Portland, Oregon Gutter Guide for the Long Wet Season

Portland gutters do not usually fail in one dramatic storm. They fail slowly, over a wet season that runs from roughly October to May, when fir needles, moss and shingle grit pack the troughs and steady rain keeps them full for days at a time. The fix for most Portland homes is a cleaning before the heavy rain settles in, a fine-mesh guard where conifers overhang the roof, and downspouts that send water somewhere it can actually soak in or drain away.

Why Portland is hard on gutters

Most cities get rain in bursts. Portland gets it in long, patient stretches. A slow gutter elsewhere dries out between storms. In Portland the same gutter can sit with water in it for most of a week, and that changes what goes wrong.

Needles, not just leaves. Douglas fir, western red cedar and pine shed fine material all year, with heavier drops in fall and after windstorms. Needles are small enough to slip through basic screens and they mat together into a dense layer that holds water like a sponge.

Moss and roof grit. Shaded, damp roofs grow moss, and moss sheds. Older composition roofs also lose granules, and both end up in the gutter, where they settle into a sludge that blocks outlets far more stubbornly than dry leaves do.

Standing water. When the bottom of a gutter is always wet, hangers corrode faster, seams lose their seal sooner and the fascia board behind the gutter stays damp. Rotted fascia is one of the most common things found when old gutters come off a Portland house.

Atmospheric river events. A few times a season, a warm, very wet system can drop a lot of rain in a short window. That is when undersized gutters and clogged downspouts overflow, and when you find out where the water really goes.

A fall checklist for Portland homes

Late October and early November is a good window: most deciduous leaves are down, the heavy rain has not fully arrived, and you can still see problems from the ground on a dry afternoon.

1. Watch it rain. The most useful inspection you can do takes ten minutes during a steady shower. Walk around the house and look for water sheeting over the front edge, dripping from corners and seams, or a downspout that stays dry while the gutter above it overflows. A dry downspout in the rain almost always means a clog at the outlet or in the elbow.
2. Look at the pitch. Gutters should slope gently toward each downspout. If you see water pooling in the middle of a run on a dry day, or a run that dips in the centre, the hangers have loosened or the gutter was hung flat.
3. Check the fascia. Paint peeling behind the gutter, soft spots, or a gutter that pulls away from the house at the top are signs the board behind it is wet or rotting. That needs fixing before new gutters go on, or the new ones will not stay put.
4. Follow every downspout to the end. Where does the water go when it leaves the pipe? Onto a splash block, into a pipe in the ground, onto the driveway, or straight into a planting bed next to the foundation?
5. Note the trees. Which runs sit under conifers? Those runs fill fastest and are where a guard pays off most.

Gutter guards for fir and cedar country

Guards are where Portland homeowners most often spend money on the wrong thing. The short version: for needles, the mesh has to be fine.

• Micro-mesh (stainless steel). A fine stainless mesh over a rigid frame keeps out needles and most roof grit. This is usually the best match for houses under Douglas firs and cedars. It is also the most expensive type, and the top still needs an occasional brush-off, because needles and moss can sit on the surface and slow water down.
• Perforated aluminum or vinyl screens. Fine for broadleaf trees like maples and oaks, but needles slip through the holes and lodge underneath, where they are harder to clean out than an open gutter.
• Reverse-curve (surface tension) guards. These shed leaves well, but in very heavy rain some water can run past the curve, and fine needles and moss can collect at the entry slot.
• Foam and brush inserts. Cheap and easy, but in a wet climate they hold debris and moisture, grow moss of their own and usually need replacing within a few seasons.

No guard ends maintenance under big conifers. A good one cuts the cleaning from a messy scoop-out every few months to a lighter brushing once or twice a year.

Sizing: 5-inch or 6-inch

Many Portland houses still have 5-inch K-style gutters with 2x3 downspouts, and for smaller, simpler roofs that can be enough. Larger roofs, steep pitches, valleys that concentrate water onto one stretch of gutter, and long runs with a single downspout often need 6-inch gutters with 3x4 downspouts. A bigger downspout also clogs less often, which matters in a climate where debris never fully dries out.

Sizing should come from the roof area draining into each run and the pitch, not from what was there before. When replacing gutters, it is worth asking whether an extra downspout on a long run would help more than going up a size. A proper quote should spell out the size, the profile, the metal thickness, the number of downspouts and the hanger spacing.

Where Portland downspouts should drain

Downspouts are the part of the system most people never think about, and in Portland they carry a lot of water over a season.

Many older Portland homes have downspouts that run into a pipe in the ground. That pipe might lead to a drywell, a soakage trench, a storm line or, in some older neighbourhoods, the combined sewer. The city has for years encouraged homeowners to keep roof water out of the sewer where that is possible, and it has rules about how and where water can be released on a property. Before disconnecting, reconnecting or rerouting a downspout that goes underground, check with the City of Portland's Bureau of Environmental Services so the change is allowed and does not send water toward a neighbour.

For downspouts that discharge above ground, the basics are simple:

• Carry the water several feet away from the foundation with an extension or a buried line, not onto a splash block right at the wall.
• Do not empty downspouts onto walkways, steps or a neighbour's lot.
• Make sure the ground slopes away from the house where the water lands.
• If a basement corner gets damp after rain, check the downspout above it first. It is very often the cause.

On hillside lots, common in the West Hills, water released at the top of a slope can erode the ground lower down.

Frequently asked questions

When should gutters be cleaned in Portland?

Most Portland homes do well with a cleaning in late fall, once the leaves are down, and another in late spring after the conifers drop pollen cones and needles. Houses under big firs or cedars may need a third visit in mid-winter.

Are gutter guards worth it under Douglas firs?

A fine stainless micro-mesh guard usually is, because it keeps needles out of the trough where they are hardest to remove. Cheaper screens with larger holes often make things worse under conifers, since needles pass through and get trapped underneath. Expect to brush the surface of any guard once or twice a year.

Why do gutters overflow when they look clean?

The most common cause is a clog at the outlet or in the downspout elbow, which you cannot see from the ground. Other causes are a run pitched the wrong way, a roof valley dumping more water than a 5-inch gutter can carry, or too few downspouts for the length of the run. Watching the gutter during a steady rain usually shows which one it is.

Is a permit needed to change downspouts in Portland?

It depends on what you are changing. Adding an above-ground extension is usually simple, but disconnecting a downspout from an underground pipe or building a new drywell or soakage area can fall under city stormwater rules. Check with the Bureau of Environmental Services before changing anything that goes into the ground.

Getting a quote

If your gutters are overflowing, sagging or full of needles, or you are weighing guards before another wet season, tell us about the house through the quote form. Include the number of storeys, which sides sit under trees, and anything you have noticed during rain. Someone who installs and repairs gutters around Portland then looks at the roofline and puts the work in a written quote. Our Portland page lists the gutter services covered in the area.