as a visual one. Some older homes have no fascia board worth fastening to, and a bracket or strap system solves a problem that a flat backed gutter cannot.
If your house was built after about 1960 and has a plain fascia, K style is the right profile and the cheaper one.
How to tell which you have
Stand under the eave and look at the front edge. A curved decorative face with a flat bottom is K style. A plain half circle is half round.
Then look for brackets. Half round needs something visible fixing it to the roof or the fascia, and K style usually shows nothing but the trough.
Width is a separate question from shape. A 5 inch K style and a 6 inch K style look nearly identical from the ground. That is why the 5 inch against 6 inch question gets asked separately.
What we fit
We fit K style seamless gutters in 5 inch and 6 inch, with 6 inch oversized as our standard. The trough is .032 inch aluminum, formed on site as one continuous piece, with QuickScrew hangers at 24 inch spacing and GeoCel sealed corners.
Gutter apron flashing goes behind every trough, and every install comes with a lifetime warranty on the gutters and on the workmanship.
Read the full spec on our seamless gutters page, or call (866) 488-7776 and we will tell you what your roofline needs.
