Attribute Schema Library
Attribute schemabuilding materials & lumber

Dimensional Lumber Attributes

Dimensional lumber is softwood sawn to standard nominal sizes — 2x4 through 2x12, 4x4 and up — then surfaced, graded, and sold to framers, truss and component plants, and GCs through lumberyards, pro dealers, and building materials distributors. Commodity in price, anything but commodity in data.

The spec lives in three places that rarely agree: the grade stamp (species group, grade, mill number, agency, seasoning), the treater's end tag (preservative, use category, retention), and the agency rule book (design values, which change with grade and with width). None of it arrives as a file — mills ship a stamp, treaters staple a tag, and the ERP carries a description like 2X4-92-5/8 SPF STD&BTR KD.

Variant explosion does the rest. Size × length × species group × grade × seasoning × preservative × use category is a separate sellable item, and length is sold two ways: random tally and precision-end-trimmed precut. Rule books move too — Southern Pine design values were republished effective June 1, 2013, and records built before that quote numbers the book no longer contains.

Core

Every SKU needs these. Without them the record is not a product, it is a row.

Nominal Size
enum
2x6

The trade name and the first filter every buyer touches. Never the real dimension — a 2x4 is 1-1/2 x 3-1/2 dry.

Actual Dressed Size
text · in
1-1/2 in x 5-1/2 in (dry, S4S)

PS 20 minimum dressed size. Drives span tables, hardware fit, drywall layout, and freight cube. Dry and green have separate size schedules.

Length
number · ft
16 ft

Random tally ships in even lengths 8-20 ft. Precuts are called out in inches. The wrong length is a return, not a cut.

Species / Species Group
enum
Spruce-Pine-Fir (SPF)

Design values, weight, and treatability are assigned to the group, not the tree. SPF, DF-L, Hem-Fir, and Southern Pine are not interchangeable.

Grade
enum
No. 2 & Btr

Sets allowable knots, wane, and slope of grain, and with them the design values. No. 2 is the framing default; Select Structural carries a premium.

Grade Category (NGR Size Classification)
enum
Structural Joists & Planks (2x5 and wider)

National Grading Rule scope. 'No. 2' under Light Framing and under Structural Joists & Planks are different grades with different values.

Seasoning / Moisture Designation
enum
KD-HT (MC 19% max)

KD and S-DRY are 19% MC or less, MC15 is 15% or less, S-GRN is unseasoned and shrinks in service. HT is a separate heat-treatment claim.

Surfacing & Edge Profile
enum
S4S, eased edge (E/E)

S4S is the default, but rough and S1S2E exist. Eased edge versus square edge is specified on exposed framing and decking.

Selling Unit of Measure
enum
PC (piece); price basis MBF

Pro dealers quote per MBF, home centers per piece, some items per linear foot. A price without its UOM is a claim, not a quote.

Manufacturer Part Number
identifier
2X4-92625-SPF-STDBTR

Mill or treater item code. The join key between the supplier's price file and the distributor's SKU record.

GTIN / UPC
identifier
00012345678905

Required for scanning at the yard and for any retail or marketplace listing. Random-length tally items frequently carry none.

Differentiating

What buyers actually compare on. This is where catalogs win or lose the filter.

Preservative Type
enum
MCA (micronized copper azole)

MCA, ACQ, CA-C, and SBX are not substitutes. Copper systems drive fastener and connector selection; borates are interior, non-weather-exposed only.

AWPA Use Category
enum
UC4A (ground contact, general use)

AWPA U1 use category is the actual buying decision: above ground, ground contact, or permanent wood foundation. Printed on the end tag.

Preservative Retention
number · pcf
0.15 pcf (ACQ), UC3B

The number behind the use category. 0.15 ACQ and 0.06 MCA are both UC3B; a retention without the preservative named is unreadable.

Bending Design Value (Fb)
number · psi
925 psi (Southern Pine No. 2, 2x8)

What engineers and component plants specify against. Varies by grade and by width — it is not a property of the species alone.

Modulus of Elasticity (E)
number · psi
1,400,000 psi (Southern Pine No. 2)

Governs deflection, which usually fails a joist span before strength does. Paired with Emin for stability checks.

Compliance & identifiers

Standards, regulatory data, and the identifiers channels reject you for missing.

Grading Agency & Mill Number
identifier
SPIB / Mill 217

ALSC-accredited agency mark plus the mill's own trademark. The inspector reads the stamp, and code acceptance depends on it.

Country of Origin
enum
Canada

Canadian softwood lumber carries antidumping and countervailing duties. Origin also drives customs entry and is required for GDSN and retail item setup.

The fields that aren't in the schema at all

What most dimensional lumber catalogs are missing.

The table above is the schema most catalogs already have. These are the attributes that usually aren't in it — each one surfaced by a signal from the live market rather than by an audit of what's already there. This is what Anglera's Schema Foundry does on a real catalog, in this category.

Search signal
+ Actual Piece Length / Precision End Trim (PET)

Buyers search '92-5/8 stud' and '104-5/8'. Catalogs list an '8 ft stud' with no field for trimmed length or PET tolerance, so precut studs and random-length 8-footers collapse into one SKU.

A framer ordering an 8 ft stud for an 8 ft wall receives 96 in random-length and cuts every piece, or refuses the load. The precut premium is invisible and unbillable.

Supplier signal
+ AWPA Use Category and Retention

Every treater's end tag carries use category and retention in pcf. Distributor records carry a single 'Treated: Yes/No' flag, so UC3B above-ground and UC4A ground-contact stock look identical.

Above-ground material ships to a ground-contact application. The failure surfaces years later as a callback, and the paper trail points at the distributor.

Competitor signal
+ Design Values (Fb, E, Emin)

Component plants and engineers specify by Fb and E, then phone in to ask. No distributor filter rail exposes them; the numbers sit in agency rule books and NDS supplement tables.

Every design-value question becomes a phone call. Truss and component-plant quotes go to whoever can answer from a screen instead of a callback.

Supplier signal
+ Grade Rule / Design Value Edition

Southern Pine design values were republished effective June 1, 2013. Records seeded from older spec sheets still quote superseded numbers, with no field recording which edition they came from.

A superseded Fb published as current is a spec error the distributor put in writing. Nothing in the record flags the value as stale.

Marketplace signal
+ Chain-of-Custody Certification

Institutional and LEED-tracked jobs ask for FSC or SFI certified content and a CoC number. Most lumber catalogs carry no certification field at all — only a logo in a PDF brochure.

The item cannot be offered on jobs with a certified-wood requirement. The bid is filtered out before anyone reads the price.

How Schema Foundry finds these

Messy in, governed out.

The same value, spelled every way building materials & lumber suppliers spell it. A filter only works once they agree.

Species / Species Group
SPFS-P-FSpruce Pine FirSPRUCE/PINE/FIRSPF-SSpruce-Pine-Fir (South)
Spruce-Pine-Fir (SPF)

SPF-S (South) is a separate species group with lower design values. Collapsing it into SPF publishes strength the lumber does not have.

Grade
#2No.2NO 22 & BTRNo.2&BtrSTAND&BTR
No. 2

'No. 2 & Btr' is a shipping mix, not a grade, and 'Stand & Btr' is Light Framing. Neither one normalizes to No. 2.

Seasoning / Moisture Designation
KDKDHTKD-HTS-DRYMC15S-GRN
KD-HT (MC 19% max)

KD and S-DRY both mean 19% MC or less; MC15 means 15% or less; S-GRN is unseasoned. HT is a heat-treatment claim, not a moisture level.

Preservative Retention
0.15.15 pcf0.15 lb/ft30.06 MCAGround Contact2.4 kg/m3
0.15 pcf (ACQ)

Retention only reads correctly with the preservative named: 0.15 ACQ and 0.06 MCA are both UC3B. A bare 0.15 cannot be filtered on.

What buyers ask

Every one of these should be answerable from the attributes above. If it isn't, that's a gap.

  • Is this No. 2 or No. 2 & Btr, and whose stamp is on it?
  • Is that a true 92-5/8 precut stud or a random-length 8-footer?
  • Ground contact rated, or above ground only?
  • What's the Fb and E — will these 2x10s make a 16 ft span?
  • Kiln dried or green? Is it going to shrink after it's up?
  • Plans call for DF-L. Can I substitute SPF at the same size?
  • Is that price per piece or per MBF?
  • Does it carry FSC or SFI chain of custody for a LEED job?

What channels require

The same SKU, different mandatory fields per destination.

Distributor site & ERP faceted search
Nominal SizeActual Dressed SizeLengthSpecies / Species GroupGradeSelling Unit of Measure
GDSN / 1WorldSync building materials pool
GTINGPC brick codeBrand & MPNNet content and UOMPackage hierarchy & dimensionsCountry of Origin
Home Depot / Lowe's Pro item setup
GTIN & MPNNominal and actual dimensionsSpecies / Species GroupGradeTreatment type & use categoryCA Prop 65 warning
Amazon Business — Building Supplies
GTINBrand & MPNItem dimensions & unit countMaterial / speciesCA Prop 65 warning

Dimensional Lumber data, in practice

Why doesn't 'No. 2' mean the same thing on a 2x4 and a 2x12?

Because design values are assigned by grade and by width, inside a National Grading Rule size classification. Southern Pine No. 2 is Fb 1,100 psi at 2x4, 925 psi at 2x8, and 750 psi at 2x12 — same grade, same species, three different numbers. The 2x2 through 4x4 range is graded under Light Framing and Structural Light Framing rules; 2x5 and wider falls under Structural Joists & Planks. A record that stores Grade = 'No. 2' and stops there has captured a label, not a property. Store the size classification and the width-specific design values alongside it, or every span question becomes a phone call.

Should the record carry nominal size, actual size, or both?

Both, and you cannot derive one from the other with a rule you can hardcode. PS 20 sets minimum dressed sizes and publishes separate schedules for dry and green lumber: a dry 2x4 is 1-1/2 x 3-1/2, a green one is 1-9/16 x 3-9/16 — same nominal call, different material. Nominal is what the buyer searches and what the plans say. Actual is what drives span tables, hardware fit, drywall layout, and freight cube, and PS 20 requires bills and invoices to show actual net size. Rough-sawn and resawn items break the mapping outright.

Is 'treated' one attribute or several?

Three at minimum, and they answer different questions. Preservative type (MCA, ACQ, CA-C, SBX) determines fastener and connector compatibility — copper systems demand hot-dip galvanized or stainless. AWPA use category (UC1 through UC4C) is the application decision: UC3B above ground exposed, UC4A general ground contact, UC4B critical structural, UC4C permanent wood foundation. Retention in pcf is the number behind the category and only reads correctly beside the preservative: 0.15 ACQ and 0.06 MCA are both UC3B. A 'Treated: Yes' boolean answers none of these — and all three are already printed on the end tag the treater ships.

What happened to Southern Pine design values in 2013?

SPIB republished design values for visually graded Southern Pine dimension lumber effective June 1, 2013, following in-grade testing, approved through the ALSC process. Select Structural, No. 1, No. 2, and No. 3 all moved, and most values came down. Any spec sheet, span table, or catalog record seeded before that date can still be carrying superseded numbers, and nothing in a typical PIM record says which edition of the rule book a value came from. If you publish design values, publish the source and the edition with them. That field is what makes the value auditable later.

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