construction-utils

Construction calculation utilities for building projects — measurements, materials, lumber, drywall, paint, roofing, slope, and cost estimation helpers.

Part of the www.slabcalc.co ecosystem. For concrete-specific calculations, see the concrete-calculator package or the online Concrete Slab Calculator.

Install

npm install construction-utils

Quick Start

import { squareFootage, drywallSheets, paintGallons, addMarkup } from "construction-utils";

const area = squareFootage(20, 15);       // 300 sq ft
const sheets = drywallSheets(area);        // 11 sheets (10% waste)
const gallons = paintGallons(area, 2);     // 2 gallons (2 coats)
const price = addMarkup(sheets * 12, 15);  // $151.80 (15% markup)

API Reference

Measurements

| Function | Description | |---|---| | squareFootage(length, width) | Area in sq ft | | perimeter(length, width) | Perimeter in linear ft | | circleArea(diameter) | Area of a circle | | triangleArea(base, height) | Area of a triangle | | roofArea(length, width, pitchRise?) | Roof area adjusted for pitch |

Construction Math

| Function | Description | |---|---| | gradePercent(rise, run) | Slope as percentage | | roofPitch(rise, run?) | Pitch string (e.g., "6:12") | | angleFromSlope(percent) | Degrees from slope % | | slopeFromAngle(degrees) | Slope % from degrees | | hypotenuse(rise, run) | Rafter/stringer length |

Lumber

| Function | Description | |---|---| | boardFeet(thickness, width, length) | Board feet for pricing | | studsNeeded(wallLength, spacing?) | Stud count (default 16″ OC) | | plateLength(wallLength, double?) | Linear ft of plates |

Drywall

| Function | Description | |---|---| | drywallSheets(sqft, waste?) | 4×8 sheets needed (default 10% waste) | | jointCompound(sqft) | Gallons of mud | | drywallTape(sqft) | Feet of tape |

Paint

| Function | Description | |---|---| | paintGallons(sqft, coats?, coverage?) | Gallons needed (default 400 sqft/gal) | | primerGallons(sqft, coverage?) | Primer gallons (default 300 sqft/gal) |

Flooring

| Function | Description | |---|---| | flooringSqft(length, width, waste?) | Material sq ft with waste factor | | tileBoxes(sqft, sqftPerBox?) | Number of tile boxes |

Insulation

| Function | Description | |---|---| | insulationBatts(sqft, sqftPerBundle?) | Batt bundles needed |

Unit Conversions

| Function | Description | |---|---| | feetToMeters(ft) / metersToFeet(m) | Length conversion | | inchesToCm(in) / cmToInches(cm) | Length conversion | | sqftToSqm(sqft) / sqmToSqft(sqm) | Area conversion | | psfToKpa(psf) / kpaToPsf(kpa) | Pressure conversion |

Pricing Helpers

| Function | Description | |---|---| | addMarkup(cost, percent) | Apply markup | | tax(subtotal, percent) | Tax amount | | totalWithTax(subtotal, percent) | Subtotal + tax | | unitCost(total, qty) | Per-unit cost | | bulkDiscount(qty, tiers, unitPrice) | Tiered bulk pricing |

Namespace Imports

Group functions by category:

import { measurements, lumber, drywall, paint, pricing } from "construction-utils";

const area = measurements.squareFootage(20, 15);
const bf = lumber.boardFeet(2, 6, 8);          // 8 board feet
const sheets = drywall.drywallSheets(area);
const gallons = paint.paintGallons(area, 2);
const total = pricing.totalWithTax(500, 8.25);  // $541.25

Common Projects

| Project | Functions to use | |---|---| | Frame a wall | studsNeeded(), plateLength(), boardFeet() | | Hang drywall | drywallSheets(), jointCompound(), drywallTape() | | Paint a room | squareFootage(), paintGallons(), primerGallons() | | Install flooring | flooringSqft(), tileBoxes() | | Estimate roof | roofArea(), roofPitch(), hypotenuse() | | Grade a driveway | gradePercent(), angleFromSlope() | | Bid a job | addMarkup(), totalWithTax(), bulkDiscount() |

For concrete work — slabs, footings, cylinders, stairs — use the Concrete Slab Calculator or the concrete-calculator npm package.

TypeScript

Full type declarations included — zero config needed.

import { boardFeet, type BulkDiscountResult } from "construction-utils";

Related

• www.slabcalc.co — Online concrete & construction calculators
• Concrete Slab Calculator
• Concrete Footing Calculator
• Concrete Column Calculator
• Concrete Stairs Calculator
• concrete-calculator — Concrete volume & bag estimation (npm)
• py-concrete-calc — Python concrete calculations (PyPI)

License

MIT — SlabCalc.co