Utilities & Conduits

Conduits Installed - Foundation Poured (2025-10-30)

All utility conduits successfully installed through foundation:

• ✓ 5x conduits installed (1x 3” sewer, 4x 2” utilities)
• ✓ Concrete foundation pour completed
• ✓ Conduits integrated with radiant heating PEX and fiberglass rebar systems
• ✓ All embedded systems operational and protected

Next Steps:

• Concrete curing period (7-28 days)
• Future utility installation through conduits (gas, water, electrical, low-voltage)
• Coordination with licensed contractors for trenching and connections

House-to-Garage Utility Routing Strategy

Two Separate Underground Trenches Required

See aerial property view: DJI_0005_Utility_Routes for visual reference of utility paths.

Overview

Utilities will run from the existing house to the garage via two separate underground trenches, both terminating at the garage foundation where they enter through conduits into the mechanical room.

Trench 1: Electrical Service (RED arrow path)

Route: House SW corner → Garage foundation (separate trench)

Why separate: Multiple electricians insisted that electrical service should run in its own dedicated trench, separate from other utilities. This is preferred practice for several reasons:

• Different burial depth requirements
• Separation from gas and water lines
• Independent trenching timeline/contractor
• Easier troubleshooting and future maintenance

House Connection Point:

• Power enters house via underground service line at SW corner (exterior)
• Runs up to Consumers Energy meter on exterior wall
• Enters basement and terminates at existing 200A breaker panel (west wall, south corner)
• New garage feed will tap from this main panel

Electrical Service Specifications:

Future-Proofing Strategy: 200A Wire, 100A Connection

Wire Capacity: 200 amp rated wire will be buried (e.g., 2/0 AWG copper or 4/0 AWG aluminum) Initial Connection: Connected to 100 amp breaker at house main panel Garage Panel: 200 amp breaker panel installed in garage

Rationale:

• Electricians consensus: 100A service is plenty for garage (lighting, outlets, lift, compressor, mini-split, etc.)
• However, running 200A capacity wire NOW is smart future-proofing
• Cost difference for wire is minimal compared to digging new trench later
• If house is ever upgraded to 400A service, garage can be upgraded to full 200A by simply changing breaker at house
• 200A panel in garage allows for future expansion without panel replacement

Burial Specifications:

• Depth: Per NEC requirements (typically 18”-24” depending on wire type/protection)
• Wire type: THWN-2 or XHHW-2 individual conductors in conduit, or direct-burial rated cable
• Conduit: 2” PVC through foundation (already installed), may require larger conduit for burial section depending on wire size
• Ground: Proper grounding and bonding per NEC requirements
• Installation: Licensed electrician required, permit and inspection required

Trench 2: All Other Utilities (BLUE arrow path)

Route: House connection point → Garage foundation (separate path from electrical)

Why bundled: All non-electrical utilities can share a common trench:

• Cost efficiency (single trench excavation)
• Easier coordination with plumber/HVAC contractor
• Similar burial depth requirements
• Reduced property disruption

Utilities in this trench:

1. Sewer (3” pipe)

   • 3” PVC pipe at appropriate slope
   • Connects to main house sewer stack
   • Through foundation: 3” conduit stub (already installed)

2. Natural Gas (PE pipe, minimum 1”)

   • Flexible PE polyethylene pipe (PE 2708 or PE 4710)
   • Recommended: 1” IPS for garage heater + future appliances
   • Direct burial rated, yellow tracer wire required
   • Through foundation: 2” PVC protective sleeve (already installed)
   • See Natural Gas Line (PE Polyethylene Pipe) section for detailed specs

3. Water (PEX, maximum 3/4”)

   • Direct burial ASTM F2023 standard PEX
   • 3/4” maximum (house has 3/4” service from city)
   • Through foundation: 2” PVC protective sleeve (already installed)
   • See Water Line (PEX) section for detailed specs

4. Low Voltage (2” PVC conduit with pull cables)

   • 2” PVC conduit for future-proofing (fiber, network, coax, phone, etc.)
   • Pull cables installed for easier future wire installation
   • Through foundation: 2” PVC conduit (already installed)
   • Primary use: 10GbE fiber connection to garage network switch
   • See Low Voltage / Data section for detailed specs

House Connection Point:

• Exact location TBD (different from electrical service entry point)
• Will connect to respective house systems: sewer stack, gas line, water supply, network panel

Code-Compliant Burial Depths & Separation Requirements

Climate Zone & Frost Depth

Location: Clare, Michigan (Central Michigan, Climate Zone 6a) Frost Depth: 42 inches minimum (Michigan Residential Code Table R301.2) Verification: Contact Clare County Community Development (989-539-2761) to confirm local requirements

This section provides code-compliant specifications for Trench 2 utility installation to ensure proper depth, separation, and bedding for freeze protection and code compliance.

Minimum Burial Depths (Per Code)

Each utility in Trench 2 has specific minimum burial depth requirements based on Michigan codes and federal standards:

1. Sewer (3” PVC) - DEEPEST UTILITY

• Minimum Depth: 42 inches to top of pipe (Michigan Plumbing Code)
• Trench Depth: 48 inches (42” + 6” sand bedding below pipe)
• Why Deepest: Must run below all other utilities for sanitary protection
• Code Reference: Michigan Plumbing Code 2015/2018, Chapter 30 (Sanitary Drainage)

2. Water (3/4” PEX)

• Minimum Depth: 42 inches below frost line = 42” to top of pipe
• Code Reference: Michigan Plumbing Code Section 305.4 (Freezing protection)
• Installation: Must be below frost line (42”) and at least 12” below grade

3. Natural Gas (1” PE Pipe)

• Federal Minimum: 24 inches (49 CFR 192.327 - Federal Pipeline Safety Standards)
• Michigan Best Practice: 42 inches (below frost line for freeze protection)
• Tracer Wire Required: Yellow 12-14 AWG copper, continuous, accessible at both ends
• Code Reference: 49 CFR Part 192, Michigan Gas Safety Standards (MPSC R 460.20101-20606)

4. Low Voltage (2” PVC Conduit)

• Minimum Depth: 18 inches for residential PVC conduit (NEC Table 300.5)
• Recommended: 24-42 inches for additional protection and frost avoidance
• Code Reference: National Electrical Code (NEC) Table 300.5

Separation Requirements (Horizontal & Vertical)

Utilities must be properly separated to prevent contamination, allow maintenance access, and meet code requirements:

Sewer to Water Separation (Michigan Plumbing Code - Critical):

• Option 1: 5 feet minimum horizontal separation (preferred)
• Option 2: 12 inches vertical separation (water ABOVE sewer) if within 5 feet horizontally
• Rationale: Prevents potable water contamination from sewer leaks
• Code Reference: Michigan Plumbing Code Chapter 26, Section P2603.2

Natural Gas Clearance (Federal Gas Pipeline Standards):

• Minimum: 12 inches clearance from any other underground structure
• Best Practice: 12-18 inches from all utilities (water, sewer, low-voltage)
• Rationale: Allows proper maintenance and protects from damage
• Code Reference: 49 CFR 192.325 (Underground clearance)

General Best Practices:

• Water to Low-Voltage: 12-18 inches horizontal separation
• Gas to Low-Voltage: 12 inches minimum horizontal separation
• All utilities staggered horizontally within trench when possible

Recommended Trench Profile (Vertical Stacking)

To meet all code requirements efficiently, the following vertical arrangement is recommended:

Grade Level (0")
    ↓
    |  18" ← Low-Voltage PVC conduit (minimum depth)
    |         Can be installed at 24-42" for better protection
    |
    |  42" ← Water PEX (frost line depth)
    |  42" ← Natural Gas PE pipe (recommended depth, 24" minimum)
    |         Water, Gas, and Low-Voltage can share same depth
    |         if horizontally separated by 12-18"
    |
    |  42" ← Sewer pipe TOP (must be deepest)
    |  48" ← Trench bottom (allows 6" sand bedding under sewer)

Horizontal Layout Within Trench:

• Position 1: Sewer (deepest, centered or to one side)
• Position 2: Water (12”+ from sewer, 12” above sewer if within 5 feet)
• Position 3: Gas (12”+ from water and sewer)
• Position 4: Low-Voltage (12”+ from gas, can be shallower)

Bedding & Backfill Specifications

Proper bedding and backfill protects utilities and ensures code compliance:

Sewer (3” PVC):

• Bedding: 6 inches of sand or fine gravel below pipe (Michigan Plumbing Code)
• Initial Backfill: 6 inches of pea gravel or sand above pipe crown
• Final Backfill: Loose earth free from rocks in 6-inch layers, compacted
• Cover: Minimum 12 inches of tamped earth above pipe crown before heavy backfill
• Rock Removal: If rock encountered, remove to 3” below pipe level, backfill with sand

Water (3/4” PEX):

• Bedding: 2-4 inches of sand below pipe (protects PEX from sharp objects)
• Backfill: Native soil acceptable if not rocky, sand preferred for PEX protection
• Insulation: Consider adding rigid foam insulation above pipe in first 10 feet from house for extra freeze protection

Natural Gas (1” PE Pipe):

• Bedding: Native soil acceptable if not rocky or frozen
• Backfill: Native soil in 6-inch layers, compacted
• Tracer Wire: Lay alongside pipe, maintain continuity, bring to surface at both ends
• Warning Tape: Optional yellow “CAUTION GAS LINE” detectable warning tape 12” above pipe

Low Voltage (2” PVC Conduit):

• Bedding: Native soil acceptable
• Backfill: Native soil in layers
• Warning Tape: Optional blue “CAUTION BURIED CABLE” tape 12” above conduit

Code References & Verification

Michigan Codes Applicable:

• Michigan Residential Code 2015 - Frost depth requirements (Table R301.2)
• Michigan Plumbing Code 2015/2018 - Water and sewer burial depths, separation requirements
• National Electrical Code (NEC) - Table 300.5 for electrical/low-voltage conduit depths

Federal Codes Applicable:

• 49 CFR Part 192 - Natural gas pipeline safety standards (burial depth, clearance)

Local Authority:

• Clare County Community Development
  • Address: 225 W Main St., Harrison, MI 48625
  • Phone: 989-539-2761
  • Jurisdiction: Handles all building, plumbing, mechanical permits for City of Clare
  • Action Required: Verify frost depth and any local amendments before excavation

Permit Requirements:

• Plumbing Permit: Required for sewer and water connections
• Gas Permit: Required for gas line installation (licensed gas fitter only)
• Electrical Permit: Required for low-voltage conduit if pulling electrical cables
• Inspections: Trench inspection required before backfill for all utilities

Installation Notes

Critical Installation Reminders

1. Sewer must be deepest - Cannot be above water or gas lines
2. Licensed contractors required - Plumber for water/sewer, gas fitter for gas line
3. Inspection before backfill - Do not cover trench until inspector approves
4. Tracer wire for gas - Required, must be continuous and accessible
5. Proper slope for sewer - Maintain 1/4” per foot slope toward house
6. Frost protection - All utilities except low-voltage must be at/below 42” frost line

Garage Termination Points

Both trenches terminate at the garage foundation perimeter where utilities transition through the foundation via conduits/sleeves into the mechanical room area.

Through-Foundation Conduits (already installed as of 2025-10-22):

• 1x 3” PVC for sewer
• 4x 2” PVC for gas, water, electrical, and low-voltage
• All conduits use long-radius 90° bends for easier wire/pipe pulling
• Vertical stubs through slab, horizontal extension past foundation
• See Conduit Specifications section below for installation details

Visual Reference: See DJI_0005_Utility_Routes for aerial view showing:

• RED arrow: Electrical service trench path
• BLUE arrow: Other utilities trench path
• Both paths converge at garage foundation

For detailed rationale and electrician recommendations, see: Utility Conduit Details

Conduit Specifications

Sewer Conduit

• Size: 1x 3” PVC conduit
• Purpose: Sewer line to house
• Location: Through mechanical room slab near in-floor heating PEX manifold
• Installation: Vertical stub through slab with 90° turn to extend past foundation, capped for future connection

Utility Conduits (4x 2” PVC)

Contractor (Terry) will install four 2” PVC conduits through the mechanical room slab for future utility connections:

1. Natural Gas Line

   • 2” PVC protective sleeve
   • Will contain CSST (yellow corrugated stainless steel tubing) or PE gas pipe
   • Requires sweeping 90° bend to pull flexible gas line through

2. Water Line

   • 2” PVC protective sleeve
   • Will contain underground-rated PEX tubing
   • Both water supply and potential return line from garage

3. Electrical Service

   • 2” PVC conduit
   • Will contain electrical conductors for garage subpanel
   • Standard NEC conduit requirements apply
   • Critical: Electrical wire very difficult to pull through standard 90° elbows

4. Low Voltage / Data

   • 2” PVC conduit
   • Future fiber optic, network cable, coax from house to garage
   • Will support 10GbE fiber connection to garage network switch
   • See homelab project for detailed network implementation

Cellular Connectivity Consideration

Metal roof will significantly attenuate cell phone signals in upstairs loft area (20-30 dB reduction typical). WiFi calling via garage AP provides partial solution, but cellular signal booster recommended for full functionality and redundancy. Booster requires 1” conduit from gable end to loft ceiling for coax cables during construction. See homelab project Cellular Connectivity.md for detailed analysis and implementation plan.

Critical Installation Requirements

Long-Radius 90-Degree Bends Required (CRITICAL)

All four 2” utility conduits MUST use long-radius (sweeping) 90-degree bends instead of standard elbows:

• Standard 90° elbows have short radius - very difficult to pull wire/pipe through
• Long-radius 90° bends have gentle curve - much easier for pulling utilities
• Minimal cost difference but enormous functional difference
• Without sweeping 90s, conduits may be unusable for their intended purpose
• This cannot be fixed after concrete is poured - absolute must-have

Pull Strings Not Required

Pull strings are NOT needed in these conduits:

• Conduits will be capped on both ends until future connection
• Strings would likely fall or tangle in vertical section over time
• With long-radius bends, easy to fish later using 125’ fish tape
• Can run fish tape from house through conduit to garage when ready to pull utilities

Installation Details

• PVC Type: Schedule 40 preferred (thicker walls, more durable than Schedule 35)
• Location: Mechanical room area where in-floor heating PEX tubes emerge from concrete
• Configuration: Vertical stubs through slab, then 90° turn (horizontal) to extend past foundation
• Extension: Conduits should extend 2-3 feet minimum past foundation edge for comfortable connections
• Protection: All conduits capped at exterior to prevent debris/water entry
• Depth: Below frost line per local code (typically 36”-48” in Michigan)
• Spacing: Adequate separation between conduits for future work

Future Utility Installation Specifications

This section details what will be pulled through each conduit when ready to connect utilities from house to garage.

Natural Gas Line (PE Polyethylene Pipe)

Recommended Solution: PE Gas Pipe

• Material: PE 2708 or PE 4710 polyethylene pipe (black or yellow)
• Purpose: Specifically designed for underground natural gas distribution
• Key Advantage: Flexible enough to pull through 2” conduit, rated for direct burial without additional protection

Sizing Options (all fit easily in 2” PVC conduit):

• 1/2” IPS (Iron Pipe Size) - OD ~0.84” - suitable for small loads
• 3/4” IPS - OD ~1.05” - typical residential service
• 1” IPS - OD ~1.31” - recommended for garage with heater + future appliances
• 1-1/4” IPS - OD ~1.66” - higher capacity if needed

Installation Method:

1. Through foundation: PE pipe pulled through 2” PVC protective sleeve using 125’ fish tape
2. Outside foundation: PE pipe continues direct buried from garage to house (no conduit needed)
3. At house connection: Transition to rigid pipe (steel/iron) using approved transition fittings

Burial Requirements:

• Depth: 18”-24” minimum (check local code), must be below frost line (36”-48” in Michigan)
• Deeper if needed: Under driveways or vehicle traffic areas may require greater depth
• Tracer wire: Yellow 12 AWG or 14 AWG copper wire must run alongside entire buried length
  • Allows future location with metal detector
  • Must be continuous and accessible at both ends
  • Usually brought up at garage and house ends for testing

Fittings and Connections:

• Heat fusion fittings: Most common and reliable method (requires specialized equipment)
• Mechanical compression fittings: Easier installation, more expensive
• Transition fittings: Required where PE connects to rigid pipe at house

Common Brands:

• Gastite FlashShield (PE with conductive layer)
• Performance Pipe Driscoplex
• Continental ContiTech
• Certa Lok (heat fusion system)

Code Compliance:

• MUST be installed by licensed gas fitter/plumber
• Requires permits and inspection
• Follow local gas codes and manufacturer specifications
• Pressure testing required after installation

Advantages:

• One continuous run from garage to house (no underground joints)
• Handles ground movement and settling well
• 50+ year service life
• Generally less expensive than CSST
• Same technology used by utility companies for gas service lines

Water Line (PEX)

Material: Underground-rated PEX tubing (ASTM F2023 standard)

• PEX-A or PEX-B rated for burial
• Typically 3/4” or 1” diameter for residential service

Installation Method:

• Pull through 2” PVC protective sleeve using fish tape
• Can run both supply and return if needed for circulation
• Direct burial outside foundation (though PVC sleeve provides extra protection)

Requirements:

• Must be buried below frost line (36”-48”)
• Avoid underground joints if possible
• Use proper fittings at connection points
• Consider insulation or heat trace in critical areas

Electrical Service

Conductors: THWN-2 or XHHW-2 rated wire

• Size depends on amperage requirements (typically 50A-100A subpanel for garage)
• Individual conductors or appropriate cable assembly
• Must meet NEC (National Electrical Code) requirements

Installation Method:

• Pull through 2” PVC conduit using fish tape
• Follow NEC conduit fill requirements
• May need multiple pulls or larger conduit depending on wire gauge/quantity

Requirements:

• Licensed electrician required
• Permit and inspection required
• Proper grounding and bonding
• GFCI protection as required by code

Low Voltage / Data

Recommended: Fiber optic for future-proof 10GbE+ connectivity

• Single-mode or multi-mode fiber (single-mode preferred for distance)
• LC or SC connectors
• Direct burial rated or in protective conduit

Alternative/Additional:

• Cat6A or Cat7 ethernet (rated for burial)
• Coaxial cable if needed
• Multiple cables can be pulled together in 2” conduit

Installation Method:

• Pull through 2” PVC conduit (easiest of all utilities)
• See homelab project documentation for detailed network implementation
• Terminate at network switch in garage, patch panel in house

Utilities to run or sleeve

• Electric service
• Natural gas
• Water/Sewer
• Low-voltage: buried conduit between house and garage for network/cable/phone/fiber. This will support a 10GbE fiber line to connect a switch in the garage and wireless AP in the upper floor. (See homelab project for detailed network implementation)

Sleeves and future-proofing

• Roof vent for future plumbing (install during build)
• ½” PEX conduit for future slab temperature sensor (10-14 ft into slab, 2” below surface, labeled “Sensor Conduit – Do Not Connect”) — see Decisions - Slab Sensor Conduit
• Consider adding sleeves or capped stubs for later: dryer vent, bath/kitchen exhaust, hose bibbs, mini-split line-set, solar PV conduit

Notes

• Capture PEX/tubing layout sketch and photos pre-pour.
• Keep utilities planned before driveway/cement to avoid rework.
• 2025-10-13 contract with Hershberger covers installing sleeves for sewer, water, electrical, and fiber; confirm routes and labeling before pour to ensure they land at mechanical room.
• 2025-10-20 update: Concrete contractor finished slab grading, forms, and rat wall trench; Hershberger team now needs to place floor foam, PEX, and underground conduits before inspection and pour.
• 2025-10-21 update: Hydronic in-floor materials now on site; plan review and protection before installation per Radiant Slab Materials Order.
• 2025-10-22 update: ✓ Under-slab insulation complete; ✓ PEX loops installed with manifold; ✓ Utility sleeves positioned (white PVC visible in foundation perimeter trench); ✓ Floor grading plan confirmed with contractor: lift bay will be level (optimal for lift installation), other 2 bays will be graded with shared central floor drain; ⧗ Pressure testing at 60-70 PSI in progress. Photos documented in Oct 22 aerial view, ground-level view, perimeter detail, PEX manifold, and pressure gauge.
• 2025-10-25 update: ✓ Mechanical inspection for PEX in-floor heating passed (Oct 23); ✓ Confirmed with Marcus that Terry (cement contractor) will install all utility conduits before concrete pour; Terry scheduled onsite Monday, Tuesday, or Wednesday this week (Oct 28-30) to complete conduit installation and pour concrete.
• 2025-10-29 update: ✓ Exterior perimeter insulation installation completed; ✓ Fiberglass rebar grid installation completed; Foundation preparation complete and ready for concrete pour; Comprehensive drone documentation captured (see DJI_0886.md through DJI_0891.md).
• 2025-10-30 update: ✓ All utility conduits successfully installed through foundation slab (1x 3” sewer, 4x 2” utilities for gas/water/electrical/low-voltage); ✓ Concrete foundation pour completed (cement truck arrival 1:24 PM); ✓ Finishing work in progress (expected completion end of day); Major construction milestone achieved with all embedded systems successfully integrated. Photo documentation: cement truck arrival, pour in progress, completed slab, conduits close-up, wide view. Real-time video (~1 hour): Construction Videos.

Related: 2025-09-05 - Site Staking - Marcus + Concrete · Lift

Venting and Terminations (from chat summary)

• Install a main 3” plumbing vent through roof during initial build (can be capped inside until tie-in).
• Prefer gable-end terminations for bath fan, dryer, and kitchen hood; each on its own duct with backdraft damper, spaced ≥3’.
• Dryer: rigid metal duct, length within code/manufacturer limits; terminate to exterior (not soffit/attic).
• Mini-split: provide exterior electrical box and a sleeve for refrigerant lines/drain.

Action Checklist

• Stub/sleeve: water, sewer, gas, electric, low-voltage before pour (main sleeves in contract; verify gas/low-voltage still included) — stage:: 2
• Install ½” PEX conduit for future slab temperature sensor (additional EZ Loop at manifold, 10-14 ft into slab, taped and labeled) — Blue PEX tube routed through EZ loop with in-floor heating lines — see Decisions - Slab Sensor Conduit — stage:: 2
• Add hose bibb rough-ins and exterior electrical box for mini-split — stage:: 3
• Leave conduit stubs for future data and solar — stage:: 2
• Verify floor drain locations and slope; coordinate drain piping to exterior (confirmed 2025-10-22: lift bay level, other 2 bays graded with shared central drain) — stage:: 2
• Pressure-test PEX before pour (verified and passed 24-hour hold) — stage:: 2
• Pressure-test PEX after pour — stage:: 2

Moved to related stages:

• Roof: see Roof for plumbing vent installation.
• Siding & Windows: see Siding for gable-end vent terminations.
• Exterior Lighting: see Lighting for switch neutrals and sensor conduit.