Ferndale Siding Composite Decking Built for Marietta's Waterfront Exposure
Marietta sits on the water side of Ferndale, close enough to Lummi Bay that salt-laden air, driving rain, and a moss season that barely lets up are just part of owning a home here. A deck built in this part of Whatcom County lives outside in exactly those conditions year-round, with no wall or roofline to take the edge off. What holds up fine on a covered porch or a drier inland lot can start showing real wear on a Marietta deck within a few wet seasons if the material and build details aren't matched to what this specific stretch of coastline actually does to outdoor wood and hardware.
Composite decking exists specifically to handle that kind of exposure better than solid wood does, but the category covers a wide range of quality and construction, and "composite" on a spec sheet doesn't tell you much about how a board will actually perform two bay-facing winters from now. This page covers what a Marietta deck needs from its decking material, what a correct composite installation involves here, and how our process works for this specific stretch of Ferndale.
What Marietta's Climate Does to a Deck
Salt Air Off Lummi Bay
Homes close to Lummi Bay take a steadier dose of salt-laden air than towns set further inland in Whatcom County, and a deck sits directly in it with nothing overhead to block the exposure. Salt accelerates corrosion in any exposed metal on a deck: fasteners, brackets, railing hardware, post connectors, and a fastener that's begun corroding loses holding strength well before it looks obviously bad. On a structure people walk and stand on every day, that's a structural concern, not a cosmetic one.
Driving Rain and Wind
Storms coming off the water in this part of Ferndale rarely fall straight down. Wind pushes rain sideways, driving it up under railings, into ledger connections, and between deck boards that aren't gapped the right way. A deck surface that sheds water fine on a calm, dry day can still trap moisture the moment wind gets involved, and around Marietta, wind gets involved often.
A Moss Season That Runs Most of the Year
Mild temperatures and near-constant moisture give moss and mildew a long growing season across Whatcom County, and horizontal deck surfaces are usually among the first places it takes hold: they hold water longer than a vertical wall and stay damp between rain events. Shaded decks and north-facing surfaces tend to show it first, and any decking material with even a little surface porosity gives moss something to grip onto.
What "Composite Decking" Actually Means
Composite decking is generally a blend of wood fiber and plastic, though the ratio, the plastic type, and how the board is finished vary a lot between manufacturers. Two distinctions matter most for a deck near the water in Marietta.
Capped vs. Uncapped
Capped composite boards have a plastic shell wrapped around a wood-plastic composite core, which protects that core from moisture absorption, staining, and UV fade. Uncapped composite is the older style of the product: the wood-plastic blend is exposed on all sides, so it absorbs moisture more readily and is more prone to mold growth and surface wear over time. In a salt-air, high-moisture environment like Marietta, that difference shows up faster than it would further inland, which is why we default to capped composite on jobs out here.
Cellular PVC as an Alternative
Some manufacturers also offer fully cellular PVC decking, which contains no wood fiber at all. PVC resists moisture absorption completely, even at cut edges and fastener holes, but it typically costs more than composite and can flex more under heavy point loads. For a deck that sits especially close to the bay or gets heavy shade and standing moisture, some homeowners decide the extra cost is worth it. We'll walk through both options honestly rather than pushing whichever carries a better margin.
What a Correct Composite Deck Build Involves Here
The decking boards get most of the attention, but in Marietta's climate, the framing, fasteners, and drainage details underneath are what actually decide how long the deck lasts. A build done right for this location includes:
- Framing material suited to sustained moisture exposure: pressure-treated lumber rated for the application and sized correctly for the span and load
- Stainless steel or coastal-grade corrosion-resistant fasteners throughout, not standard hardware that starts corroding in salt air within a few seasons
- Hidden fastener systems on the deck surface where the product allows, reducing exposed metal and leaving a cleaner walking surface
- Correct board gapping for drainage and material movement, so wind-driven rain and standing moisture can actually drain and dry between boards
- Proper ledger board flashing where the deck ties into the house, since that connection point is one of the most common places moisture gets in on a poorly built deck
- Joist spacing matched to the specific composite product's span rating rather than a generic wood-framing layout
- Railing and post attachment sized for the wind exposure the site actually sees, especially on decks closer to the bay or built up off grade
- Ventilation and grading underneath the deck so moisture doesn't sit against the framing between storms
Skip any one of those steps and the deck usually still looks fine on day one. The problems show up a few winters later, as a soft joist, a loosening railing post, or fastener corrosion staining the boards around it.
Design Considerations for Marietta Properties
Beyond material and structure, a composite deck near the water in Marietta has a few site-specific questions worth working through before anything gets built. Wind exposure affects how open a railing design can be versus how much wind-break value a partial screen or glass panel adds. Sun and shade patterns affect which decking colors will hold up best against fading and moss, since a shaded, bay-facing deck needs different moss-resistance priorities than one that gets sun most of the day. Grade and drainage around the house affect substructure design and whether extra attention is needed to keep water from sitting underneath the deck between storms. None of this is one-size-fits-all, which is part of why a deck built for a specific Marietta lot performs differently than a stock design dropped onto any site in the county.
How Our Process Works
We start with a site visit to look at what's actually there: existing structure condition if it's a replacement, drainage and grade around the deck area, sun and wind exposure through the day, and how close the site sits to the bay. From there we talk through composite product options that fit the budget and how the space will actually get used, whether that's a quiet spot off the kitchen or something built for entertaining.
Permitting in Ferndale and the rest of Whatcom County generally follows standard setback, structural, and elevation requirements, and we handle that as part of the job rather than leaving it for the homeowner to sort out. Once permitted, the build follows the sequence above: substructure and framing first, sized and fastened for the site's actual exposure, then the composite decking surface, railing, and any stairs or trim work. We finish with a walkthrough covering what the specific product you chose actually needs going forward, which for most modern composite is minimal, but not nothing.
Composite Decking Compared to the Alternatives
| Material | Handling Salt Air & Moisture | Moss Resistance | Upkeep |
|---|---|---|---|
| Cellular PVC | Excellent, no wood fiber to absorb moisture | Strong, smooth non-porous surface | Occasional washing |
| Capped composite | Strong, cap layer resists moisture and staining | Good on most product lines | Occasional washing |
| Uncapped composite | Moderate, some moisture absorption at exposed fiber | Fair, more prone to buildup over time | Periodic cleaning |
| Cedar | Moderate, natural resistance but needs sealing | Fair when sealed and maintained | Regular oiling or sealing |
| Pressure-treated wood | Weak against sustained salt exposure over time | Poor without regular treatment | Regular sealing or staining |
Exact costs and lifespans depend on the specific product line and the site's actual exposure, which is why we walk the property in person before recommending a material rather than quoting off a generic price sheet.
What Composite Decking Still Needs From You
Composite decking is low-maintenance compared to wood, not maintenance-free. A short list worth keeping in mind for a deck near Lummi Bay:
- Rinse or wash the deck surface periodically to clear salt residue, pollen, and organic buildup before it works into the surface or cap layer
- Keep gaps between boards clear of leaves and debris so water and airflow can move through the way the design intends
- Check railing posts and hardware once a year for early corrosion or loosening, especially heading into the wet season
- Trim back overhanging branches or plants that hold moisture against the deck or block sun and airflow across the surface
- Address any soft framing or standing water underneath right away: that's a structural issue, not a cosmetic one, and it doesn't improve with time
Why It Matters That We Already Work Marietta
A crew that mostly builds decks further inland can still install composite decking competently, but a Marietta job has variables that don't come up as often elsewhere in Whatcom County: corrosion-grade fastener requirements from sustained bay-side salt exposure, wind loads tied to open exposure near the water, and moss pressure that runs longer here than it does in more sheltered parts of the county. Working this area regularly means we're not guessing at those requirements on your project. We've seen which composite lines actually hold up against this specific combination of salt air, driving rain, and moss, and which fastener grades and framing details are worth the extra time rather than an upsell.
That familiarity also shows up in the smaller judgment calls: how to orient a deck for the wind a particular Marietta lot actually sees, or being straightforward about what a deck here realistically needs to last versus what's just an extra line item.
Get a Straight Answer About Your Deck
Whether you're replacing a tired deck, building new, or want an honest read on what composite decking would take on your Marietta property, we're happy to walk the site with you and lay out the options plainly. Reach out below for a free, no-pressure estimate.