Green Lake Re-Side — James Hardie Cedarmill Over R-6 Exterior Insulation

Green Lake is full of tall, character-rich houses on small lots, and this one is a perfect example: three stories at the back gable, original leaded-glass windows, and a neighboring house just a few feet away. The owners wanted the old siding gone and a wall that actually performs in Seattle’s climate. So we rebuilt the assembly from the sheathing out — HydroGap drainable housewrap, new Marvin windows liquid-flashed into the wrap, R-6 continuous exterior insulation, a vented plywood rainscreen, and 7-in James Hardie Cedarmill lap — and finished it with a custom two-story window tower in Hardie panel and trim.

Tear-off on a lot with almost no room to work

The honest version: this was a hard house to stage. The work faces sat over a narrow side yard, the back gable is three stories up, and one elevation could only be reached by bridging ladder-jack staging over the porch roofline. We planned the access before we planned anything else — protecting the roof below, the landscaping, and the neighbor’s side of the property line — because a crew that can stand comfortably everywhere it needs to is what makes the rest of the job come out right.

With the old cladding off, we took the walls back to solid sheathing and papered off the openings so the house stayed dry while the new assembly went on.

New Marvin windows — liquid-flashed into the HydroGap WRB

Every re-side we do starts with water management, and on this house that meant the openings. We wrapped the walls in Benjamin Obdyke HydroGap — a drainable housewrap with built-in spacers that let water run down and out instead of sitting behind the cladding — and with the walls open we installed new Marvin windows, waterproofing each one with HydroFlash liquid-applied flashing. Liquid flash is gunned and tooled into the sill, jambs, and head of each opening, curing into one continuous membrane with no tape laps or fishmouths to fail, and it bonds directly to the HydroGap so the windows and the wall drain as a single system. A re-side is the one moment a wall is fully open, and setting the windows at the same time means the flashing integration is built right rather than retrofitted through existing siding.

R-6 continuous exterior insulation — Hunter Panels polyiso

Over the WRB went R-6 rigid polyiso from Hunter Panels, run continuously across the wall with taped seams. Insulating outside the studs is the upgrade older Seattle houses actually need: framing is a thermal highway through the wall, and a continuous layer of foam shuts it down. It also keeps the sheathing warmer, which pushes the dew point out of the wall cavity — less condensation risk through the long wet season, lower heating bills the rest of the year.

The rainscreen — 1/2-in x 2-in pressure-treated plywood furring

You can’t nail siding to foam, and in this climate you never want cladding trapped tight against the wall. So over the insulation we ran a rainscreen of 1/2-in x 2-in pressure-treated plywood strips, fastened through the foam into the framing. The furring does two jobs at once: it’s the solid fastening base for the Hardie, and it holds the siding off the wall so there’s a vented cavity behind every course — anything that ever gets past the cladding drains down and out, and the back of the boards can dry. We use plywood rather than sawn battens over foam because it stays flat and holds fasteners well, and pressure-treated because a rainscreen cavity is a damp place by design. It’s the same building science we walk through on our rainscreen systems page.

7-in James Hardie Cedarmill lap + HardieTrim

The cladding is HardiePlank in the Cedarmill texture, hung in 7-in courses that suit the scale of these tall walls — fiber cement with a brushed cedar grain that reads as wood from the street but doesn’t rot, feed woodpeckers, or need repainting every five years. Corners, bands, and openings are finished in HardieTrim, cut edges primed as we went, and every penetration — meter, outlets, hose bibs, vents — got its own trimmed mounting block instead of caulk-and-hope. We also kept the house’s original leaded-glass windows and trimmed them out against the new lap, so the character that makes the house belong in Green Lake survived the upgrade.

The custom build-out — a two-story window tower in Hardie panel and trim

The centerpiece of the back of the house is a two-story window bay: stacked banks of divided-light Marvin windows over a folding glass door to the patio. We built the tower out in smooth James Hardie panels with HardieTrim battens laid in a paneled grid, so the whole feature reads like a piece of cabinetry rather than siding. Painted bright white against the deep blue lap, it’s the detail everyone asks about.

The takeaway

Under the paint, this is a wall built for the Pacific Northwest: a drainable wrap, liquid-flashed openings, continuous R-6 insulation, a vented rainscreen, and fiber cement that will hold its lines for decades. It looks like it has always been part of Green Lake — it just performs like it was built this year.

If your house needs that same mix of respect and upgrade — tight lot, tall walls, character worth keeping — this is exactly the work we do as a Seattle siding contractor, and the assessment is free.