Types of gutters
The good news: Gutters come in all shapes, colors, and prices so you can easily find a match for your style of house and budget.
Unfortunately, figuring the right sizes of the gutters and downspouts for your roof involves some head-banging mathematical formulas.
Not to worry. We’re here to guide you on the path to gutter glory. If you’d like to do your own calculations for sizing your gutters, we’ll help you through it.
Basic Types of Gutters
Let’s start with shapes. There are two basic types, and they’re referred to by the shape of their cross section. Both types come in 5- and 6-inch widths.
1. K-style gutters have flat bottoms and backs, and the front side of the gutter usually has a decorative shape, such as a curve or ogee, that mimics crown molding. Many styles are available.
2. Half-round gutters are exactly what the name suggests: half-round tubes. Half-round gutters often are found on older, historic homes.
Half Round Copper
In general, K-style gutters have twice the capacity of their half-round cousins of the same width, and cost up to 50% more per linear foot.
Gutter Material Available
Cost of materials if you DIY: $2 to 3 per linear foot (6-inch K-style) including downspouts
Cost of pro install (materials and labor): $4 to $9 per linear foot
Cost of pro install (materials and labor): $12 to $25 per linear foot (6-inch K-style)
Seamless (or continuous) gutters are made at the job site. A truck with a spool of flat aluminum pulls up to your home, and the fabricator uses a gutter-forming machine to custom make whatever gutter length is required. There’s no hauling of long gutters. About 70% of all gutter installations are the seamless type.
Installing seamless gutters:
Cost of pro install (fabrication and materials): $5 to $11 per linear foot (6-inch K-style)
Cost of DIY materials, including downspouts: $4 to $6 per linear foot (6-inch K-style)
Cost of pro install (materials and labor): $8 to $10 per linear foot
Cost of DIY materials, including downspouts: $1 to $2 per linear foot (6-inch K-style)
Cost of pro install (materials and labor): $3 to $5 per linear foot
Cost of pro install (materials and labor): $10 to $24 per linear foot, 6-inch half-round (K-style not available in zinc)
Downspouts come as either round or square, in widths from 3 to 6 inches. The most common sizes are rectangular:
Decorative varieties, such as spiral shapes, are available.
The size and number of downspouts you’ll need depends on the capacity of your system.
Rule of thumb: You need one downspout for about every 30 to 40 linear feet of gutter. To increase the capacity of your gutter system, add more downspouts.
How Much Gutter Do You Need?
Figuring gutters sizes and capacities is a complex brain-freeze equation involving the size and slope of your roof and the average maximum rainfall your area can expect. We recommend leaving the calculations to your gutter installation professional.
For the most part, you won’t go wrong with a 5-inch, K-style gutter. “A 5-inch gutter is pretty standard and will handle rainfall just about anywhere in the country,” says Bill Sheetz, owner of Lake Cook Exteriors in Palatine, Ill. He uses them on “almost all our installations.” And he specs oversized (3-inch-by-4-inch) downspouts to ensure good drainage.
Sheetz says a 6-inch gutter has almost twice the capacity of a 5-inch, but cautions that in cold climates, larger gutters run the risk of getting weighted down with ice that could damage the gutter system. Moving to a 6-inch gutter increases costs by about 25%.
For those of you who are self-reliant DIYers determined to do the calculations, these step-by-step instructions will take you through the process.
Or try this online gutter and downspout calculator.