3555 4th St, Boulder, CO 80304

• 4 beds |
• 5 baths |
• 4,218 sqft

Property Description

Set into the foothills at the base of Mount Sanitas, 3555 4th Street is a study in organic modernism, where limestone, steel, & expanses of glass blur the line between home & landscape. Designed by Fanas Architecture, the home is a work of architectural integrity, realized at the highest level of craft. A smooth limestone spine wall threads through the home, with rough-hewn limestone as a counterpoint. In the great room, exposed steel I-beams frame 24-foot retractable walls of glass, opening to north & south-facing patios. European white oak with radiant heat runs underfoot, beneath a floating wood-plank ceiling washed in cove lighting. The chef's kitchen by EKD features custom walnut cabinetry, a hand-laid mosaic backsplash, Dornbracht fixtures, & Gaggenau appliances. Built-ins flow through the butler's pantry, mudroom, & laundry. A main-floor flex suite serves as primary, office, or guest, complete with walk-out patio, walnut walk-in closet, & Japanese-inspired bath in Vola fixtures. The primary suite opens to the second-story deck through wall-to-wall sliding glass. Behold a coved wood plank ceiling, pin lights, and sculptural pendants. The primary bath is a masterful blend, anchored by a freestanding MTI resin tub, with a steam shower, bespoke cabinetry, alabaster sconces, & a custom walk-in closet. A loft with a wet bar adjoins two ensuite bedrooms. Over 3,200 square feet of finished exterior living space spans three levels, redefining outdoor living in Boulder. The south terrace pairs an overhang & electronic louvres with a fire pit & water features. Steel stairs rise to the upper deck, unveiling a hot tub, cantilevered overhang, and Sanitas to the west. Above, a rooftop deck opens to panoramic views. Lutron lighting on Control4, radiant heat across nine zones, full solar array, & two EV-charging rough-ins. Steps from the Goat trail and tucked into one of Boulder's most iconic neighborhoods, 3555 4th Street is a triumph of detail, intention, & place.

Listing Status:

Active

Data Last Updated:

May 20, 2026 at 8:23PM

Listing Office:

Coldwell Banker Realty 02 : 7204700910

Listing Agent:

Lucy Conklin : 7204700910

MLS ID:

1058738

Interior

• General: Eat-in KitchenSeparate Dining RoomOpen FloorplanPantryWalk-In Closet(s)Wet BarWasher/Dryer HookupKitchen IslandHigh Ceilings
• Rooms: Loft
• Appliances: DisposalFire Alarm
• Basement: None
• Flooring: Wood
• A/C: Central Air
• Heating: Forced AirZonedRadiantHumidity Control
• Fireplace: Multi-SidedGreat Room
• Disability Feature: Level LotWidth of Hallways 42" or moreInterior Door Openings 32" plusExterior Door Openings 36" plusMain Floor BathMain Level BedroomStall ShowerMain Level Laundry
• Eco/Green Feature: WindowsHigh Efficiency FurnaceEnergy RatedPhotovoltaic Owned

Exterior

• General: Sprinkler SystemBalconyHeated GarageOversized Garage
• Style: Contemporary
• Other Structures: DeckPatio
• Parking: Attached

Construction

• Roofing: Rubber
• Windows: Window Coverings
• General: StoneCompositionTwo

Location

• Road/Access: City Street
• Originating MLS: ires
• School District: Boulder Valley Dist RE2
• County: Boulder

Lot

• Zoning: SFRR0033198
• View: Hills
• Fencing: FencedWoodOther

Utilities

• Utilities: Natural Gas AvailableElectricity AvailableCable AvailableSatellite AvailHigh Speed AvailXcel Energy
• Water: City
• Sewer: Public Sewer

Financial

• Source: ires
• Exclusions: Staging items