What to Expect: The Custom Home Building Timeline in Hillsborough

Why Hillsborough Has Its Own Timeline

If you have built or remodeled in other Bay Area cities, set those expectations aside. Hillsborough operates differently, and the timeline for building a custom home here reflects the town’s unique character and priorities.

Hillsborough is one of the few municipalities in California zoned entirely for residential use. There are no commercial properties, no retail, no offices. The town was incorporated in 1910 specifically to preserve its residential character, and that commitment shapes every aspect of the building process today. Minimum lot sizes start at half an acre, the minimum home size is 2,500 square feet, and large estates on winding, tree-lined roads define the landscape.

The most significant difference for homeowners planning new construction is the Architecture and Design Review Board (ADRB). Every new home in Hillsborough must go through this design review process before a building permit can be issued. The ADRB evaluates neighborhood compatibility, architectural quality, materials, landscaping, and privacy impacts. It is a thorough process, and it adds time that you will not encounter in most other Peninsula cities.

Combined with restricted construction hours, tree preservation requirements, and the estate-scale scope of most projects, Hillsborough timelines run longer than what you might expect from experience elsewhere. The total journey from design kickoff to move-in typically takes 18 to 30 months.

For an overview of the general custom home building process, see our custom home building process guide.

Phase 1: Pre-Design and Feasibility (1 to 3 Months)

Before any design work begins, you need a clear picture of what your lot allows and what constraints you are working within.

Site evaluation. Most Hillsborough custom home projects are teardown-rebuilds on lots with existing homes. A thorough site evaluation covers topography, soil conditions, drainage patterns, existing tree locations, utility access, and any easements. For hillside lots, a geotechnical survey is essential early because it directly affects foundation design, grading scope, and construction cost.

Zoning review. Hillsborough has multiple residential zones, each with different setbacks, coverage limits, floor area ratios, and height restrictions. Height is measured from natural grade, which significantly constrains the building envelope on sloped lots. Your design-build team should pull the specific development standards for your parcel before beginning schematic design.

Budget framework. Construction costs in Hillsborough range from $500 to $1,000+ per square foot. Hillside conditions, premium finish levels, and the scope of site work (driveways, motor courts, landscaping, pools, guest houses) all influence where your project falls in that range. Establishing a realistic budget framework during feasibility prevents costly redesigns later.

Initial consultation. The Town of Hillsborough encourages early conversations with the Building and Planning Department. Their staff can clarify zoning questions, explain the ADRB process, and flag any site-specific issues before you invest in full design.

Phase 2: Design and ADRB Review (3 to 8 Months)

This is where Hillsborough’s process diverges most from other Bay Area cities. The Architecture and Design Review Board adds a layer of review that does not exist in many neighboring jurisdictions.

How the ADRB Works

The ADRB is a five-member volunteer board appointed by the City Council. Members typically have backgrounds in design, architecture, or construction. The board meets at 4:00 p.m. on a scheduled calendar, roughly once per month, with approximately 11 meetings per year. The schedule is not evenly spaced, so checking the annual ADRB calendar is essential for planning your submissions.

The Two-Step Review for New Homes

All new home applications must receive a preliminary review by the ADRB before a formal application can be submitted. The preliminary review is your first opportunity to present the project concept and hear feedback on massing, scale, style, and neighborhood compatibility.

After preliminary review, you refine the design based on board feedback and submit a formal ADRB application. A pre-application meeting with a Planner is required before submission, and a half-hour consultation is included in the ADRB application fee.

What the ADRB Evaluates

The board reviews your project against several criteria:

• Neighborhood compatibility. Does the design respect the scale, character, and quality of surrounding homes?
• Massing and proportions. Is the home proportional to the lot?
• Material quality. Hillsborough expects premium exterior materials.
• Privacy. Window placement, balcony orientation, and outdoor living areas are evaluated for their impact on neighboring properties.
• Landscaping. The landscape plan must integrate with Hillsborough’s mature tree canopy and natural setting.
• Site work. Driveways, motor courts, grading, and drainage are all part of the review.

Neighbor Outreach

The ADRB strongly encourages applicants to discuss the project with surrounding neighbors early in the design process. The Town recommends outreach to all neighbors within a 500-foot radius. Projects that arrive at the ADRB with unresolved neighbor objections face a harder path.

Typical ADRB Timeline

Most new custom home projects require 2 to 4 ADRB meetings before final approval. Given the board’s roughly monthly meeting schedule, this means 2 to 5 months for the review process alone.

Phase 3: Permitting (2 to 3 Months)

Once the ADRB grants approval, you can submit for a building permit. Initial plan review for major projects takes 4 to 5 weeks according to the Town. However, new custom homes with their full scope of documentation typically require 6 to 12 weeks for complete plan review, including any correction cycles.

Correction cycles. Plan check comments are common, and each round of corrections and resubmission adds 2 to 4 weeks. A thorough, code-compliant first submission minimizes these cycles.

Overlap with ADRB. Smart teams advance engineering and construction documents while the ADRB process is still underway. This means you are ready to submit for permits shortly after receiving ADRB approval rather than starting from scratch. That overlap can save 4 to 8 weeks.

For broader context on Bay Area permitting, see our guide to building permit timelines across the Bay Area.

Phase 4: Construction (12 to 18 Months)

With permits in hand, construction begins. The duration depends on scope, site conditions, and complexity.

Site preparation and demolition (2 to 4 weeks). Tree protection measures must be installed before any site work begins.

Foundation (4 to 8 weeks). Hillside lots may require engineered retaining walls, caissons, or pier foundations that extend this phase significantly.

Framing (6 to 10 weeks). Hillsborough homes are large. A 5,000 to 8,000 square foot home with complex roof lines takes longer to frame than a compact floor plan.

Mechanical rough-in (4 to 6 weeks). Electrical, plumbing, HVAC, and low-voltage systems installed before walls are closed.

Exterior finishes (4 to 8 weeks). Given the ADRB’s review of material quality, exterior finishes tend to involve premium materials with longer lead times.

Interior finishes (8 to 14 weeks). Drywall, paint, cabinetry, countertops, flooring, fixtures, and trim. Custom millwork and imported materials extend this phase.

Final inspections and punch list (2 to 4 weeks). The Building Department conducts final inspections before issuing a certificate of occupancy.

Landscaping (4 to 8 weeks, often concurrent). Given Hillsborough’s emphasis on landscape integration, this is a significant scope item.

Construction Hour Restrictions

Hillsborough limits construction activity more strictly than most Peninsula cities:

• Monday through Friday: 8:00 a.m. to 5:00 p.m.
• Saturday: 10:00 a.m. to 5:00 p.m.
• Sunday and Town holidays: No work permitted

Shorter working days are a meaningful factor in overall construction duration. A project that might take 10 months in a city with 7:00 a.m. to 6:00 p.m. hours will take longer here.

Common Timeline Additions

Hillside Grading

Properties on Hillsborough’s western slopes often require extensive grading, engineered retaining walls, and specialized drainage systems. This can extend the foundation phase by 4 to 8 weeks or more.

Tree Preservation

Hillsborough’s tree protection ordinance designates any tree with a trunk diameter of 18 inches or greater (measured at 4 feet, 6 inches above grade) as a protected tree. Removing a protected tree requires both design review approval and a tree removal permit. The penalties for violations are significant.

Design Revisions After ADRB Feedback

If the ADRB requests substantial changes, your design team needs time to revise and resubmit. Each revision cycle consumes the time between board meetings, which can be 4 to 6 weeks. Two rounds of significant revisions can add 2 to 4 months.

How to Plan Realistically

Understand the ADRB Calendar

Check the current year’s meeting calendar and plan your design milestones around it. Missing a submission deadline means waiting until the next meeting.

Start Design Early

Begin schematic design as soon as your lot is under contract. The pre-design feasibility work, site surveys, and geotechnical studies can start immediately.

Build Contingency Into Every Phase

• ADRB review: Plan for 4 to 5 months even if you hope for 2 to 3
• Permitting: Plan for 10 to 12 weeks including corrections
• Construction: Add 10 to 15% schedule contingency

Work With a Team Experienced in Hillsborough

The ADRB’s expectations and the Town’s construction requirements are specific to this community. A design-build team that has worked in Hillsborough understands what the board looks for, how to structure submissions, and how to run construction within the Town’s rules.

Experience translates directly into fewer revision cycles, cleaner permit submissions, and a construction process that respects the Town’s requirements from day one.

Ready to discuss your Hillsborough project? Get in touch with our team to start with a feasibility conversation and realistic timeline tailored to your property.