Austin Home Addition — DSD Permits, Tree Code, Floodplain, $80K-$900K

Austin is one of the most procedurally intricate cities in Texas for home additions — not because the rules are hidden, but because they stack. A single 900-square-foot rear addition in a Hyde Park bungalow can trigger Development Services Department (DSD) plan-check, Historic Landmark Commission review, Chapter 25-8 tree protection, Chapter 25-2 zoning compliance, Austin Energy Code requirements, and — if the lot edges the floodplain — Federal Emergency Management Agency elevation certification. Any one of those, missed early, resets the project by months.

This pillar is the institutional reference for Austin homeowners adding 500-2,500 square feet to an existing house. It is distinct from our Austin HOME Initiative and ADU pillar¹; if you are building a detached accessory dwelling unit, converting a garage into a living unit, or using the City's HOME amendments, read that one first. This one covers the typical additive scenario: expanding the primary residence itself — a second story over an existing one-story, a rear family room, a wrap-around to add a master suite and expanded kitchen, or a combined garage conversion plus additional conditioned space.

Angi sends your information to 12 strangers. Baily sends it to one Texas Department of Licensing and Regulation (TDLR) sub-trade-verified contractor with documented Austin DSD plan-check experience and, where relevant, heritage district track record.

Texas no-state-GC reality (referenced from /austin/home-initiative-adu)

Texas does not issue a statewide comprehensive general contractor license. There is no direct equivalent to California's Contractors State License Board (CSLB) or Arizona's Registrar of Contractors (ROC). A homeowner who assumes "licensed in Texas" means a single credential will verify a contractor has discovered — sometimes painfully — that the verification stack is actually distributed across five separate sources.

For Austin home additions, the verification stack Baily enforces before any contractor match is:

• TDLR (Texas Department of Licensing and Regulation) credentials for regulated sub-trades — electrical contractors, HVAC/refrigeration, elevator, and related specialties are all TDLR-licensed at the state level².
• Texas State Board of Plumbing Examiners (TSBPE) — plumbing is regulated separately under its own board, not TDLR.
• Texas Workers' Compensation Act (TWCA) coverage — Texas is a non-subscriber state, but any contractor your project touches should carry workers' comp or equivalent occupational accident coverage with documented proof.
• Certificate of Insurance (COI) with general liability appropriate to project value (typically $1M per occurrence / $2M aggregate minimum for residential additions in the $200K+ range) plus auto coverage.
• City of Austin contractor registration — separate from state credentials. Austin requires municipal registration for contractors pulling permits through DSD, and some trade categories require additional local endorsements.

A contractor claiming to be "Austin licensed" without producing the TSBPE plumber number for their plumbing sub, the TDLR electrical contractor number for their electrical sub, the city contractor registration for themselves, and a current COI naming the homeowner as an additional insured is presenting an incomplete credential set. The full explanation of how Texas structures this lives in our companion pillar¹; this pillar assumes that groundwork.

City of Austin Development Services Department (DSD) permit process

DSD is the single permitting authority for residential additions within the City of Austin. Unincorporated Travis County properties (some parcels in Bee Cave, West Lake Hills, Rollingwood, and portions of unincorporated areas north and east of the city limits) follow different processes, so the first thing to verify is which jurisdiction governs your parcel.

Within DSD, the permit path for a home addition runs through two portals:

• AB+C (Austin Build + Connect) — the primary online permitting system, used for application submission, document upload, fee payment, plan-check review tracking, and inspection scheduling³.
• BuildAustin — the public-facing project status portal where homeowners and their teams can track where a permit sits in review.

For any addition over approximately 500 square feet, DSD recommends — and for many projects effectively requires — a pre-development coordination meeting before formal submittal. This meeting surfaces tree protection concerns, floodplain implications, heritage overlay requirements, drainage review triggers, and zoning compliance questions before plan-check fees are paid and the formal clock starts. Skipping the pre-development meeting on a complex addition is one of the single most common ways Austin projects enter a plan-check cycle, receive comments, revise, resubmit, receive more comments, and stretch from a 6-week review into a 14-week review.

Plan-check timelines at DSD for a typical residential addition currently run 6 to 14 weeks depending on:

• Project complexity (straight rear addition vs. second-story addition with structural re-engineering of the existing ground floor)
• Whether tree protection review is triggered (adds 4-8 weeks running in parallel)
• Whether floodplain review is required (adds 6-12 weeks in parallel)
• Whether the property sits in a Heritage Conservation District or affects a Historic Landmark (Landmark Commission review runs on its own calendar)
• Initial submission completeness — incomplete submittals add review cycles

DSD also coordinates with Austin's 3-1-1 community concerns process. Neighbors can raise concerns about projects affecting their property, and large additions in dense neighborhoods sometimes receive informal scrutiny through this channel even when no formal public-hearing trigger applies.

Permit categories (SFR addition + MEP + tree + drainage + floodplain)

An Austin home addition of any meaningful size pulls, at minimum, a single-family residential building permit. But that is rarely the only permit the project needs. The full category stack for a typical 1,000-square-foot addition is:

• Single-Family Residential (SFR) Addition Permit — the primary structural permit authorizing the expansion of the conditioned building envelope. Covers structural framing, foundation, exterior envelope, roofing, and connection to the existing structure.
• Mechanical / Electrical / Plumbing (MEP) sub-permits — these are sometimes issued under a combined permit, sometimes as separate sub-permits. Required for any new HVAC equipment, any new electrical circuits or panel upgrades, and any new plumbing fixtures or relocated lines. Larger additions frequently require panel service upgrades to handle additional load.
• Tree Protection Permit — required for any construction activity within the critical root zone of a protected tree, or for any protected or heritage tree removal (see Chapter 25-8 section below).
• Drainage Permit — for additions that meaningfully change the site's impervious cover or drainage pattern. Generally triggered when an addition exceeds 500 square feet of new impervious area or when roof drainage is being redirected in a way that affects neighboring properties.
• Floodplain Development Permit — required for any work on a property where any portion of the parcel falls within the 100-year or 500-year floodplain per the City of Austin Floodplain Maps⁴. This is separate from and in addition to the building permit.
• Driveway / Right-of-Way Permits — if the addition changes the driveway configuration, adds a new curb cut, or temporarily uses the public right-of-way during construction.

Austin does not bundle all of these into a single review. Each permit category has its own reviewer, its own cycle time, and its own comment/resubmittal loop. A project that attempts to submit the SFR addition permit without flagging the tree, floodplain, or drainage components up front will discover those issues mid-review and restart clock segments.

Austin zoning + setback + FAR + lot coverage

Austin's land development code (Chapter 25-2) is one of the more complex zoning frameworks in Texas, with more than 100 specific land use combinations codified into base districts, overlays, and conditional overlays⁵. For home additions, the categories that matter most are the single-family residential base zones:

• SF-3 — the most common single-family zone in Austin. Allows single-family plus duplex, with the HOME Initiative amendments enabling additional units on qualifying lots (covered in the companion pillar).
• SF-2 — single-family standard, typical in older neighborhoods.
• SF-4A / SF-4B — small-lot single-family, denser configurations.
• SF-5 — urban family residence, typically small lots near the urban core.
• SF-6 — townhouse and condominium residence.

Typical single-family zone requirements affecting additions include:

• Setbacks — front setbacks are usually 25 feet, side setbacks range from 5 to 10 feet depending on zone and lot width, rear setbacks are typically 10 to 25 feet. Heritage district overlays often impose additional setback requirements to preserve historic streetscape rhythms.
• Lot coverage — the maximum percentage of the lot that can be covered by buildings (including the existing house plus any addition) typically caps at 40% to 50% for single-family zones. This is one of the most frequently hit limits on aggressive rear additions.
• Floor-Area Ratio (FAR) — the ratio of total conditioned floor area to lot area. SF-3 commonly runs at 0.4 to 0.6 FAR. A large 2,500-square-foot addition to a 1,800-square-foot house on a 7,000-square-foot lot may exceed FAR even if setbacks and lot coverage comply.
• Height limits — typically 32 to 35 feet for single-family zones, with heritage districts and compatibility standards imposing additional height and mass restrictions near one-story neighbors.
• Compatibility standards — Austin's compatibility rules constrain what can be built near single-family zoned lots, affecting some addition configurations.

Any addition design should start with a zoning analysis pulled against the specific parcel's base zone and every overlay applied to it. A survey or civil drawing showing existing conditions, proposed conditions, all setbacks measured, lot coverage calculated, FAR calculated, and impervious cover calculated is the foundation document for any Austin addition.

Heritage Conservation Districts (Hyde Park / Bouldin / Old West Austin)

Austin has multiple neighborhood areas where historic preservation overlays apply additional review to exterior work on contributing structures. The most commonly encountered include:

• Hyde Park — National Register Historic District with local heritage overlay. Contributing structures require Historic Landmark Commission review of exterior additions visible from the public right-of-way.
• Old West Austin — combines several sub-neighborhoods (Enfield, Pemberton Heights, Tarrytown, Clarksville in part) under varying preservation frameworks.
• Bouldin Creek — National Register Historic District, growing historic overlay enforcement.
• Old East Austin — including portions of Chestnut, Rogers-Washington-Holy Cross, and adjacent neighborhoods with historic overlay frameworks.

The review process generally uses tiered staff-to-commission escalation:

• Minor / administrative review — small additions, rear additions not visible from the primary street, and certain in-kind exterior work can be approved at the staff level.
• Mid-tier review — moderate additions, significant changes to visible elevations, or work on contributing structures that substantially affects the historic character typically require Historic Landmark Commission review⁶.
• Major review — large additions, additions to Historic Landmarks, demolition of contributing structures, or high-impact visible changes receive full public hearing review.

The critical design principle in heritage districts is that additions should be subordinate to, compatible with, and differentiable from the original historic structure. A second-story addition that overwhelms the original bungalow, or a rear addition using materials and fenestration patterns entirely foreign to the era and style of the original, will receive staff comments or commission objections.

For homeowners in any of Austin's heritage areas, engaging the project team before design starts — rather than after — is the difference between a 3-month permit cycle and a 9-month permit cycle.

Tree Protection Ordinance Chapter 25-8 (the 19" DSH trap)

Austin's Tree Protection Ordinance, codified at Austin Code Chapter 25-8, is among the most stringent urban tree protection frameworks in Texas and frequently catches addition projects off guard⁷.

The thresholds:

• Protected Size Class — any tree of a protected species measuring 19 inches or larger in diameter at standard height (DSH, measured 4.5 feet above grade on the uphill side of the tree) is a protected tree. Removal, severe pruning, or construction damage requires a permit and often mitigation.
• Heritage Size Class — any protected-species tree measuring 24 inches or larger DSH is a heritage tree. Removal requires extensive justification, Board of Adjustment variance in some cases, and significant mitigation.

The protected species list includes many common Central Texas natives — live oak, post oak, bur oak, pecan, cedar elm, bald cypress, and others. A mature live oak in an Austin yard almost always exceeds the 19-inch DSH threshold and frequently exceeds the 24-inch heritage threshold.

The Critical Root Zone (CRZ) concept is where most addition projects discover tree issues:

• CRZ radius is calculated at approximately 0.5 foot of radius per 1 inch of DSH (with city-specific refinements per the ordinance). A 24-inch heritage live oak has roughly a 12-foot CRZ radius — a 24-foot-diameter protected area.
• No construction activity — no trenching, no foundation work, no grade change, no heavy equipment access, no material storage — is permitted within the CRZ without specific mitigation approvals.
• A rear addition envelope that extends within the CRZ of a heritage oak may be permissible only with tunneling foundations, root-protective grade treatments, and arborist-supervised construction — or may be infeasible without removal, which requires its own variance process.

Penalties for unpermitted tree removal or CRZ violation are significant — fines can reach thousands of dollars per inch of DSH of the damaged tree, and required mitigation plantings can multiply the project's landscape budget. A homeowner who clears a tree "to make room" before a permit is issued has created a compliance problem that will follow the addition through plan-check and beyond.

Baily's Austin pre-match checklist includes a preliminary site-tree review: if there are mature trees anywhere near the proposed addition envelope, a certified arborist's report should exist before design is finalized.

Floodplain considerations + 1 ft above BFE

Austin has substantial floodplain exposure. Portions of East Austin along creeks and drainages, areas around Barton Creek, Shoal Creek, Waller Creek, Walnut Creek, sections of Bouldin adjacent to drainage corridors, and various lake-adjacent parcels fall within the 100-year or 500-year floodplain per City of Austin and FEMA mapping⁴.

For an addition on a floodplain parcel, the requirements compound:

• Floodplain Development Permit — required for any work on a floodplain parcel, including the proposed addition.
• Base Flood Elevation (BFE) — the elevation the 100-year flood is expected to reach. For any new finished floor in a Special Flood Hazard Area, Austin typically requires at least 1 foot of freeboard above BFE (finished floor must be at least BFE + 1.0 foot).
• Elevation Certificate — prepared by a licensed surveyor, documenting the relationship of the proposed and existing finished floors to BFE.
• Compensatory storage — if the addition reduces floodplain storage capacity (by filling, by enclosed construction below BFE, by displacing flood volume), the project must provide equivalent compensatory storage elsewhere on the parcel.
• Substantial improvement rule — if the cost of the addition plus any other improvements in a given period exceeds 50% of the pre-improvement market value of the structure, the entire structure may be required to be brought into full floodplain compliance — which for an older low-elevation home can be financially catastrophic to the project.

Insurance implications are not trivial. Properties in the 100-year floodplain are generally required to carry flood insurance if they have a federally backed mortgage, and addition work can change premium calculations. Homeowners considering additions on parcels with any floodplain exposure should pull the floodplain determination and have a structural and civil review before committing to design.

Drainage + impervious cover requirements

Even outside the floodplain, Austin treats site drainage as a permit-review concern for any meaningful addition. The key constraints:

• Impervious cover limits — typically 45% for SF-3, varying by zone and overlay. Impervious cover includes the primary residence footprint, addition footprint, driveways, patios, pool decks, and any other non-permeable surface. Aggregate impervious cover is calculated as a percentage of total lot area.
• Impervious cover over a threshold — additions exceeding 500 square feet of new impervious area, or projects crossing specific lot-coverage or impervious-cover thresholds, trigger formal drainage analysis requiring a licensed engineer.
• Stormwater management — for larger impervious additions, on-site stormwater retention, detention, or permeable treatment may be required.
• Roof drainage — downspouts and roof drainage patterns must be directed to appropriate receiving areas. Drainage that discharges onto neighboring properties is a frequent 3-1-1 complaint source and a common plan-check correction.
• Grading and drainage plan — required for any project that meaningfully changes site topography.

A 1,200-square-foot rear addition on an already-developed Austin lot frequently pushes total impervious cover to or past the 45% limit, triggering either a design reduction, a permeable-paving strategy for driveways and walkways, or a formal drainage variance request.

Common Austin addition patterns (2nd-story / rear / wrap-around)

The five most common Austin home addition configurations and their typical issue profile:

Second-story addition over existing one-story

• Structural re-engineering of ground-floor walls and foundation is usually required
• Height-limit and compatibility-standard compliance becomes critical, especially in older neighborhoods with one-story character
• Heritage district review often intensive because second-story additions dramatically change street-facing mass
• Energy code implications substantial — entire envelope may upgrade under code
• Construction cost premium of 30% to 50% over a ground-floor addition of the same square footage

Rear addition — family room, master suite, kitchen expansion

• Most common addition type, typically the lowest-complexity pattern
• Tree protection is the most common trap — rear additions frequently collide with mature oaks
• Impervious cover and rear-setback limits are the next most common traps
• Drainage review frequently triggered

Wrap-around addition combining side and rear

• Side-setback compliance is the primary constraint
• Lot-coverage limits often hit
• FAR can become binding on smaller lots
• Heritage compatibility issues with visible side elevations

Garage conversion plus main-house addition combined

• The garage conversion component overlaps the HOME Initiative / ADU framework covered in the companion pillar
• The main-house addition component follows standard SFR addition procedure
• Parking replacement requirements may apply — if the garage was providing required off-street parking, the project may need to provide replacement parking

Pool house / casita as separate structure

• Functions as a separate detached structure rather than an addition to the primary residence
• Often overlaps ADU rules (read the companion pillar)
• Tree protection and setback issues similar to primary-residence additions
• Impervious-cover and FAR calculations include the new detached structure

Cost bands $80K-$900K by scope

Austin addition costs run wide, and the wide-range numbers circulating online (e.g., "$200-$400 per square foot") obscure real cost drivers. A realistic 2026 cost framework for Austin home additions:

• Light addition — 200 to 500 square feet, no structural complexity, straightforward finishes, no heritage or floodplain compliance: $80,000 to $180,000, roughly $300-$400 per square foot all-in.
• Mid-range addition — 500 to 1,200 square feet, meaningful kitchen or master suite component, mid-tier finishes, some structural re-engineering: $180,000 to $400,000, roughly $325-$450 per square foot.
• Major addition — 1,200 to 2,500 square feet, significant structural changes, premium finishes, second-story component or complex wrap-around: $400,000 to $900,000, roughly $350-$500 per square foot.
• Premium heritage addition — Tarrytown, West Lake Hills-adjacent, Old West Austin, high-compliance heritage district work, architect-intensive design, high-end finishes, tree and floodplain compliance: $400 to $700+ per square foot all-in.

Cost drivers that materially move the number:

• Tree protection mitigation (arborist oversight, tunneling foundations, protective fencing throughout construction) adds $10K-$40K on tree-constrained lots.
• Floodplain compliance (elevation, compensatory storage, drainage engineering) adds $20K-$80K on floodplain parcels.
• Heritage district compliance (custom windows, matching siding profiles, review-cycle cost) adds $30K-$100K on contributing structures.
• Austin Energy service upgrades (panel upsizing, service-entrance work) add $5K-$25K when load-analysis triggers upgrades.
• Second-story structural re-engineering adds a 30%-50% premium over ground-floor addition baselines.

Timeline 8-18 months total

A realistic end-to-end timeline for an Austin home addition:

• Pre-development and design phase — 8 to 16 weeks for design development, structural engineering, civil engineering where needed, survey, arborist report, heritage pre-application consultation where applicable, and documentation.
• DSD plan-check — 6 to 14 weeks depending on project complexity and review completeness.
• Tree protection review — 4 to 8 weeks, often running in parallel with plan-check but capable of extending the critical path if significant protected-tree issues surface.
• Floodplain review — 6 to 12 weeks on floodplain parcels, often running in parallel.
• Heritage Landmark Commission review — variable; minor/administrative review 4-6 weeks, commission review 8-16 weeks depending on hearing schedules.
• Construction — 5 to 12 months for typical additions; second-story and major wrap-around projects trend toward the upper end.

Total window: 8 to 18 months from first design meeting to final inspection, with 10-12 months being typical for a straightforward rear addition on a non-heritage, non-floodplain parcel, and 14-18 months being typical for a major second-story or wrap-around in a heritage district.

What Baily verifies before any Austin addition match

Before routing an Austin home-addition lead to a contractor, Baily runs an institutional verification sequence. The project is only matched if every gate passes:

• TDLR credential check for electrical, HVAC, and any other regulated sub-trades on the contractor's roster.
• TSBPE plumbing check for the plumbing sub, verified against the Texas State Board of Plumbing Examiners roster².
• City of Austin contractor registration verification via DSD.
• Certificate of Insurance pulled directly from the carrier, current-dated, appropriate limits for project scope, naming the homeowner as additional insured on request.
• Workers' compensation or occupational accident coverage documented (Texas is a non-subscriber state but Baily requires coverage for match).
• DSD permit history — documented experience pulling and closing residential addition permits with DSD. A contractor with no Austin permit history is not matched to a major Austin addition regardless of out-of-area track record.
• Heritage district experience where applicable — for Hyde Park, Bouldin, Old West Austin, Old East Austin, and other heritage overlay projects, Baily checks for documented Landmark Commission work history.
• Floodplain experience where applicable — documented prior work on floodplain-permitted projects for any parcel with floodplain exposure.
• Tree protection track record — documented prior projects with protected or heritage trees on-site, with no enforcement actions or mitigation violations.

One lead, one contractor, one verified match. Not 12 strangers.

Frequently asked questions

Do I need a permit for my Austin home addition?

Yes, virtually any home addition in Austin requires a Development Services Department (DSD) permit. The permit triggers comprehensive review: structural compliance with Austin's adopted code (2018 IRC + amendments), zoning compliance (setbacks, FAR, lot coverage), tree protection review under Chapter 25-8 (any work near trees with 19" diameter at standard height triggers protection), drainage analysis (impervious cover changes for additions over 500 sqft), and floodplain review if your property is in the 100-year or 500-year floodplain. Submit via the BuildAustin or AB+C portal; expect 6-14 weeks for plan-check on a typical addition. Pre-development coordination meeting with DSD recommended before submission for additions over 500 sqft.

How does Austin's tree protection ordinance affect my addition design?

Chapter 25-8 protects any tree of a regulated species that measures 19 inches or larger in diameter at standard height (DSH, measured 4.5 feet above grade). Trees measuring 24 inches DSH or larger are heritage trees with more stringent protection. Each protected tree has a Critical Root Zone (CRZ) — roughly 0.5 foot of radius per inch of DSH — where no construction activity can occur without specific mitigation. A mature live oak can have a 20-30 foot-diameter protected area. Designing a rear addition into a CRZ without tunneling foundations, root-protective grade treatments, and arborist-supervised construction will either fail plan-check or require a variance. Get a certified arborist's site report before finalizing any addition design if mature trees are anywhere near the proposed envelope.

What if my property is in the Austin floodplain?

Floodplain parcels require a Floodplain Development Permit in addition to the building permit, elevation of any new finished floor to at least 1 foot above Base Flood Elevation (BFE), a surveyor-prepared Elevation Certificate, and compensatory storage if the addition reduces floodplain capacity. The substantial improvement rule is the hardest trap: if the cost of the addition plus any other recent improvements exceeds 50% of the pre-improvement market value of the structure, the entire structure may need to be brought into full floodplain compliance — which for an older low-elevation home can be prohibitive. Pull the floodplain determination from the City of Austin Floodplain Maps before committing to any design on a floodplain or floodplain-adjacent parcel.

How does a Hyde Park or Old West Austin heritage district affect my addition?

Heritage Conservation Districts and National Register Historic Districts apply additional review for exterior work on contributing structures. Minor rear additions not visible from the primary street may qualify for administrative/staff review (4-6 weeks), while larger additions, work on visible elevations, or additions to Historic Landmarks typically require Historic Landmark Commission review (8-16 weeks depending on hearing schedule). The core design principle is that additions must be subordinate to, compatible with, and differentiable from the original historic structure. Pre-application consultation with heritage staff before design development is the most effective way to avoid a multi-cycle review.

How does Baily verify my Austin contractor without a statewide GC license to check?

Texas does not issue a comprehensive state-level general contractor license, so "licensed in Texas" is not a single credential to verify. Baily runs a five-part verification stack: TDLR credentials for regulated sub-trades (electrical, HVAC, specialty), TSBPE for plumbing, City of Austin contractor registration via DSD, current Certificate of Insurance with appropriate general liability limits and workers' comp or equivalent coverage, and documented DSD permit closure history for residential additions. For heritage districts, we additionally verify Historic Landmark Commission project history. For floodplain parcels, we verify prior floodplain-permitted project work. One lead goes to one contractor that has passed every applicable gate for the specific parcel and project profile.

---

Footnotes

1. AskBaily, Austin HOME Initiative + ADU pillar, /austin/home-initiative-adu. Covers HOME amendments, detached ADU construction, garage conversion to ADU, and the broader Texas contractor-licensing context referenced throughout this pillar. ↩ ↩²

2. Texas Department of Licensing and Regulation, license verification portal: https://www.tdlr.texas.gov/LicenseSearch/. Covers electrical contractors, HVAC and refrigeration, and other regulated trades. Texas State Board of Plumbing Examiners — https://www.tsbpe.texas.gov — is the separate regulator for plumbing. ↩ ↩²

3. City of Austin Development Services Department — https://www.austintexas.gov/department/development-services-department. Primary permitting authority for residential construction within the City of Austin. AB+C (Austin Build + Connect) is the online permitting portal. ↩

4. City of Austin Watershed Protection Department, Floodplain Maps and Floodplain Development Permit requirements — https://www.austintexas.gov/department/floodplain-regulations. Coordinates with FEMA flood mapping for Special Flood Hazard Area determinations — https://msc.fema.gov/portal/home. ↩ ↩²

5. Austin Land Development Code, Chapter 25-2 (Zoning) — https://library.municode.com/tx/austin/codes/land_development_code. Defines base districts, overlays, setbacks, FAR, lot coverage, and compatibility standards. ↩

6. Austin Historic Landmark Commission, review processes for Historic Landmarks, National Register Districts, and local Historic Conservation Districts — https://www.austintexas.gov/department/historic-preservation-office. ↩

7. Austin City Code Chapter 25-8 (Environment), tree protection and critical root zone requirements — https://library.municode.com/tx/austin/codes/code_of_ordinances, administered by City Arborist and Development Services Department. ↩