Metal or Shingle Roof in the North Cascades Foothills: How Each Handles the Weather

What are the two options, in plain terms?

Asphalt shingles are a mat of fiberglass coated with asphalt and surfaced with mineral granules, laid in overlapping courses. Metal roofing is steel or aluminum in panels, either screwed through the surface or clipped under raised seams. Both can last, and both can fail, depending on installation, details and upkeep.

Shingles shed water by overlap and gravity. Metal sheds it by smooth, continuous panels with sealed seams. The difference matters most at the edges and joints, where each system needs its own flashing and trim.

In the foothills, both are common. Houses along the lower valley tend to carry shingles. Barns, shops and a growing number of upper-valley houses carry metal. The pages on asphalt shingle roofing and metal roofing cover each in depth.

How does each one handle snow?

Metal sheds snow more readily, sometimes all at once, which keeps load off the roof but sends the snow onto whatever sits below. Shingles hold snow longer and release it gradually. Skagit County sets the design snow load by parcel, so ask the county; snow guards can slow a metal roof's slide.

Concrete averages about 18 inches of snow a year by climate tables, and it falls more heavily higher up Highway 20. Many storms start as snow and finish as rain, so the question is often wet, heavy snow rather than depth.

The county publishes snow, wind, seismic and soil design criteria for its parcels on a mapping layer. This guide does not state the zone for any town, because it has not been confirmed. Whoever designs or replaces your roof should check the county's figure for your parcel, particularly for new framing or an addition.

For a metal roof, the main design question is where the snow goes. A slide onto a door, a deck, a parked truck or a gutter is a hazard and a repair bill. Snow guards or retention bars, set above the area to protect, hold snow on the roof so it melts or slides in smaller amounts. Shingles rarely need this, but they can shed ice at the eaves, so the same area deserves thought.

How does each one handle needles, moss and constant damp?

Metal gives moss less to grip and lets needles slide off steeper pitches, though debris at seams and valleys can still hold water. Shingles trap needles and moisture and need regular clearing. Oregon State University Extension says moss holds moisture against roofing and can lift asphalt shingles.

The upper valley gets roughly 70 to 75 inches of precipitation a year, with November the wettest month, and the shade of tall conifers keeps roofs damp. A shingle roof on a shaded north slope may stay wet for months and grow moss in a season or two.

Metal is not immune. Needles collect in valleys and behind chimneys on any roof, and a clogged valley on a metal roof can hold water against seams. But the smooth surface does not give moss the roots it finds in the texture of a shingle, and a steep panel roof tends to clear itself in a storm.

If you choose shingles in a shaded spot, plan for the upkeep: trimming, gutter cleaning and a moss routine. The guide on roof moss in the Skagit Valley covers what works and what to avoid.

What about wind, noise and repair?

Metal needs correct fastening and edge details to resist wind, and rain on bare panels can be loud in uninsulated buildings. Shingles can lift at the edges and are easy to patch. Skagit County's published design wind speed is 85 miles per hour county-wide. Both systems need good installation more than good luck.

Wind comes down the valleys and across open farmland. Long metal panels act like sails if their edges and fasteners are not right, so ask the roofer how the eaves, rakes and ridge will be secured. Shingles depend on sealed tabs and correct nailing, and old shingles with weak seals lift first.

Noise depends on the building. A metal roof over an insulated, finished ceiling is quiet. Over an open barn or shop, rain can be loud. Condensation under metal, in a heated shop for instance, can look like a leak, and needs a ventilation or insulation answer.

Repairs differ in character. A few shingles can be replaced in an hour, and almost any roofer can do it. A damaged metal panel may need a matching panel or a careful patch, and fewer roofers carry standing seam materials.

What does the choice cost, and how do you compare quotes?

Asphalt is the most affordable covering in published Washington cost guides, and metal is generally priced above it, but no sourced price exists for Concrete and none is printed here. Compare quotes by product name, tear-off, flashing, snow guards and ventilation, not by the total alone. The roofer confirms the price in writing.

A fair comparison puts the same roof in front of two or three roofers and asks each to quote both materials. Watch what is included. Metal quotes should name the panel, the gauge, the finish, the trim and any snow retention. Shingle quotes should name the line, the underlayment and the ventilation.

Do not forget the long view. A cheaper roof that needs moss work every year and replacing sooner may cost more over time than a pricier roof that sheds the weather. But no number settles that for your house. The cost guide explains what moves a quote, and the answer for your roof comes from the roofer's inspection.

What changes for a barn, shop or outbuilding?

Outbuildings lean toward metal because the roofs are large and plain, nobody lives underneath and speed of installation counts. The cautions are condensation in heated or occupied buildings, snow sliding onto doors and stock, and fasteners that need checking every few years. Shingles suit small sheds that match the house.

Drive the roads between Lyman, Hamilton and Acme and the pattern is clear: exposed-fastener metal on the barns and shops, shingles on the houses. Long panels cover a big roof in a day or two, and a lifted panel is a simple repair. The washers at each screw are the wear item, and re-fastening a sound roof is often cheaper than replacing it.

Think about what is under the roof. Hay and equipment dislike drips, a heated workshop dislikes condensation, and animals dislike snow sliding from the eave over a door. Say what the building holds when you ask for a quote, and see barn, shop and outbuilding roofing for the practical details.

What should you ask an installer before choosing metal?

How many metal roofs they have installed on houses like yours, which panel and finish they propose, how they handle flashing at chimneys, walls and skylights, how snow will be managed, how the eaves and ridge are secured against wind and how the roof is kept watertight if rain interrupts the job. Their answers should appear in the written scope.

Metal is unforgiving of shortcuts. Dissimilar metals in contact, panels without room to expand, screws driven too tight and flashing improvised with sealant each cause trouble years later. A roofer with real experience will answer these questions without hesitation, and will be glad you asked.

Verify registration with the Washington Department of Labor & Industries, as the registration guide explains, and ask to see a finished local roof if the roofer can arrange it. A neighbor's metal roof that has been through a few winters tells you more than a brochure.

How do you choose for your own building?

Start with the roof: its pitch, the trees over it, what lies under each eave and how you feel about maintenance. A steep roof under tall conifers favors metal. A modest-pitch house with a budget favors shingles with a moss plan. A barn or shop usually favors metal. A roofer who has seen your roof can say which.

Ask each roofer to explain why they recommend what they do, in terms of your roof rather than their preference. A roofer who only installs one material will tend to recommend it, and that is not dishonest, only incomplete. Get a second opinion from someone who works in the other.

Think about the next owner too. Metal can be an attraction in an area where snow and needles are a daily reality, and shingles are familiar to every buyer and inspector. Either is a sound choice if it is installed correctly, ventilated and kept clear.