How Gas Fireplace Installation Works: From First Conversation to First Flame

Most homeowners we talk to have the same picture in their head: they call us, we show up, we install a fireplace. The reality is a five-phase process — and the phases before the install day are usually where the project succeeds or fails. Here's what the Prime process looks like from first call to first flame, and why each phase matters.

Phase 1: The design conversation

We don't start with a tape measure. We start with a conversation about the room. Where is the fireplace going? Is this a living room focal point, a bedroom accent piece, or a great-room primary heat source? Is the surround going to be painted shaker to match existing millwork, or a full-height stone slab from floor to ceiling?

These aren't aesthetic side questions. They determine which unit goes in, what venting path is possible, how much gas line work is needed, and whether framing is in scope. A gas insert into an existing masonry firebox has a completely different scope from a new-build direct-vent linear in a room with no existing chimney. The design conversation is what tells us which path we're on.

We schedule an in-room walkthrough — not a phone quote, not an estimate based on square footage. We need to see the room to give you a real number.

Phase 2: Site assessment

The walkthrough is also where we assess the physical install path. On a typical Bellevue project, we're answering:

• Venting path. Does an existing masonry chimney make a co-linear liner the right move, or is a new direct-vent termination through the wall or up through a new chase the correct path? Where does that termination land relative to windows, rooflines, and setback requirements?
• Gas line. Where is the nearest gas supply? What's the existing BTU capacity? Is a new line required, and if so, how far does it need to run and through what walls or floors?
• Electrical. Does the unit require a dedicated outlet (most do, for the blower and ignition system)? Is there an existing outlet at the right location, or does an electrician need to rough in?
• Framing scope. Is an existing masonry firebox structurally sound and the right proportions for the insert we've selected? Or are we opening a wall, framing a new firebox, and building a chase?

The site assessment is also where we catch the surprises — a gas line buried in a slab, a load-bearing wall in the direct-vent path, a two-story chase that needs more framing scope than expected. Better to find these in phase 2 than on install day.

Phase 3: Permits

Every gas fireplace installation on the Eastside requires permits. The City of Bellevue requires a mechanical permit for the appliance and a gas piping permit for the gas line connection. Kirkland, Redmond, Mercer Island, Issaquah, and Sammamish each have their own permitting requirements, though the categories are similar. Washington State Labor & Industries adds a state-level layer on top of the city permits.

Prime pulls every permit. We don't subcontract the permit applications or leave them to the homeowner. Our project coordinator handles the applications, tracks the approval timelines, and schedules the inspections. The permit and inspection timeline is what adds calendar time to the project — typically two to four weeks between application and first inspection window. That window is the reason we say first-flame timeline runs three to six weeks from first call, not two days.

Phase 4: Install day(s)

A gas insert into existing masonry is usually one on-site day. The firebox gets cleaned out, the insert drops in, the co-linear liner runs up the chimney, the gas connection is made, the unit is tested, and the surround goes on. If the surround involves new stone or custom millwork, that finish work may be a separate day.

A new-build direct-vent or linear fireplace with framing, new venting, and a custom surround is typically two to five on-site days depending on scope. The sequence is: framing first, then rough-in inspections, then unit set, then gas connection, then finish work.

Our crews work clean — floor protection, daily cleanup, no tools left overnight unless the homeowner has cleared it. Most installs involve some drywall opening (even on inserts, if the gas line needs a new run) — we close those openings and leave them in paintable condition.

Phase 5: Inspection and walkthrough

After the install, we schedule the city inspections — gas piping first (before any wall is closed), then final. The inspector verifies the gas connection, the appliance installation, and the venting termination. On new-build projects, there may be a framing inspection in the middle of the sequence.

Once inspections are passed and permits are closed, we do a homeowner walkthrough. We cover how to operate the unit (remote programming, thermostat settings, manual ignition backup), what the maintenance schedule looks like, what the manufacturer warranty covers, and what our labor warranty covers. You leave the walkthrough knowing how to use every function of the fireplace and who to call if anything ever needs attention.

Insert vs. new-build: two different timelines

Prime runs every install as a designer-led project — design conversation first, install second, walkthrough third. Schedule your in-room walkthrough and we'll walk the five phases as they apply to your specific room.