By LE Construction · Updated October 2026
| Project | Figure | Source |
|---|---|---|
| Average construction cost per square foot (national, 2024) | $162 | NAHB Cost of Constructing a Home 2024 |
| Average construction cost, 2,647 sq ft home (national) | $428,215 | NAHB 2024 |
| Share of construction cost: interior finishes | 24.1% | NAHB 2024 |
| Share of construction cost: foundations / site work | 10.5% / 7.6% | NAHB 2024 |
The cost of building a house is usually quoted per square foot, and that number is only useful if you know what it includes. This guide starts with national construction data, explains what it covers, and walks through the Ventura County factors that move a custom home’s budget.
These figures come from the sources listed. Your budget comes from a review of your plans and your lot.
The national reference point
The National Association of Home Builders surveys builders each year on the cost of constructing a single-family home. In its 2024 survey, the average construction cost was $428,215 for a 2,647-square-foot home, or $162 per square foot, the highest in the survey’s history.
NAHB broke that construction cost down this way:
| Category | Share of construction cost |
|---|---|
| Interior finishes | 24.1% |
| Major system rough-ins (plumbing, electrical, HVAC) | 19.2% |
| Framing | 16.6% |
| Exterior finishes | 13.4% |
| Foundations | 10.5% |
| Site work | 7.6% |
| Final steps | 6.5% |
| Other | 2.1% |
Two things to keep in mind: the figure excludes land, and it reflects homes built by production builders across the country, not custom homes.
Why custom homes here cost more
Design and finishes
Custom homes have more complex rooflines, larger windows, higher ceilings and better finishes than a typical production house. Since interior finishes are already the largest share of construction cost, finish choices move a custom budget more than anything else.
Site work on real lots
Hillside lots around Ojai, Camarillo and the Conejo Valley need stepped footings, retaining walls and drainage. Rural lots around Somis and Piru need septic systems, wells or water service, and long driveways that meet fire department access rules.
Code requirements
New homes in California require automatic fire sprinklers. In mapped fire hazard zones, Chapter 7A sets standards for roofing, vents, siding, eaves, windows and decks. Current energy code requirements apply as well.
Approvals
Plan check, Environmental Health review for septic and wells, fire department review and, in some places, design or coastal review all take time and fees.
Keeping a custom home on budget
- Have a builder price preliminary plans before they are final.
- Keep the roofline and footprint simpler where it does not hurt the design.
- Set realistic allowances for finishes and make selections early.
- Budget for the site, not only the house.
See our custom homes, custom home building and fire rebuilds pages.
Sources
- National Association of Home Builders, Cost of Constructing a Home 2024
- Ventura County Mountain Fire permit fee waivers (KCLU, Dec 2024)
Published figures are national or regional averages from the sources above and are not LE Construction quotes. Prices change; your written estimate is the number that counts.
Frequently asked questions
Does the NAHB figure include the land?
No. The $162 per square foot figure is construction cost only. In the NAHB survey, finished lot cost was a separate share of the sales price, and the survey covers production builders rather than custom homes, which usually cost more per square foot.
Why would a custom home in Ventura County cost more than the national average?
Custom design and finishes, higher regional labor and material costs, and site conditions all push it up. Hillside lots need engineered foundations, rural lots need septic and wells, and homes in fire hazard zones must meet Chapter 7A standards. New homes in California also require fire sprinklers.
What is the biggest single category in building a house?
In NAHB's 2024 breakdown, interior finishes were the largest share of construction cost at 24.1%, followed by major system rough-ins such as plumbing, electrical and HVAC at 19.2% and framing at 16.6%. Finish selections are where custom budgets most often grow.
Are there savings for rebuilding after the Mountain Fire?
The County of Ventura approved permit fee waivers for Mountain Fire rebuilds, estimated at about $20,000 per dwelling, in effect through December 31, 2026 with possible extensions. Construction costs themselves are not waived. Check with the County for current status.