The short answer. There is no single number, because each project is different. A custom home goes through three phases: design, permitting, and construction, and this article gives an estimate for each. Design has three stages, estimated at 4-6 weeks, 4-6 weeks, and 6-8 weeks. A building permit is estimated at 2-4 months, and a site plan review, where one applies, at 1-2 months. New construction typically takes 12-18 months. Design depends on how quickly decisions are made. Permitting depends on the jurisdiction. Construction depends on the house, the site, the builder, and the weather.
What happens before design starts?
Before anyone draws the house, a few things need to be in place: the land (or a short list of lots), a rough budget, a sense of what the house needs to do, and ideally a survey. If you are still choosing a lot, some of the design thinking happens here, as the architect helps you understand what each property allows.
This stage can be short or long. It is usually shortest for owners who arrive with a lot, a budget, and clear priorities.
It is also the right time to gather the documents the design will rely on: the survey, any soil or septic information, the deed restrictions or HOA covenants, and the utility information for the lot. Having them early prevents the design from being redrawn when a constraint turns up later.
How long does design take?
Design is usually divided into stages, each ending with decisions you approve before the next begins:
- Schematic design. The first plans and the overall form of the house, and how it sits on the lot.
- Design development. Materials, windows, structure, and systems are decided, and the drawings become precise enough for a builder to give a reliable price.
- Construction documents. The detailed drawings and specifications the builder builds from and the building department reviews.
The biggest factor in how long design takes is the pace of decisions. A design that changes direction late costs time, because the drawings that follow have to be redone. Engineering, surveys, and any HOA review also run during this phase.
Each project is unique depending on scope of work and project size, so the estimates can vary:
Schematic Design: 4-6 weeks meeting on a weekly and bi-weekly basis
Design Development: 4-6 weeks meeting on a weekly and bi-weekly basis
Construction Documents: 6-8 weeks meeting bi-weekly.
How long does permitting take?
Once the drawings are complete, they go to the building department that has jurisdiction over your lot: the City of Brentwood, the City of Franklin, unincorporated Williamson County, or another city or town. The department reviews the drawings and may return comments, which the architect answers before the permit is issued. If the lot uses septic, the county's septic approval is part of this picture. If the property is in Franklin's historic overlay, a Certificate of Appropriateness is needed before work starts.
Review times depend on the department, the season, and how complete the submittal is. A well-coordinated set of drawings usually needs fewer rounds of comments.
1-2 months for a site plan review and approval (if applicable)
2-4 months for a building permit
Building permits in Brentwood, Franklin, and Williamson County
How long does construction take?
Construction is usually the longest phase. Its length depends on:
- Size and complexity. More square footage, custom millwork, stone, and complex roofs take longer.
- The site. Slopes, rock, long driveways, and septic work add time before the house itself goes up.
- The builder's schedule and crews. A good builder in a busy market may have a waiting list.
- Materials. Custom windows, specialty finishes, and some equipment have long lead times, which is why they are often ordered well before they are needed.
- Weather. Rain affects site work and foundations, and winter can slow some trades.
Construction schedules can vary greatly depending on the size and scope of the project. Typically remodels and additions can take 4-8 months to complete and new construction 12-18 months.
What usually causes delays?
- Late decisions and changes. A change after construction starts can ripple through the schedule and the budget.
- Incomplete drawings. Questions the drawings do not answer have to be answered on site, and that takes time.
- Permit resubmittals. Each round of comments adds time.
- Long-lead items ordered late. Windows, doors, and specialty items that are not ordered early can hold up the work.
- Site surprises. Rock, water, or poor soil found after digging starts.
Most of these can be reduced before construction begins: settle decisions during design, complete the drawings, check the site early, and order long-lead items on time.
What helps a project move faster?
- Buy the land with the site checks done first.
- Set a realistic budget early, so the design does not have to be cut back later.
- Make decisions during design, not during construction.
- Choose the builder early enough to price the design as it develops.
- Keep the same architect involved through construction, so questions on site are answered by someone who knows why each decision was made.
Does the time of year matter?
It can. Starting site work and foundations in a dry season is easier than in a wet one, so some owners plan design to finish in time for site work to begin when the weather is favorable. Builders' schedules also fill at certain times of year. It is worth talking about timing with your architect and builder early, so the drawings are ready when the builder and the weather are.
What happens at the end of construction?
When the house is nearly complete, the architect and builder walk through it and list what still needs to be finished or corrected, often called a punch list. The building department does its final inspection and issues a certificate of occupancy, which allows the house to be lived in. Many builders also provide a warranty period after move-in. Leave time for this last stretch in your planning, especially if you are selling another home or moving from out of state.
I prefer to walk with the client, general contractor and the interior designer at various stages of the construction phase to review the progress and where any potential issues or concerns can be addressed. Also, it is critical near the end of the project to walk with the team and develop a punch list with responsibilities.
Can you design from out of state?
Yes. Owners who still live in another state can design and build a house here. Most design meetings can happen by video, with site visits planned around key decisions. What matters most is having someone local who represents you on site.
I have worked with many clients who are not local or the project is not local for my firm so we will meet virtually once a week in the beginning and as needed as the project proceeds in design. I will share my screen and walk through the drawing and the 3d model with follow up email correspondence with the client and contractor for a seamless project flow.
About the author
Paul Packman, NCARB, is President of Packman Architects in Brentwood, Tennessee. He is licensed in Tennessee, California, Oregon, and Utah.
From the first conversation through design, permitting, consultant coordination, and construction, he remains closely involved, helping clients navigate complex decisions while keeping their vision, priorities, and budget at the center of the project.
