Gutters, Downspouts and Drainage for Concrete, WA Homes

Updated August 2026 · Alpine Exteriors · WA contractor license ALPINI751OW

The Short Answer

In Concrete and the upper Skagit Valley, standard five-inch K-style gutters with a single two-by-three downspout are usually undersized for what these roofs actually shed. Homes here generally need six-inch gutters, larger or additional downspouts, guards built for conifer needles rather than broad leaves, and drainage that carries water well past the foundation — because this stretch of Skagit County sees heavier rainfall, more falling fir and cedar debris, and more crawlspace moisture risk than the flatter towns closer to the coast.

The Detail Behind It

Gutter capacity is a function of roof square footage, pitch, and how hard the rain falls, not just what was already on the house. A five-inch gutter paired with a single two-by-three downspout can handle a small, low-pitch roof, but most homes around Concrete have steeper rooflines that shed water faster and concentrate it at fewer points along the eave. When that volume overwhelms an undersized system, water sheets over the gutter face instead of into it, and it lands right where you don't want it — against the siding and down into the foundation soil. On anything but the smallest roof, we generally size up to six-inch gutters with three-by-four downspouts, and we add downspouts rather than relying on one or two to carry an entire elevation. A rough rule of thumb is one downspout for every 600 to 800 square feet of roof area, adjusted for pitch and valleys that funnel extra flow to one spot.

Debris is the other half of the sizing question. Standard leaf guards are designed around broad deciduous leaves and use a mesh or louver gap that lets narrow fir and cedar needles slip straight through, where they mat together and dam the channel. A micro-mesh or reverse-curve guard rated for needle debris performs better here, though no guard eliminates maintenance entirely — needles still collect on top of the guard and in valleys, and someone still needs to clear them once or twice a year.

The crawlspace connection is easy to miss until it's a problem. Many homes in and around Concrete were built with vented crawlspaces, and if downspouts discharge onto a splash block a foot or two from the wall, or simply dump at grade near a foundation vent, that water soaks straight into the soil under the house. Add a wet fall and winter and that soil stays saturated, which raises humidity in the crawlspace, feeds wood rot in framing, and creates conditions for mold. Fixing the gutters and downspouts won't dry out a crawlspace that's already wet, but it stops adding to the problem, which is the necessary first step before anyone deals with vapor barriers or ventilation.

What Makes This Region Different

Concrete sits in the foothills along the Skagit River, close enough to the North Cascades that elevation and terrain change the weather compared with the lowland cities Alpine Exteriors also serves. The broader region has the marine west coast climate typical of Puget Sound and the Washington coast — mild, wet winters and dry-ish summers — but orographic lift, where moist air is forced upward as it hits the foothills, wrings noticeably more rain out of the clouds here than falls in Mount Vernon, Burlington, or Anacortes just a short drive west. Winters also run colder, with occasional snow and light icing at this elevation, which is not something homeowners near the milder coast climate typical of La Conner or Camano Island need to plan around in the same way. An undersized or poorly pitched downspout that freezes mid-storm backs up fast, and ice sitting in a gutter for days adds real weight to the fascia and hangers.

Tree cover is the other big variable. Fir, cedar, and big-leaf maple on steep terrain surround most properties in and around Concrete, and needles drop into gutters nearly year-round rather than in one concentrated autumn window like a maple- or oak-lined street in town. Acreage and rural properties, along with the handful of small commercial and civic buildings in Concrete and nearby communities like Sedro-Woolley, Hamilton, and Birdsview, often have large trees growing close to the roofline with limited flat ground for ladder or lift access, so a gutter job here can mean planning around access before beginning work, not just showing up with a ladder.

It's also worth flagging what doesn't apply here, because Alpine works across a wide service area and the rules aren't the same everywhere. Properties near the water in Island County or along tidal reaches near La Conner can fall under shoreline regulations that govern where and how drainage discharges near the water, and salt air there pushes homeowners toward different gutter materials and fastener choices. None of that governs a job in Concrete, but a homeowner with property in more than one of these areas should know the rules genuinely differ by jurisdiction, and should always verify current local code with the county or city before assuming what worked on one property applies to another.

What the Homeowner Should Actually Do

• Inspect gutters twice a year at minimum — once before the fall storm season ramps up, and again in spring after the heaviest needle drop, rather than waiting for an overflow to notice a problem.
• Have gutters and downspouts sized to the actual roof — square footage, pitch, and valley locations — instead of simply replacing what's there in the same size.
• Choose micro-mesh or reverse-curve guards built for conifer needles over standard leaf-guard products, and still plan on periodic clearing.
• Extend downspouts at least six to ten feet from the foundation, and further on homes with a vented crawlspace, so discharge water isn't soaking directly into the soil under the house.
• Grade soil near the foundation so it slopes away from the house rather than pooling against it.
• Where downspouts currently dump at the surface, consider a tightline drain that carries water underground to daylight or a drywell, rather than letting it sheet across the yard toward the foundation.
• On acreage or commercial and civic properties with large trees close to the roofline, budget access and tree trimming into the maintenance plan, not just the gutter work itself.
• Before installing a drywell or rerouting drainage that could affect a neighboring property or the Skagit River corridor, check with Skagit County or the City of Concrete — permitting can apply, and it's cheaper to ask first than to redo the work.
• Get bids that spell out gutter size, downspout size and count, and guard type in writing, rather than a vague line item that just says "gutters replaced."

Gutters, Downspouts and Drainage FAQ

How big should my gutters and downspouts be for a home in Concrete?

Most homes in and around Concrete are better served by six-inch gutters and three-by-four downspouts rather than the five-inch, two-by-three setup common on smaller or flatter-roofed houses closer to the coast, simply because steeper pitches and heavier local rainfall push more water through the system at once. The right size still depends on your specific roof area, pitch, and how many valleys concentrate flow into one spot, which is why a walk-through beats a generic like-for-like replacement.

Do I need gutter guards, and which kind actually works with fir and cedar needles?

Standard leaf guards are built around wide deciduous leaves and let narrow conifer needles pass through, where they mat up and clog the channel — so a guard is worth adding here, but it should be a micro-mesh or reverse-curve style rated for needle debris. Even a good guard still needs occasional clearing of needles that collect on top or in roof valleys; it reduces maintenance, it doesn't eliminate it.

Can bad gutters and downspouts really cause crawlspace moisture problems?

Yes — a downspout that discharges at the foundation or onto a short splash block sends a concentrated stream of water into the soil right next to a vented crawlspace, and over a wet season that keeps the crawlspace humid, which invites wood rot and mold. Extending downspouts well away from the house and grading soil to drain away from the foundation is one of the most cost-effective steps a homeowner can take, though it addresses new water intrusion, not moisture already trapped inside an existing crawlspace.

Is drainage or downspout work regulated in Skagit County?

Routine gutter and downspout replacement generally doesn't require a permit, but larger drainage changes — drywells, rerouted discharge, or work near the Skagit River corridor or shoreline areas elsewhere in the service area — can fall under county or municipal review. Requirements can change and vary by jurisdiction, so it's worth confirming current rules with Skagit County or the City of Concrete before starting any project beyond a straightforward gutter swap.

Ready to Get Started?

Alpine Exteriors is a licensed Washington contractor (ALPINI751OW) serving Skagit, Island, and Whatcom counties, including Concrete, Mount Vernon, Anacortes, Burlington, Sedro-Woolley, La Conner, Stanwood, Camano Island, and Bellingham. If your gutters are overflowing during heavy rain, clogging with fir or cedar needles, or you're seeing signs of moisture under the house, we'll walk the roofline, size the system to your actual roof and rainfall, and give you a written bid that spells out gutter size, downspout count, and guard type before any work begins.