Sunrooms & Patio Enclosures

Short answer: in the Denver metro, a *covered patio* is a roof only, a *three-season enclosure* is glazed but not conditioned, and a *four-season enclosure* is a conditioned addition. Choose on how you intend to use the room in January, because that answer sets the foundation, the envelope, the mechanical plan and the permit path — and retrofitting upward later is rarely economical.

• —Use it spring to fall, unheated. A covered patio or a screened enclosure is usually the honest answer, and it is the lightest permit path.
• —Use it most of the year, with a space heater on cold mornings. A three-season room with an appropriate glazing package.
• —Use it exactly like the rest of the house. A four-season conditioned addition, with energy-code compliance and either an HVAC extension or a dedicated mini-split.

Property and design coordination comes before drawings: lot setbacks, easements, any HOA architectural submittal, how the new roof meets the existing framing and snow-shed path, and where roof drainage discharges relative to walkways and the foundation. Envelope and mechanical performance is engineered per room rather than promised — glazing is specified against orientation, and conditioning capacity is confirmed with a load calculation rather than assumed from the existing furnace. Permit requirements are set by the jurisdiction that holds the parcel and are confirmed with that department; there is no single Denver-metro rule.

For a real example of covered-patio-scale exterior work, see the covered patio and window replacement we completed in Aurora. Where the room becomes conditioned living area, the planning is closer to our home additions service. To talk through which of the three a specific patio should become, request a consultation.

Four different projects get asked about as a *sunroom*, and they diverge at the foundation. Deciding which one you actually want is the single decision that sets the permit path, the structure and the budget — everything else follows from it.

• —Patio cover. A roof only, open on the sides. No glazing, no envelope, no conditioning. It shades a patio and keeps snow off, and it usually permits as an accessory structure. The engineering question is snow load and how the roof ties into the house.
• —Screened enclosure. A patio cover with screen walls. Keeps insects and blown debris out, but it is outdoor space in every other respect. Often buildable over an adequate existing slab.
• —Three-season room. Glazed and weather-tight, sometimes lightly insulated, comfortable across roughly spring through fall on the Front Range. Not conditioned to the standard of the house, and not counted as living area.
• —Four-season conditioned room. Legally and structurally an addition: foundation, insulated envelope, energy-code compliance, mechanical extension or a dedicated mini-split. It is the only version that becomes finished living area, and it is priced accordingly — the same planning logic as any other addition, covered in our Denver metro home addition cost guide.

Retrofitting upward — screened to three-season, three-season to four-season — is almost always more expensive than building the higher classification the first time, because the foundation and framing were sized for a different load and envelope.

We do not publish fixed sunroom prices, because the classification decision above changes the project by an order of magnitude and the site changes it again. What we can set out is what the estimate is actually made of, in rough order of impact:

• —Classification. Conditioned space carries foundation, insulation, energy-code and mechanical costs that a screened enclosure simply does not have.
• —Foundation. Whether an existing slab can be reused, or whether a turned-down slab, frost-protected shallow foundation or full stem wall is required for the soil and the room type.
• —Glazing area and specification. Square footage of glass, the low-E package chosen for the orientation, and hail rating along the I-25 corridor.
• —Roof tie-in complexity. A simple single-story eave is straightforward; tying beneath a second-story overhang, into a valley, or where the existing roof sheds snow onto the new one is not.
• —Mechanical strategy. Extending existing HVAC when a load calculation shows capacity, versus adding a dedicated mini-split and its electrical circuit.
• —Site access. Whether concrete, framing and glass can reach the back of the house, or whether everything is carried through a gate.
• —Engineering and permit path. Stamped structural drawings and energy-code documentation for conditioned rooms; lighter requirements for accessory structures.

The classification also decides which review you sit through. In Littleton, where we are registered and work most often, a conditioned room is reviewed as an addition against setbacks and lot coverage on lots that are frequently tighter than they look. In Denver, rear-yard coverage limits and the zone district commonly decide how much enclosed space is possible at all before anyone discusses glazing. In Centennial and the surrounding south-metro jurisdictions, larger lots more often leave room for a full four-season addition, and the constraint shifts to snow shed off the existing roof and to HOA architectural review.

In every case we confirm the permit path with the department before design is committed, so the drawings that go in for review are already built to the standard that jurisdiction expects.