Garage Construction Project

Mechanical Room

4 min read

Location & Layout

  • Preferred location:
  • Clearances: maintain manufacturer service clearances around all equipment.
  • Floor: confirm PEX routing under walls; avoid PEX under anchor points.
  • 2025-10-13 contract includes enclosed stair with small mechanical closet; coordinate final wall dimensions before framing to ensure equipment fits.

Critical Dependencies: Boiler Operation Timeline

Boiler installation and operation require sequential completion of multiple systems with significant lead times. Do not expect boiler operation until late December at earliest; early January is more realistic.

Lead Time Items (Must Start Immediately)

  1. Electrical Service Installation ⏱️ 2-4 weeks

    • Licensed electrician pulls 200A wire through existing underground conduit
    • 200A panel installation in mechanical room
    • 100A feed from house panel
    • Meter installation and energization
    • Permit and inspection approval
    • Action: Contact licensed electrician immediately for quote and scheduling

  2. Natural Gas Service Installation ⏱️ 2-4 weeks

    • Licensed gas fitter pulls PE pipe through existing underground conduit
    • Underground burial and pressure testing
    • Gas line termination and inspection
    • Action: Contact licensed gas fitter immediately for quote and scheduling

  3. Boiler Venting Route ⏱️ Must be confirmed before framing (Stage 3)

    • Boiler manufacturer specifications determine vent route
    • Flue vent penetration through wall/roof
    • Proper termination clearances per code
    • Must be planned during Stage 3 framing
    • Action: Review boiler model vent requirements; confirm route before wall framing

Sequential Dependencies

MECHANICAL ROOM FRAME (Stage 3)
        ↓
  Electrical Service Install (licensed electrician)
  AND
  Gas Service Install (licensed gas fitter)
        ↓
  Boiler Installation (professional)
        ↓
  System Commissioning
        ↓
  RADIANT HEAT OPERATIONAL

Critical Path: All three installations (framing, electrical, gas) must complete before boiler can operate. Any delay cascades.

Notes on Winter Timeline

  • High-demand season (Dec 1 - Jan 31): Electrical and gas contractors typically fully booked
  • Expect 2-4 week scheduling delays during winter months
  • Best-case scenario: Boiler operational mid-December
  • Realistic scenario: Late December to mid-January
  • Spring scheduling (Mar-Apr): Faster contractor availability if winter operation not critical

Insulation Sequencing Impact

Important: Operating boiler in uninsulated garage is inefficient and wastes fuel. Before or concurrent with boiler startup, complete:

  • Mechanical room: Full insulation + drywall (should be done before boiler installation anyway)
  • Perimeter wall air-sealing minimum (seal around penetrations, rim joists)
  • This dramatically improves boiler efficiency and working comfort

See: Winter Construction Strategy for detailed timing analysis and alternative strategies.

Equipment & Services

  • Radiant heat boiler (NG): flue/combustion air, condensate drain, gas, electric.
  • Radiant manifolds: supply/return placement, isolation valves, purge points.
  • Electrical service/panel: ampacity, working clearances, feeder/conduit path.
  • Mini-split provisions: line-set sleeves, condensate drain, outdoor unit disconnect.
  • Domestic water/sewer rough-ins (future bath/laundry upstairs).
  • Low-voltage: network cabinet, conduit to house.

Penetrations & Rough-Ins

  • Gas: sleeve and shutoff location.
  • Flue/vent: route and termination per code (sidewall/roof; clearances).
  • Condensate: dedicated drain to approved location with trap/neutralizer if required.
  • Condensate for mini-split (if indoor head nearby): route with slope.

Electrical

  • Dedicated circuits: boiler, pumps, mini-split outdoor unit, server rack, lighting.
  • Receptacles: utility outlets at work height; GFCI where required.

Actions

  • Freeze mechanical room location and wall layout. — stage:: 2
  • Mark PEX-free zones for wall anchors and penetrations. — stage:: 2
  • Place sleeves for gas, condensate, line-sets, and low-voltage before pour/framing as needed. — stage:: 2
  • Confirm boiler vent route and termination location. — stage:: 4
  • Coordinate panel location and service entrance route. — stage:: 3
  • Update one-line electrical and hydronic schematics. — stage:: 2
  • Confirm PEX tube depth near mechanical room walls; select appropriate anchor length for treated 2×4 sill to slab — stage:: 2

After Build / Commissioning

  • Set electrical service/meter and energize panel; label circuits — stage:: 6
  • Install boiler and manifolds; commission radiant heat (purge, venting, leak check) — order:: Boiler and Radiant Order — stage:: 6

Procurement

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