September 2026 RoMac Whole House Commodity Report: A Flat Index Hides Real Volatility

RoMac Whole House Commodity Index, September 2026: $54,321. The Index tracks wholesale costs for a 2,200-square-foot wood-frame home with a concrete stem wall in Central Florida.

The RoMac Building Supply Whole House Commodity Index for September 2026 came

in at $54,321, essentially unchanged from $54,323 in August. Don't read that as a quiet

month. OSB surged more than 10 percent, Southern Pine 2x4s jumped nearly 16

percent, 2x12 Southern Pine dropped nearly 11 percent, and spruce studs fell 4.8

percent. The gains and losses largely canceled each other out, which is why the Index

barely moved.

A flat Index doesn't mean flat costs. Labor, fuel, financing, land, and insurance all sit

outside this Index, and several of them are moving in the wrong direction. The full

picture heading into fall is more complicated than one number can show.

New-Home Market Weakens Further

The national new-home market took a hard step back in July. New single-family home

sales fell 10.5 percent from June to a seasonally adjusted annual rate of 607,000 units,

the sharpest monthly drop and the lowest level since January. Sales were also 6.3

percent below July 2025, coming in well below the market forecast of 620,000.

Inventory tells the fuller story. There were 488,000 new homes available for sale at the

end of July, which works out to 9.6 months of supply at the current sales pace. A

balanced market is four to six months. The median new home price dropped to

$393,800, its lowest level since July 2021, and it's now down about 14 percent from the

peak. Most of that is a shift in the mix of homes being sold, but builder discounting is

also real.

Single-family starts dropped 9.9 percent in July to 808,000 annualized, the third decline

in four months. Total starts fell 12.4 percent to 1.239 million, the second-lowest reading

since the pandemic. One counterpoint: single-family permits rose 2.5 percent in July to

894,000, which tells you builders haven't abandoned future projects even as they're

pulling back on current ones. The gap between permits and actual starts says a lot

about how cautious the industry is right now.

Builder sentiment fell three points to 32 in September per NAHB, well below the 50

threshold that separates expansion from contraction. In September, 38 percent of

builders cut home prices, and 66 percent used sales incentives. NAHB Chairman Bill

Owens noted that rising gas and diesel prices are pushing up material costs and that

spec building remains weak as buyers stay on the sidelines. The Midwest was the one

bright spot, with new home sales up more than 2 percent year-to-date in that region.

Builders Are Getting Squeezed From Both Sides

The real problem isn't just slower sales. It's the math of building homes when buyers

can't afford higher prices and construction costs aren't coming down enough to close

the gap.

NAHB survey data shows builders reported a median 6.7 percent increase in material

costs over the past year. Smaller builders are absorbing more of it. Those producing five

or fewer homes reported a 9.1 percent increase, compared to just 1.8 percent for

builders producing 100 or more. Scale matters on supply contracts, and the smaller

guys are feeling it directly.

Labor is another layer of pressure that doesn't show up in the Index. Skilled trades are

hard to find and expensive. Shortages extend schedules, reduce how many homes you

can complete, push up subcontractor pricing, and make every delay more costly when

you're carrying financing at today's rates. These things are eating into margins on every

job.

Fuel is back as a real cost driver too. National gasoline prices rose 3.9 percent in

August alone, and overall energy prices were up 16.3 percent year-over-year. Higher

diesel runs through freight charges, vendor pricing, and manufacturing costs.

Petroleum-dependent products carry additional raw material pressure on top of that. A

flat Index doesn't tell that story.

Rates Are Higher and Still Not the Whole Story

Florida's August numbers tell a more nuanced story than earlier in the year. The

momentum that built through 2025 and the first half of 2026 has slowed.

Florida Realtors reported 21,497 closed single-family sales in August, down 1.4 percent

year-over-year. Condo and townhouse sales fell 1.8 percent to 7,291. The statewide

median single-family price was $415,000, up 1.2 percent from a year ago. Single-family

inventory tightened to 4.3 months of supply. Condo and townhouse inventory remained

elevated, giving buyers in that segment real negotiating leverage.

Florida Realtors Chief Economist Dr. Brad O'Connor put it plainly: August ended several

growth streaks that had been running for most of the past year. Coming into August,

Florida had seen 12 consecutive months of year-over-year increases in new pending

sales for single-family homes and 11 straight months of rising closed sales. Both ended

in August. Rates are the story. We're now above where we were a year ago, and that

was enough to break the streak.

The market is leveling off, not collapsing. Prices are holding. Single-family inventory is

tightening. But if you were counting on that year-over-year momentum to continue, it's

time to recalibrate.

One thing worth pointing out: new construction is now cheaper than resale in a way it hasn't been in decades. NAHB data shows the national median price for a new single-

family home in Q2 2026 was $410,700, which was $25,000 below the existing home median of $435,700. That's the largest gap on record in favor of new construction. In

July it widened further, with new homes at $393,800 against a resale median of

$434,100. This price inversion has held for four consecutive months, the longest stretch

on record. The traditional new home premium historically averaged about 16 percent

above resale. That premium is now negative. Some of it reflects smaller homes and

more incentives, but the competitive position of new construction has shifted in a real way. Buyers who have been assuming new construction is out of reach should hear

otherwise.

Mortgage Rates Are Moving Higher, Not Lower

Rates have moved in the wrong direction heading into fall. The 30-year fixed averaged

6.71 percent the week of September 3rd per Freddie Mac and climbed to 6.76 percent

the week of September 10th. A year ago, the rate was at 6.35 percent. Buyers are

paying more to borrow than they were a year ago, reversing the trend that had

supported Florida's sales through much of 2026.

It's less about whether people want homes now and more about whether the payment

works. Wage growth has helped at the margin, and builders are offering buydowns and

incentives to close the gap. But with rates higher year-over-year and prices not dropping

significantly, the math is harder than it was six months ago. Plan around upper-6

percent rates for the rest of 2026. Waiting for a big rate drop before making decisions

isn't a strategy the data supports.

Major Commodity Price Movers: Last 30 Days

September is exactly why you can't just watch the headline Index number. The overall

Index barely moved, but individual categories moved aggressively.

On the upside: OSB sheathing rose 10.7 percent, taking back most of August's decline.

Southern Pine 2x4 jumped 15.7 percent and borate-treated Southern Pine increased

10.7 percent. Interior millwork also moved higher, with colonial casing up 5.6 percent,

base moulding up 5.1 percent, and standard interior door units up about 3.6 percent.

On the downside: Southern Pine 2x12 dropped 10.9 percent. Spruce studs declined 4.8

percent, 2x4 spruce fell 1.8 percent, 2x6 spruce fell 1.7 percent. Southern Pine 2x6 was

flat.

Outside of structural lumber, most categories were quiet. Roofing, drywall, insulation,

siding, and windows showed little movement during the month.

Bottom line: if you were buying OSB and 2x4 Southern Pine in September, you saw real

inflation. If you were buying 2x12 Pine or spruce studs, you saw real savings. Managing

by product category is more important right now than watching the Index.

Outlook and Guidance for Builders

Don't price jobs off the direction of the Index. September is the clearest example we've

had this year of why that fails. The total house package was flat while individual

structural products moved more than 10 percent in either direction. Know your exposure

by product, not just the aggregate.

Lock in favorable pricing when you see it. The swings in Southern Pine and OSB this

fall show clearly that today's price isn't guaranteed next month. If a product you need

has pulled back, get a firm quote and take it.

Pay attention to freight and delivery costs. Fuel is a real expense again, and every

partial load, unnecessary delivery, or avoidable site trip costs more than it did six

months ago. Tighten up scheduling and staging.

Give labor efficiency the same attention. When skilled workers are hard to replace,

mistakes, rework, bad material orders, and schedule slippage all cost more than they

used to. Getting it right the first time matters more right now.

Keep escalation clauses in contracts on longer projects. Volatility hasn't gone away, it's

just more concentrated within categories than across the full Index. That makes

surprises harder to see coming. Protect yourself contractually.

Watch Florida but with realistic expectations. The 12-month run of improving sales has

ended. The underlying fundamentals here are still better than the national numbers

suggest, single-family inventory is tightening, and buyers are still in the market. Builders

who stay disciplined on pricing, manage costs by category, and control execution are

still well-positioned in Central Florida.

The RoMac Building Supply Whole House Commodity Index is based on wholesale costs of the base components to build a 2,200-square-foot wood-frame home with a concrete stem wall in Central Florida. The Index includes foundation, metal, concrete, block, stucco, cement, wood framing, siding, sheathing, trusses, roofing, drywall, insulation, windows, doors, trim, garage doors, and most building hardware. It does not include decor, electrical, plumbing, mechanical, landscaping, or labor. Because the Index uses current wholesale costs, it serves as a leading indicator of the direction of residential building material prices over the next 30 to 45 days.

Jake Trapp is the President of RoMac Building Supply in Central Florida.

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