Installation

Are Gutters Necessary on a House? A Wall-by-Wall Answer

By Portland Gutter Works · November 4, 2026 · 8 min read

Are gutters necessary on a house in Portland? For most walls, yes — but not for every wall. Walk any block in Woodstock or Kenton and you will find one house with a bare eave on the back. Sometimes a previous owner pulled a rusted gutter off and never replaced it. Sometimes an addition went up without one. Sometimes a garage never had one at all. The question usually comes up in November, when the trench under that eave has turned to mud.

The honest answer is that it depends on the wall, not the house. Here is how to sort it.

What a house without gutters does in Portland weather

Rain that falls on a roof plane has to land somewhere. Without a gutter it lands in a line about a foot out from the wall, 43 inches of it a year, most of it between October and May. On that line three things happen.

• The soil erodes into a trench. Bark dust washes out first, then the topsoil. On the east side's gravelly Missoula-flood silt the trench drains; on the west side's Portland Hills silt and the clay in Beaverton it holds water like a gutter of its own.
• Splash climbs the wall. Drops hitting the trench throw mud and water 18 to 24 inches up the siding. On painted lap siding that means peeling paint within a few winters. On cedar shingle siding it is a black stain that will not wash off.
• The soil beside the foundation stays saturated. This is the one that costs money. A foot from the wall is inside the zone where water works down against the foundation, and on a 1920s basement house that is the whole problem.

Walls that can honestly skip a gutter

A detached shed or garage with nothing beside it. If the roof drips onto gravel or lawn that slopes away, with no basement below, no walkway under the eave and no neighbor's fence within 3 feet, a gutter is optional. Put down a strip of drain rock so the drip line does not become a mud trench and leave it.

Eaves 3 feet or deeper over a slab. Some mid-century ranches in Eastmoreland and Garden Home have overhangs deep enough that the drip line is well away from the wall, over ground that drains. Those eaves work as designed. The test is simple: no mud on the siding, no trench, no damp on the slab edge.

Metal or shake roof planes over a rock drip trench. A deliberately built gravel trench with a perforated pipe underneath — sometimes called a French drain at the drip line — is a real alternative to a gutter on a low outbuilding. It costs about what a gutter does and needs the same cleaning, so building one from scratch rarely makes sense, but an existing one that drains is fine.

Are gutters necessary on a house? Walls that need one

Any wall over a basement or crawl space. Full stop. Wet basements in Laurelhurst, Irvington and Sellwood very often trace back to water getting into the ground within a few feet of the wall, and a gutterless eave puts it there on every rainy day. The post on downspouts and basements covers what happens next.

A wall with a door, walkway or porch under it. The drip line becomes an ice patch in the Gorge east-wind week and a moss patch the rest of the year.

A wall facing a neighbor within 5 feet. On the narrow lots in Alberta, Concordia and St. Johns the drip line is close to the property line. Water that erodes your neighbor's foundation becomes your problem in the end.

Any wall with wood siding to within 8 inches of grade. Splash rots the bottom course.

A roof plane that feeds a valley. Valleys concentrate flow; the drip line under one is a firehose in a hard rain.

The quick test

What adding one costs

A new gutter on a wall that never had one costs about the same per foot as a replacement without the tear-off — typically $11 to $18 a foot installed for seamless aluminum in the Portland area. A 30-foot back wall with one 3x4 downspout and a 6-foot extension is roughly $400–$650. A detached garage with gutters on two sides is $600–$1,100. The installation page describes a sound spec, and the cost page has the wider ranges.

The one thing to plan before the gutter goes up is where the downspout will discharge. A gutter that collects a whole roof plane and drops it in one spot beside the foundation is worse than no gutter at all. On a basement house the water needs to get 6 feet out or into a working rain drain, and that line item belongs on the same estimate.

Mistakes when adding a gutter to a bare wall

• No plan for the water. A new run with a downspout that empties onto a splash block beside the wall concentrates the whole roof plane in one spot. Price the extension or drain line on the same estimate.
• Skipping the fascia. An eave that has had no gutter for years has had rain blowing against its fascia the whole time. Ask for a screwdriver check before the gutter goes up, so soft wood is found first.
• Undersizing a valley wall. A plane fed by a valley can overwhelm a small outlet in a downpour. Ask whether a 3x4 downspout or a second outlet belongs on that run.
• Mismatching the house. A K-style run tacked onto a house with half-round on every other wall looks like a patch. Match the profile and color.
• Leaving the trench. Fill and regrade the old drip trench so the ground slopes away from the wall once the gutter is working.

Questions to ask on the estimate

1. What condition is the fascia in along this wall?
2. Where will the downspout end, and is the extension or drain line on this quote?
3. Will the new run match the profile, color and size of the gutters already on the house?
4. Is a gravel drip trench a reasonable option here instead, and why or why not?
5. How long will the job take, and does it need a second visit for sealant?

Comparing two quotes

Put the quotes side by side and check the same few lines on each: gauge, hanger type and spacing, downspout size, where the water ends up, and any fascia work. At $11 to $18 a foot, a single wall is a small job. The difference between a good quote and a poor one is usually the downspout line, not the per-foot price.

Common questions

Do all houses have gutters?

No. Most Portland houses do, because the rain is long and steady, but plenty of garages, sheds, deep-eaved ranches and some additions have none. Whether that is a problem depends on what sits under the eave, not on what the neighbors have.

Why do some houses not have gutters?

Usually one of three reasons: the overhang is deep enough to throw water clear of the wall, the ground below is rock or gravel that drains, or a gutter rusted off and was never replaced. The first two can be deliberate design. The third is just deferred maintenance.

Do you have to have gutters on a house?

Whether any rule requires them on your house is a question for the city or county permitting office, and an HOA may have its own rules. Practically, any wall over a basement or crawl space, above a door, or close to a neighbor should have one. A shed over gravel usually does not need one.

Why are gutters necessary?

They move roof water away from the three things it damages most: the soil next to the foundation, the bottom of the siding, and anything you walk on under the eave. In a city that gets most of its rain in eight months, that water adds up fast.

Is a gutter on just one wall worth the trip?

Yes, if that wall sits over a basement, a door or a neighbor. Some contractors set a minimum charge for small jobs, so it can make sense to bundle the new run with a cleaning or a repair elsewhere on the house. Ask for a separate price on each line.

The short version

A garage over gravel, a deep eave over a slab that drains, a shed — leave them alone. A wall over a basement, above a door, next to a neighbor, or wearing wood siding — put the gutter on before the rain settles in, and make sure the downspout has somewhere to go. If you are unsure, the honest question to ask yourself is: do I need gutters for my house, or only for these two walls? Often it is the second.