Timber Calculator for House and Sauna
About Timber Calculation
This calculator estimates the required volume of timber (m³) for building walls of a house or sauna made of solid timber. It evaluates external walls, internal partitions, gables, allowances, and related quantities such as total weight, number of courses, and dowels. The calculation is intended for preliminary material planning using nominal timber dimensions.
Tips and Tricks
Wall geometry as a basis. The calculation starts from the building plan geometry: overall length A, width B, and wall height H (mm). From the selected wall layout option, the calculator determines the total length of external walls and, if applicable, the total length of internal partitions. All areas are derived from these linear dimensions multiplied by the wall height.
Timber thickness and wall area. External and internal walls may use different timber widths (mm), which define the wall thickness on the plan. The total wall area (m²) is obtained as wall length multiplied by wall height, with gable areas added when this option is enabled. Openings are not deducted, which is typical for volume-oriented timber estimates.
Courses and working height. Timber is laid in horizontal courses. The number of courses is calculated by dividing the wall height H by the working timber height (mm), which accounts for joints and settlements. This value may differ from the manufacturer's nominal (overall) timber height, but the number of courses is always based on the working height.
Timber volume for purchase. The timber volume is calculated using the overall timber height, not the working height. For each course, the volume equals wall length × timber width × overall timber height. Summing all courses gives the total timber volume in m³. This reflects how timber is actually purchased and supplied.
Allowance and gables. A percentage allowance is applied to the calculated timber volume to cover trimming, fitting, and waste. If gables are included, they are treated as triangular walls with area width × height / 2 and the same thickness as the external walls, adding both area and volume to the result.
Weight and loads. Timber weight is obtained by multiplying the final volume by the selected wood density (kg/m³). From this weight, the calculator derives simplified linear loads on walls (kN/m) and an average pressure on the foundation (kPa). These values are indicative only and do not replace structural design calculations.
Dowels and auxiliary quantities. The number of dowels is estimated from total wall length, dowel spacing, and the number of courses minus one. Recommended dowel diameter and length are derived from timber height and thickness using common construction practice.
FAQs
Why are working height and overall timber height different?
The working height reflects the actual height of one course in the wall, including joints and compression. The overall height is the manufacturer's nominal size and is used to calculate how much timber must be purchased.
Why are openings not subtracted from the wall volume?
In timber construction, openings usually generate offcuts and short pieces that cannot be fully reused. Ignoring openings gives a more realistic estimate of required material volume.
How accurate is the dowel calculation?
The dowel quantity is an approximate guideline based on spacing and number of courses. Actual requirements may vary near corners, openings, and according to the chosen assembly technology.
Does wood density affect the timber volume?
No. Density affects only the calculated weight and derived loads. The timber volume depends solely on geometry and allowances.
Can this calculator replace a full material specification?
No. It provides a solid preliminary estimate. Final specifications should consider detailed drawings, moisture content, profile type, shrinkage behavior, and local building regulations.