takeoffmetric-prolog

Dependency-free SWI-Prolog pack (standard libraries only) that embeds version 1.2.0 of the US construction estimating constants published by TakeoffMetric as read-only records: bag yields, aggregate and soil densities, swell and compaction ratios, rebar weights, dressed lumber sizes, block counts, shingle coverage, asphalt unit weights and air properties. These are published constants with their sources, not original research: each record gives the value, its unit, an SI conversion, the condition it applies to and the source it was read in.

It is a port of the Go module takeoffmetric-go: same table, same lookups. The tests compare every record, the search results and the source list to vectors written by the Go module.

55 of the 148 records carry no value: their publishers do not allow republication. Those records keep the quantity, its unit and the link to the source; withheld is true, the dict has no value and no value_si key, and withheld_hosts lists the domains concerned. Read the value at the URL of the source.

:- use_module(library(takeoffmetric)).

?- by_id('CON-007', C).              % fails when the id is unknown
?- search("bank density", Rows).
?- all(All).
?- sources(Sources).

Each record is a dict with the keys id, category, material_or_item, quantity, value, value_text, unit, value_si, unit_si, condition, source (a dict: publisher, title, url, type), date_opened (a term date(Y, M, D)), used_by_tool_url, engine_file, engine_symbol, notes, withheld and withheld_hosts. Text values are strings; value and value_si are floats.

The pack is a lookup library and computes nothing. To turn dimensions into quantities, use the calculators on the site, for example the concrete calculator. How they use these values: methodology.

Estimating values only: confirm with your plans, your supplier and your local code before ordering or building.

Tests

From the pack root:

swipl -g run_tests -t halt test/test_takeoffmetric.pl

Updating the data

`python sync_data.py copies ../TakeoffMetrics-go/data/constants.csv` (or the file given as first argument) into `data/`, which prolog/takeoffmetric.pl reads when it is compiled and stores as facts. It accepts only the 1.1.x header (with values_withheld and withheld_hosts). Then regenerate test/vectors.json from the Go module and run the tests.

Licence

• Code: MIT, see LICENSE.
• Constants (`data/` and the facts compiled from it), see data/LICENSE:
  • the compilation (selection of rows, SI conversions, conditions, notes, column structure): CC BY 4.0, attribution TakeoffMetric Editorial;
  • values from federal publications: works of the US government, in the public domain;
  • any other value stays under the terms of its publisher and is not relicensed by CC BY 4.0; each row names its publisher and links its source (source_publisher, source_title, source_url);
  • 55 rows carry no value (values_withheld = true): their publishers do not allow republication.
• Cite as: TakeoffMetric Editorial, US Construction Estimating Constants, version 1.2.0, 2026, takeoffmetric.com.
• The calculation engine of takeoffmetric.com is not included in this pack.