House Material Estimator

Purpose and model boundary

This calculator estimates the materials and their cost for a whole house you draw. You draw the house level by level in the drawing tool: a basement, up to three floors and the roof. The page sends each part to its own calculator, and this spreadsheet combines their answers into one priced material list with a total.

The parts and their calculators are:

• The basement: the Basement Material Estimator, for the concrete and the other basement materials.
• The walls of each floor: the Framing Lumber Estimator, once per floor.
• Each framed floor: the Floor Framing Estimator, once per floor system. It is drawn on the level below the floor it carries.
• The roof: the Roof Framing Estimator, for the roof framing lumber and sheathing.
• The finishes: the Flooring Tile Calculator for each level with floored rooms, the Siding Exterior Trim Calculator for each floor, and the Roof Area From Plan Calculator for the roofing.

The spreadsheet checks that every answer belongs to the same drawing, keeps the house inside the code scope it names, and lists every material line once by level and once combined. It adds a contingency and sales tax to the materials total.

It is an estimate for buying materials, not a structural design or a code-compliance review, and it certifies no structure. It does not price labour, delivery, permits or fees.

Inputs and units

The drawing is the first input. Each level is drawn in the drawing tool, and the page reads it on Calculate.

What the page sends. On Calculate the page sends the spreadsheet:

• The level tables: the levels, how they stack, the stories, the stairs and their flights, the outline's grade segments, the limits echo and the status rows.
• Each calculator's answer for its level, with its request and result details: the calculator, its contract, the request key, the unit system and the drawing generation.

The spreadsheet does not draw or measure the house. It re-checks every table and answer before it prices a line.

The site answers:

• Seismic Design Category: A, B, C, D0, D1, D2, E or unknown. Unknown is treated as D2 for the story limit; it is not a professional assessment.
• Wind design required: No, Yes or unknown.
• Ground snow load: up to 70 psf, over 70 psf, or unknown.

Each answer starts as unknown.

Units. One Units choice, US or Metric, applies to the whole house. The request for each level carries the same unit system. Lengths are in feet under US and metres under Metric, and floor areas in square feet or square metres.

Each calculator's options. The House page shows each calculator's own options, less the ones the drawing sets.

Contingency and sales tax. Each is a fraction of the materials total: contingency from 0 to 50%, sales tax from 0 to 25%. Both start at 0.

Prices.

• The House price panel prices the wall framing (studs, plate sticks, wall sheathing sheets, nails and the double 2x6, 2x8 and 2x10 headers), the roof framing (lumber per board foot or cubic metre, and sheathing sheets) and the finishes (flooring, siding and trim, and roofing). The panel has 34 prices.
• The basement is priced with its own 25 prices, which start at the Basement Material Estimator's typical figures. Only the prices of the unit system in use are read.
• The floor framing lines carry the prices set in the floor framing options.

The prices are illustrative typical retail prices (2026-10-31), not a quote. Replace them with your supplier's prices. A typed 0 is a price; a blank price leaves its lines listed but not priced.

Governing relationships

Each line comes from a calculator. Every material quantity is the calculator's own answer for the same drawing and generation. The page computes no quantity or cost. An answer that is missing, stale, cancelled or failed never becomes a line of zeros.

Each line is priced once.

• Wall framing lines are priced from the House panel. The headers are counted one assembly per window or door opening.
• Roof framing lumber is priced per board foot (US) or cubic metre (Metric), on the volume the roof calculator returns, not on the number of stock pieces. Special-order members have no cost.
• Flooring, siding and roofing lines are priced from the House panel, since the finish calculators return quantities only.
• Other lines use their own stated price unit.

Line cost = quantity × unit price, for a line with a price.

The combined list. A line combines with another only when the source calculator, item, size and unit all match. Equal descriptions from different calculators never combine. A combined line's cost is the cost of its priced lines.

Siding is estimated floor by floor and merged into one house-wide set of lines. The spreadsheet checks the merged lines against the sum of the floors. The siding itself is ordered in whole squares (100 sq ft, or 9.290304 m²), the siding calculator's squares to order, and priced per square, so its cost does not depend on the board size entered there.

The totals. c is the contingency rate and t the sales tax rate.

Materials total = the sum of the priced lines

Contingency = materials total × c

Sales tax = materials total × t

Total cost = materials total + contingency + sales tax

Contingency and sales tax apply once, to the materials total only.

Calculation sequence

1. The page asks each level's calculator for its answer and waits for every one from the same drawing.
2. The spreadsheet checks the site answers and the scope limits.
3. It checks the level tables against each other, and each answer's request and result details against the drawing.
4. It reads each answer's material lines and prices them.
5. It lists the lines by level, combines them, and adds the totals.

Outputs and interpretation

The results show:

• The status line.
• The money: the materials total, the contingency amount, the sales tax amount and the total cost.
• The floor area of the basement, each floor and the attic, and in total.
• The stories above grade plane.
• The material list: one line per level and material, with its level, trade, item, size, quantity, unit, unit cost, cost and price state. The levels are the basement, Floors 1 to 3, the roof, and a house-wide level for the siding.
• The combined list: the same materials across the house, with source, trade, item, size, quantity, unit, cost of the priced lines and price state.
• A note on unit costs beside both lists. A roof framing line's cost is its volume times the lumber price, so its quantity times its unit cost does not give its cost.
• Two charts: cost by level and cost by trade.

The trades are concrete, reinforcement, formwork, earthwork, drainage and moisture, anchors, wall framing, floor framing, roof framing, flooring, siding and trim, and roofing.

Validation and status logic

The status shows above the results. It reads one of three things:

• NOT VALID: no estimate; the reason says what to fix.
• CHECK: an estimate with something to look at.
• OK: nothing to report.

The first matching case wins.

NOT VALID, in this order:

1. Outside the scope. The house is outside the code limits that house mode models, and needs an engineered design under the International Building Code. The status names the first limit it breaks:
   • Seismic Design Category E;
   • wind design required;
   • a ground snow load over 70 psf;
   • more stories above grade plane than allowed: three, or two in Seismic Design Category D2 or when the category is unknown;
   • the stairway rules;
   • a wood story or unsupported stud height over the limit.
2. A calculator could not calculate its part. The status names the level and the calculator, gives its reason, and asks you to fix that level.
3. Framed basement walls. These are not estimated yet. Remove the basement framing and estimate those walls separately.
4. A missing or stale answer. The floor framing for a floor, a floor's wall framing, or the basement estimate is missing or was made for another drawing. Open that part and press Calculate.
5. Missing level tables. The levels' tables are missing or were made for another drawing; press Calculate.

With no house drawn, the status is the last of these, and every figure reads 0.

CHECK, in this order:

1. A level's outline does not match the level below. The part that differs is not framed or priced.
2. The walkout wall's wood framing is not estimated. Its concrete edge is included, but its studs, plates and sheathing are not.
3. The site's wind design need is not known. If the site requires wind design, the estimate does not apply.
4. Some materials have no price entered. The status names their trades, and the total covers the priced lines only.
5. Interior bearing walls on the basement slab need footings, which are not estimated.
6. The ground snow load is not known. Confirm it is 70 psf or less.
7. A calculator's answer carries a CHECK. The status names the level and the calculator and gives its text.
8. A stair has a check from the drawing tool.

Assumptions and limitations

• The quantities are the calculators' own. Each part's rules, defaults and limits are those of its calculator.
• Stories and stairs are checked for fit only. Story heights, habitable attics and the stairs drawn (width, headroom, risers, treads, winders and landings) are checked against the limits held in the spreadsheet. Stair materials are not estimated.
• Floor 1 has a floor framing estimate only when it sits over a basement.
• Not modelled:
  • loads, spans, member sizing, bearing, connections and fasteners (each calculator takes its member sizes from professional inputs or its own defaults);
  • lateral bracing design;
  • footings other than the basement's;
  • framed walls in the basement, and the wood framing of a walkout wall;
  • egress, fire separation and other non-structural code requirements;
  • windows, doors, insulation, mechanical, electrical and plumbing;
  • labour, delivery, permits, fees and price changes.
• The prices are illustrative. They vary by place and date.

Restrictions and non-computing states

Nothing is priced or totalled while the status is NOT VALID. Every figure reads 0.

The spreadsheet does not trust the page. It re-checks every table and every answer, and refuses a table or answer that is missing, stale, or made for another drawing or unit system.

The structure must be designed or checked by a qualified structural professional. Check every quantity against the approved plans and with your supplier before ordering.

Errors and warnings

Each NOT VALID line names what to fix, and each CHECK line names what to look at. A calculator's own reason is shown in the status with its level and its calculator's name.

Sources and further reading

• International Code Council, 2021 International Residential Code. The spreadsheet cites these sections by number and reproduces no table. Where the 2024 edition numbers a limit differently, the spreadsheet notes it.
  • Sections R101.2 and R301.2.2.7: stories above grade plane.
  • Section R301.2.1.1: wind design.
  • Section R301.2.2: seismic design category.
  • Section R301.2.3: ground snow load.
  • Section R301.3: story height.
  • Section R202: definitions.
  • Section R326.3: habitable attics.
  • Section R311.7: stairways.
  • Section R407.3: columns, in Chapter 4, Foundations, on UpCodes. up.codes
  • Sections R502.4, R502.6 and R502.10: floor framing, in Chapter 5, Floors, on UpCodes. up.codes
  • Tables R602.3(5), R602.7 and R602.10.3, in Chapter 6, Wall Construction, on UpCodes. up.codes
• National Institute of Standards and Technology, NIST Guide to the SI, Special Publication 811, Appendix B.8. nist.gov. It gives the foot (0.3048 m) and the pound (0.45359237 kg) behind every conversion.

Each part's own rules and sources are listed with its calculator: the Basement Material Estimator, the Framing Lumber Estimator, the Roof Framing Estimator, the Flooring Tile Calculator, the Siding Exterior Trim Calculator and the Roof Area From Plan Calculator.

What the defaults are.

• The house: none is drawn, so the status asks you to press Calculate and every figure reads 0.
• Site answers: each starts as unknown. An unknown wind design need or ground snow load gives a CHECK. An unknown seismic category is held to the Seismic Design Category D2 story limit.
• Scope limits: the limits held in the spreadsheet, compared with the drawing tool's limits echo.
• Contingency and sales tax: both 0.
• Prices: every price is an illustrative typical retail price (2026-10-31), not a quote. One currency serves both unit systems, and the metric prices are conversions. The basement prices are the Basement Material Estimator's typical figures. Replace every price with your supplier's.

The House panel's starting prices:

Siding is priced per square, so its cost does not depend on the board size entered in the siding calculator. The 120 per square is derived from the price record's vinyl lap siding board: 9.98 for a board 150 in long with an 8 in exposure, which covers 150 × 8 = 1,200 sq in, or 8.333 sq ft. That gives 9.98 ÷ 8.333 × 100 = 119.76 per square, rounded to whole dollars (the record's rule at 20 and above) to 120.

These sources describe the code text and the units; they certify no particular house or result.