Interior finishes: the biggest stage of a new house, item by item

The stage, line by line

The share of construction cost going to interior finishes has fallen over the past decade, from 29.3% in the 2013 survey to 24.0% in 2022 and 24.1% in 2024, as costs for systems and other stages rose.[1] In dollars, though, it is still the biggest single stage, and the one most under your control.

Behind the walls: insulation and drywall

Insulation ($6,992 on average) is one of the few finishes you cannot easily improve later. Code sets the minimum by climate zone, but going beyond it, or adding air sealing and insulated ducts, can reduce the size of your HVAC system and your energy bills for decades. Ask your builder exactly what insulation goes in the walls, attic, floors over unconditioned space and rim joists, and how air sealing is checked.

Drywall ($13,962) is priced mostly by wall and ceiling area. Tall ceilings, vaulted rooms, curves and many corners add labor. The level of finish matters too: smooth walls for glossy paint or strong side light need more finishing work than a light texture. Moisture-resistant board in bathrooms and fire-rated board between the garage and the house are often required by code.

Trim, doors and paint

Interior trim, doors and mirrors averaged $12,920. Door style is a big lever: solid-core doors feel and sound better than hollow-core but cost more, and each door adds hardware. Trim profiles, crown molding, wainscoting and built-in shelving add both material and finish carpentry time. A simple, consistent trim style throughout the house costs less than varied details in each room.

Painting averaged $11,150. The price depends on surface area, the number of colors, the paint grade and how much trim and how many doors are painted on site. Each extra wall color adds cutting-in time; dark colors may need more coats. Accent walls are cheap to add later, so a calm base palette at build time is an easy saving.

Flooring, fixtures and lighting

Flooring averaged $15,388. It is priced by area and material, plus installation and subfloor preparation. Tile costs more to install than most other floors; site-finished hardwood costs more than prefinished; luxury vinyl plank and carpet are usually at the lower end. Many owners use a durable, mid-priced floor in the busiest rooms and save on bedrooms, where carpet or a lower-cost plank is fine.

Plumbing fixtures averaged $7,922 for the whole house: sinks, faucets, toilets, tubs, showers and their trim. The number of bathrooms drives this line more than anything. Custom tile showers with glass enclosures cost much more than one-piece units.

Lighting averaged $5,392. Recessed lights, pendants and under-cabinet lights each add fixtures and electrician time. Plan the lighting with the electrician before rough-in, because moving a fixture after drywall means patching and repainting.

The fireplace line averaged $2,378, or 0.6% of construction cost. That figure is a national average, so it says little about what one fireplace in your house will cost. A fireplace adds the unit, venting or chimney, a surround and often gas piping, so if you want one, price it as its own item rather than relying on the national average.

Kitchen items, cabinets, counters and appliances, are covered in detail in our guide to kitchen costs in a new build.

The order finish work happens in

Finishes follow a fairly fixed sequence, and knowing it helps you time your selections. After the rough-in inspections pass, insulation goes in and is inspected. Drywall is hung, taped and finished, which takes several visits while each coat dries. Then come primer and often the first coat of paint, followed by interior doors and trim, cabinets, and countertops, which are templated only after the cabinets are set.

Flooring goes in around this point; the exact order depends on the material and the builder, since some floors are protected under trim while others go in after it. Tile, plumbing fixtures, light fixtures and appliances come next, then final paint touch-ups, hardware, mirrors and shelving, and finally cleaning and the punch list.

Each trade depends on the one before it. A late flooring delivery or a light fixture on back-order can hold up the final inspection and your move-in date, so confirm lead times when you make each selection and order long-lead items early. Our guide to how long it takes to build a house shows where finishes sit in the full timeline.

Allowances and selections: where finish budgets slip

Most builders handle finishes with allowances: a set amount for flooring, lighting, fixtures and so on. You pick the products, and if they cost more than the allowance you pay the difference, usually with the builder's markup. Allowances that are set low make a bid look cheap and push costs to later.

To keep control:

• Visit the builder's suppliers before you sign and price what you actually like.
• Check whether each allowance includes installation, or only materials.
• Make as many selections as possible before the contract, so they become fixed items.
• Keep a running total of allowance overages next to your contingency, and review it every month.
• Ask for samples of the standard finishes so you know what the base allowance actually looks like.
• Respect the selection deadlines; late choices delay the schedule and cost change-order fees.

See change orders and cost overruns for a simple way to track this.

Where to spend and where to save

A useful rule: spend on things that are expensive or disruptive to change later, and save on things you can swap out once you have lived in the house for a while.

Worth spending on during construction: insulation and air sealing; waterproofing behind showers and tile; solid subfloors; blocking in walls for future grab bars, shelves and TVs; enough outlets and circuits; good ventilation in bathrooms and the kitchen; and durable flooring in entries and kitchens.

Easy to upgrade later: light fixtures, cabinet hardware, faucets, mirrors, paint colors, closet systems, window coverings and secondary-room flooring.

Simplifying the design helps too. Fewer interior corners, a consistent trim style, standard door sizes and stacking bathrooms above each other all reduce labor across several lines of this stage. Our guide to the cheapest ways to build a house has more ideas.

Using the calculator for finishes

The calculator breaks Interior Finishes into the same eleven lines as the NAHB survey. Start with the national averages, then replace each line with your allowance or quote as you get them. If you are planning premium finishes throughout, your interior share may end up well above 24.1%; if you are keeping finishes simple, it may come in below. Either way, compare the stage total with the rest of your budget to see whether finishes are where the money is going.

Because finishes come last, they are also where budgets get squeezed if earlier stages run over. Protect them by keeping a separate contingency for surprises in site work and foundations, so your finish choices are not made under pressure at the end of the job.

Frequently asked questions

Sources

1. NAHB: Cost of Constructing a Home 2024 Verified

Figures last checked October 18, 2026. National averages are a planning guide, not a quote. See our editorial policy and data sources.