Edition 1: September 2026

This is the first edition. It covers producer prices through August 2026 for six construction-material groups, with five years of history behind each. Later editions report what changed against it. It is written for anyone revisiting the material assumptions behind an estimate or weighing an explanation for a proposed increase. It reports market evidence. It does not estimate any contractor's cost and draws no conclusion about any contract.

The read

The metals rose; the mineral products did not. Copper wire and cable, steel mill products and aluminum mill shapes are each more than 20% above August 2025 in the producer price index: copper wire and cable +27.2%, aluminum mill shapes +27.3%, steel mill products +23.4%. Gypsum products (+0.2%) and ready-mix concrete (+2.3%) are close to flat over the same year, and the cement index behind concrete is slightly lower (−1.2%). Softwood lumber sits between the two groups at +11.8%, and most of that rise came this year: the lumber index is 17.9% above last December.

An explanation that says "materials are up 25%" therefore fits the metals and does not fit gypsum, concrete or cement. An explanation that says "materials are flat" fits the mineral products and does not fit the metals. Which one applies depends on what the work is made of, and the comparison table is arranged so that a reader can check the categories that matter to a particular estimate rather than a general claim.

Within the metals, the latest month diverges. Copper wire and cable rose 4.2% from July to August and reached its five-year high in August; steel rose 1.7%; aluminum mill shapes fell 4.4% from July after peaking in June. Lumber fell 1.9% in August after a run of increases. One month is not a trend, and BLS marks all six August values preliminary.

The comparison

Context measures, each with its own latest period:

Index levels are not comparable across rows; each series has its own base period. Two-year comparisons, where the record allows them: lumber +18.0% against August 2024; copper wire and cable +45.5%; steel +38.5%; aluminum mill shapes +56.4%; gypsum products +1.6%; ready-mix concrete +2.3%.

Historical charts

Each core index over 5 years, on its own scale, then the raw-metal benchmarks, then the six together rebased to a common start. Charts are drawn from series.csv; every value is in the table under each chart.

Material notes

Standing notes on what each measure covers and what it is not are on the materials page and below the charts. What is new this month, by material:

Softwood lumber is 17.9% above last December but still 7.7% above where it stood five years ago, and far below its March 2022 peak of 540.7. August's 11.8% year-over-year figure follows a +5.5% reading in August 2025 and readings of −6.3% and −18.2% in the two Augusts before that. Lumber's year-over-year figure depends heavily on which August is the comparison.

Copper wire and cable set a five-year high in August at 602.5 and is 18.0% above December. The raw metal rose faster: LME copper is 48.1% above a year ago, against 27.2% for wire and cable, a gap of 20.9 points.

Steel mill products are 22.0% above December after rising in every month of 2026 so far. The index is still 8.9% below where it stood five years ago, near its December 2021 peak of 449.7, and has climbed from a January 2025 low of 261.6.

Aluminum mill shapes fell 4.4% in August from a June high of 394.3. The raw metal did not fall in August: LME aluminum rose 2.8%. The two series moved in opposite directions in the latest month while showing nearly the same year-over-year change (+27.3% and +25.2%, a gap of 2.1 points).

Gypsum products rose 0.7% in August, the third monthly increase in a row after a dip in May, and is 0.2% above August 2025. The narrower gypsum building materials index was unchanged in August and is 0.9% below a year ago.

Ready-mix concrete rose 0.1% in August and is 2.3% above a year ago, while the cement index was unchanged in August and is 1.2% below a year ago. Concrete moved without cement this year.

Standing notes

What each measure covers, why it matters, and what it does not represent. These notes are the same in every edition; the paragraphs above say what is new.

Context

What the evidence shows: the raw-metal benchmarks and the manufactured-product indexes moved in the same direction over the year for copper and for aluminum, and the raw metal moved by more in the case of copper. Cement shipments from U.S. plants for January through April 2026 were 8.3% above the same months of 2025, and April alone was 4.7% above April 2025. Total housing starts in August were 1.2% below a year earlier at a seasonally adjusted annual rate of 1,275 (thousands of units), while single-family starts were 5.2% above a year earlier at 918.

What the evidence does not show: why any of these moved. A higher raw-copper price is a plausible reason for a higher wire-and-cable index, and the timing is consistent with it, but the record here does not establish that the one caused the other or how much of the product's rise the metal accounts for. Steel mill prices rose through a period when trade measures on steel were in the news; this record contains prices, not policy, and does not attribute the rise. Cement shipments rising while the cement index fell slightly is consistent with a market that was busy without being tight, and equally consistent with other explanations the record cannot test.

What the evidence cannot connect: the shipments figure describes April; the price indexes describe August. The four-month gap is the source's publishing lag, and no inference across it is made.

Uncertainty

All six August index values are preliminary. BLS revises the most recent four months of a producer price index, so the August figures quoted here may differ in the next edition, and the September edition of any series can restate July and August.

The USGS shipments figures are marked estimated by USGS and are published about four to five months after the month they describe. The latest month in this record is April 2026, and the comparison with April 2025 relies on a prior-year figure that USGS may itself have revised since it was first published.

The World Bank benchmark is a monthly average of daily exchange settlements in dollars per metric ton. It is a world price, not a U.S. delivered price, and it includes no regional premium or fabrication. The gap between the metal and the product is an observation about two series, not a margin.

Single-family starts rose 7.6% in one month. Census starts are survey estimates with wide sampling error month to month, and the series is revised; a single month's change should be read with that in mind.

The five-year window for the USGS series is limited to what the current workbook holds, which is the current and prior year. Its chart shows 16 months, not 60.

The edition page states which timestamp chain entry covers this edition's files and which authorities' tokens it holds. No OpenTimestamps proof was produced, because the client was not installed where the anchor ran. A timestamp shows the files existed unchanged by a date; it does not show that a source's figure was correct.

What the run flagged

The collection step flags conditions for the editor before the text is written: stale series, large moves, missing comparisons, preliminary values. They are listed as the run produced them.

The record

Four sources were fetched on 24 September 2026 and retained byte for byte: the BLS public API response for the eight PPI series (ten years each), the World Bank's monthly commodity workbook (updated 2 September 2026), the USGS cement workbook for April 2026, and the Census housing-starts time-series workbook. Every figure above appears in numbers.json; the formulas are in dictionary.md; the rows the figures were computed from are in data.csv, and the charted windows are in series.csv. No correction has been made to this edition.