Some cold-climate builders avoid gutters because of their reputation for getting clogged with ice. The ice bends them, pops their seams, and sometimes pulls them off the house. Yet without gutters, any water not handled at the roof line must be managed on the ground.<br>

Field Guide

Some cold-climate builders avoid gutters because of their reputation for getting clogged with ice. The ice bends them, pops their seams, and sometimes pulls them off the house. Yet without gutters, any water not handled at the roof line must be managed on the ground.

Roofing

Where to Use Gutters

Gutters do the most good in heavy rainfall areas and on buildings with little or no overhang.
Gutters should always be used where houses are built on clay and other frost-susceptible soils (some expansive clays can crack a foundation without freezing; they need only be wet).
Use gutters wherever roof run-off creates a splashback problem that might accelerate the deterioration of entry steps, decks, and siding.
Gutters go a long way toward solving basement water problems. For this reason they are required by code in some places.

Without Gutters

If you don’t use gutters, it’s best to cap the backfill with an impermeable soil layer around the house and slope the grade away from the house at least one inch per foot. Rectangular flagstones laid below the roof’s drip line are another option: they’ll prevent erosion and cause most of the water to splash away from the foundation.

Gutter Installation

Old-style wood and yankee gutters caused a lot of damage because when they leaked, the water backed up into the eaves. This promotes decay in the rafter ends and the soffit. Modern metal and vinyl gutters do a much better job, but there is still the potential for problems if the gutters are not installed with the proper clearances (Gutter Location, below).

Figure: Gutter Location

Place gutters below the roof’s slope-line so that ice and snow can slide by.

In cold climates, the outside edges of all gutters should fall below the roof’s slope line so snow and ice can slide clear. The shallower the roof, the more clearance is needed.

Hanger Types

There are three common hanger types (below). Of these, strap-type hangers that hold the gutter away from the fascia provide the most protection against decay.

Figure: Hanger Types

The “ogee” gutter profile is the most commonly used in residential construction. The hangers shown here are readily available
for the “ogee” gutter. Expansion joints are needed for every 40 ft. (max.) of run.

Installation Details

Aluminum gutter runs should have an expansion joint every 40 ft. of straight run since the gutter will expand and contract 1/8 in. or more over that span.
Gutters should slope at least 1/16 in. per foot of run. It is important to move the water quickly away from the foundation with either a subsurface pipe or splash blocks and by sloping the grade at the surface.
The number of downspouts a roof needs will depend on the size of the conductor pipe. Allow 1 sq. in. of downspout cross-section for every 100 sq. ft. of roof area. Place the downspouts at least 20 ft. apart but no more than 50 ft. apart.