Colorado 12x18

The Large Enclosed Gazebo for Oversized Hot Tubs and Compact Swim Spas

The Colorado 12×18 sits in a unique position in the Colorado collection — it is the size that bridges the gap between a dedicated hot tub enclosure and a full swim spa shelter. With interior dimensions of approximately 132 5/8″ x 203 7/8″, this large, enclosed gazebo provides enough floor space to house an oversized 8-person hot tub with a full lounge area, or a compact swim spa (up to approximately 14 feet in length) with clearance for entry, maintenance access, and a small seating area at one end.

Homeowners who find the 12×16 a bit tight for their intended setup but do not need the full 20-foot length of the 12×20 will find the Colorado 12×18 to be the ideal middle ground. The extra two feet of interior length compared to the 12×16 open up meaningful options: enough room for a sectional sofa alongside your hot tub, space for a small exercise area next to your swim spa, or the ability to add a TV, wet bar, or refreshment station without the room feeling cramped.

Ultrawood Construction: Premium Looks, Zero Maintenance

The Colorado 12×18 is built from Ultrawood composite — the same heavy-duty material used across the entire Colorado line. Ultrawood mimics the grain, texture, and color depth of natural wood while eliminating every maintenance requirement that comes with real timber construction. It does not rot, crack, fade, or attract insects. It never needs staining, sealing, painting, or sanding. For a structure this size, the maintenance savings alone add up to hundreds of dollars and dozens of hours over the lifetime of the gazebo.

The coastal gray wall panels paired with driftwood gray accents on the windows and doors create a modern, refined appearance that integrates naturally with virtually any home style or landscaping design. Several Colorado 12×18 owners have told us that the enclosure looks like it was built by a local contractor as a permanent room addition rather than delivered as a prefab structure — a testament to the quality of the Ultrawood finish and the attention to detail in the panel design.

Heavy-Duty Duraflex Roof for Northern Climates

The Duraflex PC roof on the Colorado 12×18 is rated to support up to 35 lbs. per square foot of snow load or up to 40 lbs. per square foot with the roof bracket upgrade kit. At this larger roof span, engineering becomes increasingly important — a wider and longer roof catches significantly more snow and rain than a smaller model. The Duraflex hardtop polycarbonate system is specifically designed to handle that load safely and consistently, making the Colorado 12×18 a smart choice for hot tub and swim spa owners in snow-heavy states like Minnesota, Michigan, Colorado, and the Pacific Northwest.

A centered skylight in the roof peak allows natural daylight to fill the interior, which is particularly important in a structure this size. Without adequate light, a large, enclosed space can feel dark and enclosed. The skylight solves that, creating a bright and welcoming atmosphere during the day and a view of the night sky for evening hot tub sessions. Six aluminum-framed sliding glass windows provide additional light, airflow, and temperature control. Every window locks securely for year-round all-weather protection.

Assembly, Access, and Practical Planning

The Colorado 12×18 ships as a pre-assembled panel kit. Wall sections, roof panels, windows, doors, and hardware all arrive ready for on-site assembly. At this size, plan for two to three people and a full day to complete the build comfortably. A power drill, tape measure, level, step ladder, and a pair of wood clamps are the essential tools. Westview’s detailed illustrated instruction manual and unlimited toll-free phone support (1- 800-895-1972) are included with every order.

Two lockable aluminum French doors can be placed on any side of the structure. This customizable door placement is especially valuable with a larger gazebo because it allows you to align the entrance with your existing walkway, deck, or patio access point. The lockable doors and windows provide full security and hot tub privacy when the space is not in use.

For homeowners in jurisdictions that require building permits for structures of this size, Westview offers an engineering stamp document that provides the resources you need for permit applications and HOA approvals. A properly prepared concrete pad or reinforced deck is recommended as the foundation if using the Colorado 12×18 for hot tub or swim spa use.

Upgrades and Financing

Customize your Colorado 12×18 with optional screen kits, tempered glass window upgrades, and reinforced roof bracket supports. Screen kits are perfect for three-season use in areas with heavy insect activity. Tempered glass improves thermal insulation, safety, and soundproofing. Roof brackets boost the structural rating for homeowners in extreme wind or snow regions. All upgrades can be bundled at a package discount. Affirm financing is available at checkout. Call 1-800-895-1972 to discuss sizing, upgrades, or delivery.