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Fairfax County Addition Permit Cost (2026)

Residential addition building permit fees in Fairfax County, Virginia, calculated under the Fairfax County Land Development Services Appendix Q FY2027 fee schedule (effective July 1, 2026). Fairfax County prices additions and enlargements per square foot of new floor area: $0.15 per sq ft for wood-frame construction (Type VA/VB), with a $141.75 minimum permit fee, plus the 2% Virginia state levy and the 10% Fairfax County technology surcharge, both calculated on the permit fee. The minimum all-in floor is $158.77 (covers wood-frame additions up to 945 sq ft). A 1,000 sq ft addition pays $168.00 all-in.

Building Permit
$0.15 per sq ft (wood frame)
Effective Rate Above 945 Sq Ft
$0.168 per sq ft all-in
Minimum All-In
$158.77 (up to 945 sq ft)
Levy + Technology Surcharge
2% + 10% of building permit fee
1,000 Sq Ft Addition All-In
$168.00
Fee Status
Verified Appendix Q FY2027
What This Guide Covers - and What It Does Not

This guide covers: Fairfax County residential addition building permit fees as published in the Fairfax County Land Development Services Appendix Q FY2027 fee schedule. Coverage includes the per-square-foot building permit rates by construction type (Appendix Q I-B(A) Table 1), the 2% Virginia state levy, the 10% Fairfax County technology surcharge, and the $141.75 minimum permit fee floor. "Addition" in Appendix Q includes room additions, sunrooms, and enclosed porches added to an existing dwelling footprint.

This guide does NOT cover: Zoning approvals (setback verification, lot coverage, RPA or floodplain overlays, FAR/Floor Area Ratio review). Site plan or grading review for footprint expansion. HOA architectural approvals. Trade permits (electrical, plumbing, HVAC) - these are billed separately under Fairfax's trade fee schedules. Stormwater management or land disturbance permits if the addition triggers them. Demolition of existing structure if the addition replaces a tear-down.

When a Fairfax addition permit is required: Land Development Services requires a building permit for any addition that adds enclosed habitable space, conditioned space, or that modifies the structural shell of the existing dwelling. Sunrooms, enclosed porches, screened porches converted to four-season rooms, dormers that add habitable space, and second-story additions all qualify. Like-for-like deck-to-screened-porch conversions still require a permit because the structural envelope changes. Verify directly with Land Development Services at (703) 222-0801 before assuming exemption.

Fee basis: Under Appendix Q FY2027, additions and enlargements are priced per square foot of new floor area by construction type (Table 1), not as a percentage of declared construction value. Wood frame (Type IIB/IIIB/VA/VB) is $0.15 per sq ft, Type IIA/IIIA/IV is $0.22 per sq ft, and Type IA/IB is $0.28 per sq ft, each subject to the $141.75 minimum permit fee. Almost every single-family addition in Fairfax is wood frame, so the figures on this page use the $0.15 rate.

Key Takeaways
  • Fairfax County uses one area-based formula across all residential additions: square feet of new floor area x $0.15 (wood frame, Type VA/VB) as the building permit fee, with a $141.75 minimum, plus the 2% Virginia state levy and the 10% Fairfax County technology surcharge, both applied to the permit fee. Above the minimum, all-in cost = sq ft x $0.15 x 1.12, or $0.168 per sq ft. There is no fee cap, so very large additions scale linearly with floor area.
  • For a 1,000 sq ft addition: $150.00 building permit + $3.00 state levy + $15.00 technology surcharge = $168.00. The arithmetic scales the same way at any floor area above 945 sq ft. At 2,000 sq ft: $300.00 + $6.00 + $30.00 = $336.00. At 3,000 sq ft: $450.00 + $9.00 + $45.00 = $504.00. The technology surcharge is the second-largest component after the per-square-foot permit fee.
  • Declared construction value does not drive the Fairfax addition permit fee. Appendix Q I-B(A) prices new buildings, additions and enlargements by floor area and construction type, so a $50,000 sunroom and a $150,000 sunroom of the same square footage pay the same permit fee. The construction-type rate is what changes the number: $0.22 per sq ft for Type IIA/IIIA/IV and $0.28 per sq ft for Type IA/IB, which almost never apply to a single-family addition.
  • Trade permits (electrical, plumbing, HVAC) are NOT included in the addition permit. Most Fairfax additions trigger all three trade categories - electrical for new outlets/lighting/circuits, plumbing if the addition includes a bathroom or kitchen extension, HVAC for the duct extensions or new zone. Trade permits add roughly $200-$800 to the addition permit total depending on installer scope. They are quoted at intake under separate trade fee schedules.
  • The minimum all-in floor is $158.77 ($141.75 minimum permit fee + $2.84 levy + $14.18 technology surcharge). It applies to any wood-frame addition up to 945 sq ft, because 945 x $0.15 = $141.75. That covers most bump-outs, sunrooms and single-room additions: a 400 sq ft addition calculates to $60.00 and an 800 sq ft addition to $120.00, and both are lifted to the $141.75 minimum.
  • Because the Fairfax fee is area-based with a low per-square-foot rate, it is now one of the cheaper addition permits in the verified Virginia cluster for typical scopes. A 500 sq ft heated addition pays $158.77 in Fairfax. Loudoun County charges a $395 bundle (building permit, plan review and county zoning permit) for additions of 1,000 sq ft or less, $395.00 to $399.60 with the levy (July 2022 schedule). Chesterfield County's flat-tier structure lands at $456.98. Henrico County's value-based formula gives $377.40 and Richmond City's $63 + $6.07/$1k formula gives $361.45. Only Virginia Beach's sq-ft formula ($196.70 for 500 sq ft heated) comes in lower.
  • Fairfax does not charge a separate plan review fee on residential additions. Most peer jurisdictions either bundle plan review (Richmond, Henrico) or charge a flat plan review fee ($25-$100, like Virginia Beach or Chesterfield); in Fairfax the filing fee paid at application is a deposit against the permit fee, not an added line. The 10% technology surcharge (Appendix Q Part III) is new for FY2027 and applies to the building permit fee.
  • The Appendix Q FY2027 fee schedule (amendment 05-26-Q, adopted May 5, 2026, effective July 1, 2026) was verified against fairfaxcounty.gov on September 18, 2026. It is the current published rate sheet on the Land Development Services portal. Always confirm current rates with Land Development Services at (703) 222-0801 before filing.
Calculate Your Addition Permit All Fairfax Permit Fees

Fairfax Addition Permit Fee Components

Every Fairfax County residential addition permit is built from three components: the per-square-foot building permit fee (Appendix Q I-B(A) Table 1, $141.75 minimum), the 2% Virginia state levy and the 10% Fairfax County technology surcharge, the last two both applied to the building permit fee.

Component Amount (1,000 sq ft example) How It Is Calculated
Building permit fee $150.00 1,000 sq ft x $0.15 per sq ft (wood frame, Type VA/VB). Minimum $141.75, which governs for additions up to 945 sq ft.
2% Virginia state levy $3.00 2% of the $150.00 building permit fee. Statutory under Code of Virginia §36-137 / USBC Section 107.2 (Appendix Q I-A.12).
10% Fairfax technology surcharge $15.00 10% of the $150.00 building permit fee. Fairfax County technology surcharge under Appendix Q Part III, new for FY2027.
All-in 1,000 sq ft addition total $168.00 $150.00 + $3.00 + $15.00. Trade permits, zoning approvals, and contractor work are excluded.

Source: Fairfax County Land Development Services Appendix Q Fee Schedule, FY2027, effective July 1, 2026, verified against fairfaxcounty.gov on September 18, 2026 by Munib Ur Rehman. Half of the permit fee is due at application as a filing-fee deposit and is credited toward the permit fee at issuance (County Code 61-1-3(d)11); it is not an extra charge and is not refunded if the application expires.

Worked Examples - Real Addition Projects in Fairfax County

Each example uses arithmetic from the Fairfax County Appendix Q FY2027 fee schedule. The permit fee is square feet of new floor area x $0.15 (wood frame), lifted to the $141.75 minimum when the calculation falls short; the 2% levy and 10% technology surcharge stack on top. Because the per-square-foot fee only exceeds the minimum above 945 sq ft, most single-room additions pay the $158.77 floor.

Example 1: 400 sq ft sunroom (wood frame, contractor cost about $50,000)

A homeowner adds a 400 sq ft enclosed sunroom on the rear of an existing dwelling. Construction type is wood frame (Type VB). The $50,000 contractor cost does not enter the fee.

  • Calculated rate: 400 x $0.15 = $60.00 (below the $141.75 minimum)
  • Building permit fee (minimum applies): $141.75
  • 2% Virginia state levy on $141.75: $2.84
  • 10% Fairfax technology surcharge on $141.75: $14.18
  • Total all-in addition building permit: $158.77

Trade permits (electrical for new outlets, plumbing if a sink moves, HVAC for the duct extension) are filed separately and add roughly $200-$400 to this total at intake.

Example 2: 800 sq ft family-room addition (wood frame, heated)

A homeowner builds an 800 sq ft heated family-room addition on the side of a single-family dwelling, wood frame construction.

  • Calculated rate: 800 x $0.15 = $120.00 (still below the $141.75 minimum)
  • Building permit fee (minimum applies): $141.75
  • 2% Virginia state levy on $141.75: $2.84
  • 10% Fairfax technology surcharge on $141.75: $14.18
  • Total all-in addition building permit: $158.77
Example 3: 1,000 sq ft second-story addition (wood frame, over existing garage and family room)

A homeowner adds a 1,000 sq ft second-story addition over an existing garage and family room, wood frame construction. This is the first common scope where the per-square-foot fee clears the minimum.

  • Building permit fee: 1,000 x $0.15 = $150.00
  • 2% Virginia state levy on $150.00: $3.00
  • 10% Fairfax technology surcharge on $150.00: $15.00
  • Total all-in addition building permit: $168.00
Example 4: 2,000 sq ft two-story addition (wood frame)

A homeowner builds a 2,000 sq ft two-story addition (1,000 sq ft per floor) on a single-family dwelling, wood frame construction.

  • Building permit fee: 2,000 x $0.15 = $300.00
  • 2% Virginia state levy on $300.00: $6.00
  • 10% Fairfax technology surcharge on $300.00: $30.00
  • Total all-in addition building permit: $336.00

Note: a second-story addition triggers structural review of the existing first-floor framing and footings. Appendix Q charges no separate plan review fee for the deeper structural review. Trade permits add another $400-$1,200 depending on bath/HVAC scope.

Calculate Your Fairfax Addition Permit

The PermitPrice fee calculator supports Fairfax's per-square-foot addition formula plus the 2% levy and 10% technology surcharge directly. Enter your addition's floor area and the calculator returns the all-in addition permit cost broken down by component.

Calculator coverage for Fairfax additions: the $0.15 per sq ft wood-frame rate + 2% Virginia state levy + 10% Fairfax technology surcharge. The minimum all-in floor of $158.77 is enforced for additions up to 945 sq ft. Trade permits are not modeled in the calculator.

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Fairfax Addition Permit Cost vs Other Verified Virginia Jurisdictions

Fairfax's FY2027 per-square-foot formula makes it one of the cheaper addition permits in the verified Virginia cluster for typical scopes. A 500 sq ft heated addition (about $50,000 declared) produces $158.77 in Fairfax versus $360-$500 in most value-based peer jurisdictions. Because Fairfax ignores declared value, the gap widens on high-cost additions and narrows only on very large floor areas.

Jurisdiction Addition Formula 500 Sq Ft / $50,000 Addition All-In
Fairfax County $0.15/sq ft (min $141.75) + 2% levy + 10% tech $158.77 (500 sq ft, minimum applies)
Loudoun County $395 bundle (1,000 sq ft or less) + the 2% levy, if not already included, on $230, July 2022 $395.00 to $399.60
Henrico County $100 + $6/$1k over $5k (capped $680) $377.40 (capped path)
Richmond City $63 + $6.07/$1k over $2k + 2% levy $361.45
Chesterfield County Flat tier $399 + $50 site + 2% levy $456.98 (flat-tiered)
Virginia Beach City $50 + $7/100 sq ft heated + $100 PR + 2% levy $196.70 (500 sq ft heated)

Comparison units differ: Richmond/Henrico use declared construction value; Loudoun uses a $395 bundle for additions of 1,000 sq ft or less (1% of value + $335 plan review + county zoning permit above that); Chesterfield uses a flat-tier scheme; Fairfax and Virginia Beach use sq ft. Trade permits are excluded from every row. The 500 sq ft heated addition assumed in the Fairfax and Virginia Beach rows is the closest like-for-like proxy at the $50,000 declared value level. Virginia requires a 2% state levy on building-code permit fees (USBC Section 107.2), but Loudoun's published fees do not say whether that levy is already included or whether it is charged on plan review, so PermitPrice shows each Loudoun total as a range: the published amount up to 2% more on the building permit and plan review portion (the levy never applies to the zoning permit).

Side-by-Side Math

For full breakdowns of how Fairfax compares against neighboring jurisdictions on additions, decks, and pools, see the dedicated comparison pages.

Frequently Asked Questions

A Fairfax County residential addition building permit costs $0.15 per sq ft of new floor area (wood frame) as the building permit fee with a $141.75 minimum, plus the 2% Virginia state levy and the 10% Fairfax technology surcharge on the permit fee. Any wood-frame addition up to 945 sq ft pays the $158.77 minimum all-in. A 1,000 sq ft addition pays $168.00. A 2,000 sq ft addition pays $336.00. A 3,000 sq ft addition pays $504.00. Trade permits (electrical, plumbing, HVAC) are billed separately and add roughly $200-$1,200 depending on installer scope.
Per Fairfax County Appendix Q, "addition" includes room additions, sunrooms, enclosed porches added to existing footprint, second-story additions, dormers that add habitable space, and bump-outs. The defining test is whether the project adds enclosed habitable or conditioned space, or modifies the structural shell of the existing dwelling. Decks, fences, sheds, and accessory structures are billed under their own Appendix Q line items, not the addition formula. Screened porches (open to outdoor air on three sides) are typically billed as an addition because the structural envelope still gets reviewed.
Fairfax stacks three components, but the base is small: $0.15 per sq ft of new floor area (wood frame) with a $141.75 minimum, and the 2% Virginia levy plus the 10% Fairfax technology surcharge on the permit fee. That works out to $0.168 per sq ft above 945 sq ft, and a flat $158.77 below it. Richmond uses a value-based bundled formula at $63 + $6.07/$1,000 (effective ~0.7% of declared value), and Henrico's value-based formula caps at $680 + 2% levy = $693.60. Because a typical addition costs well over $100 per sq ft to build, a value-based fee usually lands higher than Fairfax's area-based fee. The differences come from each schedule's structure, not from inspection quality.
It would not help. Under Appendix Q FY2027 the addition permit fee is based on square feet of new floor area and construction type (I-B(A) Table 1), not on declared construction value, so the cost you state on the application does not change the fee. Understating the floor area is not a strategy either: Land Development Services reviews the plans, and the area on the approved drawings is what the permit is issued against. Misstating scope triggers a desk review and delays the permit.
No. Trade permits are filed separately under Fairfax's trade fee schedules and are not included in any number on this page. Most additions trigger all three trade categories: electrical for new outlets/lighting/circuits, plumbing if the addition includes a bathroom or kitchen extension or relocation, HVAC for the duct extensions or new zone equipment. Trade permits add roughly $200-$1,200 to the addition permit total depending on installer scope, fixture count, and equipment count. The licensed trade contractors pull these permits separately at intake.
Yes. Fairfax County Land Development Services routes addition applications through Zoning Administration before building plan review can issue. Setback verification, lot coverage, FAR (Floor Area Ratio), Resource Protection Area (RPA), and floodplain overlays are all checked at zoning. Zoning approval can take 2-4 weeks for straightforward setback questions and longer for RPA, FAR, or special-exception cases. The Appendix Q building permit fees on this page do not include any zoning fees - those are separate and quoted at zoning intake.
Per Fairfax County refund policy, the filing-fee deposit paid at application (half the permit fee) is not refunded if the application expires or is withdrawn after plan review begins. The building permit fee is refundable in part if the permit was issued but no inspections were performed - typically half. The 2% Virginia state levy and the 10% technology surcharge are not refundable. The exact refund schedule depends on which milestones the application reached. Confirm directly with Land Development Services before cancelling and ask for a written refund quote.
No. The $168.00 Fairfax addition permit fee (for 1,000 sq ft) is the County building permit cost only - the cost to apply, get plan review, and have inspections performed. It does not include any contractor work. A 300-400 sq ft sunroom installed in the Fairfax market typically runs $40,000-$80,000 for the contractor scope (foundation, framing, windows, roofing, finishes, labor). A 500 sq ft heated family-room addition runs $80,000-$150,000+. The permit fee is a very small line item in your overall addition project budget; the bulk is contractor scope. PermitPrice tracks only the County permit fee component.

Sources

Official .gov Sources - Verified September 2026
  • Fairfax County Land Development Services Appendix Q Fee Schedule (FY2027) Appendix Q FY2027, effective July 1, 2026 (amendment 05-26-Q, adopted May 5, 2026) - Fairfax County Land Development Services - Primary source for the per-square-foot addition rates by construction type (I-B(A) Table 1), the $141.75 minimum permit fee (I-A.1), the filing-fee deposit (I-B(G)), the 2% levy (I-A.12) and the 10% technology surcharge (Part III). Verified September 18, 2026 Verified FY2027
  • Fairfax County Land Development Services Accessed September 18, 2026 - Land Development Services Department - Index page linking the published fee schedule, application forms, online portal (PLUS), and inspection scheduling. Phone (703) 222-0801
  • Code of Virginia Section 36-137 - USBC State Levy Authority Current - Virginia General Assembly - Authorizing statute for the statewide 2% building permit surcharge applied across all Virginia jurisdictions, including Fairfax County addition permits
Next Step

Calculate your specific Fairfax addition permit cost, see all Fairfax fee categories, or compare against neighboring jurisdictions.

Always verify current addition permit fees directly with Fairfax County Land Development Services before budgeting or filing. The Appendix Q FY2027 fee schedule (effective July 1, 2026) on fairfaxcounty.gov is the most recent posted as of September 18, 2026. Call (703) 222-0801 or visit the Land Development Services portal to confirm addition permit rates, construction-type classification, and zoning approval status before submitting an application.
Disclaimer: All fee information on PermitPrice is for informational purposes only and is not an official permit quotation. Actual permit fees are determined by Fairfax County Land Development Services at the time of application. Addition fees are based on the floor area and construction type shown on the approved plans. Trade permit costs (electrical, plumbing, HVAC) are not modeled in this guide and depend on installer scope. Zoning fees, site plan review fees, and stormwater permits are separate from Appendix Q building permit fees. Verify directly with Land Development Services before filing.

Written by: Munib Ur Rehman

Data verified against official fee schedule documents.