How room addition permits work in Herriman
The permit itself is typically called the Residential Building Permit — Addition.
Most room addition projects in Herriman pull multiple trade permits — typically building, electrical, plumbing, and mechanical. Each is reviewed and inspected separately, which means more checkpoints, more fees, and more coordination between the trades on the job.
Why room addition permits look the way they do in Herriman
Herriman sits in an Earthquake-Prone zone on the Wasatch Front requiring SDC-D seismic design on most new residential structures. Expansive bentonite clay soils in many subdivisions require engineered foundations — grading and soils reports are routinely required. Rapid subdivision growth means many lots are still platted as new developments, requiring project-specific dry-utility coordination with Rocky Mountain Power and Dominion. Wildland-Urban Interface (WUI) fire codes apply across much of the city's southern and western foothills.
For room addition work specifically, the structural specifications are shaped by local conditions: the city sits in IECC climate zone CZ5B, frost depth is 30 inches, design temperatures range from 8°F (heating) to 95°F (cooling). Post and footing depths typically need to extend at least 30 inches to clear the frost line.
Natural hazard overlays in this jurisdiction include earthquake seismic design category D, expansive soil, radon, wildfire, and FEMA flood zones. If your address falls within any of these overlay zones, the room addition permit application picks up an extra review step that can add days to the timeline and specific design requirements to the plans.
HOA prevalence in Herriman is high. For room addition projects this matters because HOA architectural review committee approval is a separate process from the city building permit, and the two have completely different rules. The HOA reviews materials, colors, and aesthetics; the city reviews structural, electrical, and code compliance. You generally need both, and the HOA approval typically takes 2-4 weeks regardless of how fast the city is.
What a room addition permit costs in Herriman
Permit fees for room addition work in Herriman typically run $800 to $3,500. Valuation-based; typically calculated as a percentage of project valuation using Salt Lake County or ICC building valuation data tables, plus a separate plan review fee (often 65% of permit fee)
Utah imposes a state construction services commission surcharge; Herriman may also charge a technology/document fee; plan review billed separately and non-refundable even if permit is denied.
The fee schedule isn't usually what makes room addition permits expensive in Herriman. The real cost variables are situational. Geotechnical soils report required due to expansive bentonite clay soils — typically $1,500–$3,000 before design begins. SDC-D seismic structural engineering package (stamped PE drawings, hold-down schedules) adds $2,000–$4,000 to soft costs. IECC 2021 CZ5B envelope requirements mandate R-20 walls and R-49 ceilings, pushing insulation and framing costs above national averages. 30-inch frost depth requires deeper footings than most of the country, increasing concrete and excavation costs especially in rocky Oquirrh foothills soils.
How long room addition permit review takes in Herriman
10-20 business days for initial plan review; corrections cycle adds 5-10 business days per resubmittal. There is no formal express path for room addition projects in Herriman — every application gets full plan review.
What lengthens room addition reviews most often in Herriman isn't department slowness — it's resubmissions. Each correction round generally puts the application back in the queue, so first-pass completeness matters more than first-pass speed.
Three real room addition scenarios in Herriman
What the rules look like in practice depends a lot on the specific situation. These three scenarios cover the common shapes of room addition projects in Herriman and what the permit path looks like for each.
Utility coordination in Herriman
Rocky Mountain Power (1-888-221-7070) must be contacted for any service panel upgrade or new sub-panel in the addition; Dominion Energy Utah (1-800-323-5517) coordinates gas line extension or new appliance drops — both are separate from the building permit and can extend project timelines 2-6 weeks.
Rebates and incentives for room addition work in Herriman
Some room addition projects qualify for utility rebates, state energy program incentives, or federal tax credits. The most relevant programs in this jurisdiction are listed below — eligibility depends on equipment efficiency ratings, contractor certification, and post-installation documentation, so verify specifics before purchasing.
Rocky Mountain Power wattsmart — Insulation Rebate — $100–$400. Added attic insulation to R-49+ or wall insulation upgrades in the addition envelope. wattsmart.com
Dominion Energy Utah High-Efficiency Furnace Rebate — $100–$300. 96%+ AFUE gas furnace installed to serve addition or whole-home upgrade triggered by addition load. dominionenergy.com/savings
Federal IRA 25C Energy Efficiency Tax Credit — Up to $1,200/year. Qualifying insulation, windows (U≤0.30 for CZ5B), and HVAC in the addition; keep manufacturer certifications. irs.gov/credits-deductions
The best time of year to file a room addition permit in Herriman
Herriman's 30-inch frost depth and CZ5B winters make footing and foundation work risky November through March; the ideal construction window is May through October, though summer permit demand peaks June–August, stretching review timelines by 1-2 weeks.
Documents you submit with the application
For a room addition permit application to be accepted by Herriman intake, the submission needs the documents below. An incomplete package is returned without going into the review queue at all.
- Site plan showing addition footprint, setbacks from all property lines, and existing structure
- Architectural floor plans and elevations stamped by licensed designer or engineer
- Structural engineering package with seismic (SDC-D) and gravity load calculations, stamped by Utah-licensed PE
- Geotechnical/soils report addressing expansive soil conditions and foundation recommendations
- IECC 2021 energy compliance documentation (ResCheck or equivalent) covering the addition envelope
Who is allowed to pull the permit
Homeowner on owner-occupied with signed owner-builder acknowledgment; licensed contractor for trade sub-permits (electrical, plumbing, HVAC must be state-licensed per DOPL)
Utah DOPL General Contractor B100 for primary permit; S210/S220 Electrical, S270/S280 Plumbing, S340 HVAC for respective trade permits — all verified at dopl.utah.gov
What inspectors actually check on a room addition job
A room addition project in Herriman typically goes through 4 inspections. Each inspector has a specific checklist, and the difference between a same-day pass and a re-inspection (which costs typically $75–$250 in re-inspection fees plus another scheduling delay) usually comes down to one or two items on these lists.
| Inspection stage | What the inspector checks |
|---|---|
| Footing / Foundation | Footing depth minimum 30 inches below grade, width per engineer spec, soils condition matching geotech report, rebar placement and grade, seismic anchor bolt layout per structural plans |
| Framing / Rough-in | Structural framing per stamped plans including seismic hold-downs and shear wall nailing schedule, rough electrical, plumbing, and HVAC before insulation or drywall closure |
| Insulation / Energy | Wall cavity insulation R-value, ceiling insulation depth, continuous air barrier, window U-factor labels matching approved plans per IECC 2021 CZ5B requirements |
| Final | Egress compliance for any new bedroom, smoke/CO alarm interconnection with existing system, exterior weather barrier and flashing at addition-to-existing junction, all trade finals signed off |
Re-inspection is straightforward when corrections are minor — a missing GFCI receptacle, an unsealed penetration, a label that wasn't applied. It becomes painful when the correction requires re-opening recently-closed work, which is the worst-case scenario specific to room addition projects and the reason rough-in stages get the most scrutiny from Herriman inspectors.
The most common reasons applications get rejected here
The Herriman permit office sees the same patterns over and over. These specific issues account for most first-pass rejections, and most of them are entirely preventable with a few minutes of double-checking before submission.
- Structural plans missing seismic hold-down hardware details or shear wall nailing schedule required for SDC-D
- Footing depth or width not matching geotechnical report recommendations for expansive soil conditions
- Egress window in new bedroom failing 5.7 sf net openable area or exceeding 44-inch sill height per IRC R310
- Smoke and CO alarms not interconnected with the existing dwelling's alarm system per IRC R314/R315
- Envelope insulation R-values or window U-factor not meeting IECC 2021 CZ5B minimums on energy compliance doc
Mistakes homeowners commonly make on room addition permits in Herriman
The patterns below come up over and over with first-time room addition applicants in Herriman. Most of them are rooted in assumptions that work fine in other jurisdictions but don't here.
- Assuming a design-build contractor's quote includes the geotechnical report and engineering stamp — these are almost always billed separately and can blindside homeowners by $4,000–$7,000
- Submitting for permit before obtaining HOA architectural approval; Herriman's high HOA prevalence means the city will issue the permit but HOA can still stop construction, creating costly conflicts
- Underestimating the HVAC resizing requirement — adding even 400 sf in CZ5B at 5,000 ft elevation typically requires a Manual J recalculation and often a new or upsized HVAC unit, not just extended ductwork
- Skipping the radon rough-in passive system during slab pour for the addition, then paying substantially more to retrofit it after drywall is closed
The specific codes that govern this work
If the inspector cites a code section, this is the list they'll most likely be referencing. These are the live code references that Herriman permits and inspections are evaluated against.
IRC R301.2 and ASCE 7-16 (seismic design SDC-D requirements for Wasatch Front zone)IRC R303 (light, ventilation, and heating requirements for new habitable rooms)IRC R310 (egress window requirements for any new bedroom)IRC R314 / R315 (smoke and CO alarm placement throughout updated dwelling)IECC 2021 R402.1 (envelope insulation: walls R-20, ceiling R-49 typical for CZ5B)IRC R403.1 (footings below frost depth — 30-inch minimum in Herriman)
Utah has adopted the 2021 IBC/IRC with state amendments; Herriman follows Salt Lake County radon-resistant construction provisions requiring passive radon mitigation rough-in for all new slab or below-grade work. WUI fire code (IRC Chapter 3 Appendix WA or local equivalent) applies to additions in the southern/western foothills fire-hazard zones.
Common questions about room addition permits in Herriman
Do I need a building permit for a room addition in Herriman?
Yes. Any structural addition to a dwelling in Herriman requires a building permit. This includes all attached room additions regardless of size, as they involve foundation work, framing, electrical, and envelope changes.
How much does a room addition permit cost in Herriman?
Permit fees in Herriman for room addition work typically run $800 to $3,500. The exact fee depends on the project valuation and which trade subcodes apply. Plan review and re-inspection fees are sometimes assessed separately.
How long does Herriman take to review a room addition permit?
10-20 business days for initial plan review; corrections cycle adds 5-10 business days per resubmittal.
Can a homeowner pull the permit themselves in Herriman?
Yes — homeowners can pull their own permits. Utah allows owner-builders to pull their own permits for owner-occupied single-family residences, with signed owner-builder acknowledgment forms typically required. Subcontractors (electrical, plumbing, HVAC) must still be licensed.
Herriman permit office
Herriman City Building Department
Phone: (801) 446-5323 · Online: https://herriman.utah.gov
Related guides for Herriman and nearby
For more research on permits in this region, the following guides cover related projects in Herriman or the same project in other Utah cities.