What happens during the design phase of building a custom home?

The design phase is where your ideas become a buildable set of plans. You and your design team develop the floor plan and elevations. You make your finish selections, like cabinets, tile, fixtures, and flooring. Then a structural engineer produces a stamped plan set that meets the building and energy codes. In Arizona this set almost always includes a structural design and energy calculations. It often includes a geotechnical soils report too, because problem soils are common here and drive the foundation design. This phase usually runs 2 to 5 months. It decides most of your home's cost, look, and how smoothly the rest of the build goes. Getting it right is what lets your builder pull a permit without delay.

From concept to a permit-ready plan set

The design phase moves from rough concept to a complete, stamped plan set in a few clear stages. Each stage adds detail until the drawings are ready for a city or county reviewer.

It usually starts with schematic design: rough floor plans and the general look, sized to your lot, your budget, and the setbacks your zoning allows. Next comes design development, where rooms, ceiling heights, window placement, and major systems get fixed. Then construction documents: the detailed, dimensioned drawings the crew will actually build from and the city will review.

By the end, your plan set includes the site plan, floor plans, elevations, structural plans, and the supporting documents the jurisdiction requires. Scottsdale's submittal guidelines for single-family homes spell out exactly what a complete package contains, and an incomplete set is the most common reason a first review comes back with corrections. A clean, complete submittal is the fastest path through plan review, which Scottsdale targets at about 22 business days for a new-construction first pass.

The people involved usually include a designer or architect who shapes the home, a structural engineer who makes it stand up and provides the stamp, and your builder, who keeps the design buildable and on budget. Bringing the builder into design early prevents drawing something beautiful that costs far more than your budget allows.

The Arizona engineering that has to happen in design

In Arizona, the design phase carries engineering work that the desert climate and soils make non-negotiable. Three pieces matter most: the soils report, the foundation design, and the energy calculations.

The soils report, also called a geotechnical report, comes first because it drives the foundation. The Arizona Geological Survey warns that problem soils are found throughout the state and that expansive soils cause "foundation cracks" and "heaving and cracking of floor slabs and walls." It recommends hiring a geotechnical firm to "take soil borings" and "test the expansiveness of the soil" before building. That report tells the engineer whether a standard slab works or whether your home needs a post-tension or otherwise engineered foundation.

The foundation design follows from the soils. Scottsdale's residential guidelines set a footing depth minimum of 18 inches below grade, or deeper per the soils report, and require engineered calculations and the geotechnical report for alternate methods like post-tension. Designing this correctly during the design phase is far cheaper than discovering a soil problem during construction.

The energy calculations prove the home meets the adopted energy code. That code is based on the International Energy Conservation Code (IECC). For Arizona's hot climate, the code sets minimum insulation R-values, window U-factors, and air-leakage limits. Your plans must show all of them. These choices, made on paper now, are what keep your cooling bills low later. So the design phase is the right time to decide on insulation, window specs, and HVAC sizing.

The decisions you make, and why making them now matters

The design phase is where you make the choices that lock in your home's cost and timeline, and front-loading them is the single biggest favor you can do your project. Every decision left open becomes a change order later.

You choose the layout, the room sizes, the ceiling heights, and the flow. You choose the exterior look and materials. And you choose the finishes: cabinets, countertops, tile, flooring, plumbing fixtures, lighting, and appliances. These selections feel endless, but making them during design, while they are still lines on a page, costs nothing to change. Making them during construction means a crew waiting, materials reordered, and the schedule slipping.

Long-lead items deserve special attention here. Custom windows, certain appliances, and specialty materials can take weeks or months to arrive, so choosing them during design lets your builder order them early and avoid a gap mid-build. A selection made in month two of design is a non-event. The same selection made during framing can stall the job.

Two more design choices are worth getting right now because Arizona makes them matter. Orientation and shading affect how hard your home works to stay cool, so window placement and roof overhangs designed for the sun pay off every summer. And lot-specific drainage matters because the monsoon (June 15 to September 30) drops heavy rain fast, so grading and drainage are designed in, not added later. We sit with you through these decisions, keep the engineering and the budget aligned, and hand off a complete plan set, so plan review and construction both run without avoidable delay.

How design ties to your budget and timeline

The design phase is also where your budget gets real, because the plans set the price. A wider footprint, higher ceilings, more glass, and richer finishes all add cost. The point of design is to find the version of your home that fits both your wishes and your number, before any money goes into the ground.

A good builder prices the design as it develops, not just at the end. That way, if a choice pushes you over budget, you see it while it is still a line on a page. Adjusting a drawing is free. Tearing out a framed wall is not. This is why bringing your builder into design early saves more money than almost anything else you can do.

Design also sets your timeline. The plan set has to be complete before your builder can submit for a permit. A thin or sloppy set comes back from plan review with corrections, and each correction round adds weeks. A complete set clears review faster. So the time you spend getting design right is not lost time. It is time you take out of the back end of the project.

Treat the design phase as the slow, careful part of the build. Make your decisions here, lock them, and let construction be fast. Owners who do this get the custom home they wanted, on a schedule that holds. The reverse is also true. Owners who rush design and keep changing their minds during construction pay for it in both dollars and weeks. The design phase is short compared to the years you will live in the home, so it is worth the patience. Spend it well, and you carry a clear plan into construction, where every dollar and every week then works in your favor. A finished design is the most valuable thing you can hand a builder, because it removes the guesswork that causes most delays and cost overruns.

Building with Jematell Homes

We are a licensed, family-owned Arizona custom home builder. Every project is different, so we will confirm the specifics for your parcel and budget with you directly.

Sources

• Arizona Geological Survey: Problem Soils (expansive and collapsing soils)
• City of Scottsdale: Single-Family Residential Quality Submittal Guidelines
• ICC: 2018 IECC, Chapter 4 Residential Energy Efficiency
• City of Scottsdale: Plan Review Services (review timeframes)
• City of Scottsdale: Building Code Information (adopted codes)