Norwegian Log (Lafet) Wall Calculator
Calculate timber volume and log count for two-sided hewn log homes. Adjusts for effective wall height, notching loss, and wood shrinkage.
Timber Requirement
About
Builders of Norwegian-style log homes (Lafet) face a specific challenge. Unlike round logs, hewn logs have a reduced cross-section, and the intricate notching system significantly reduces the vertical gain per log row. Estimating material based on raw log diameter often leads to a shortage of timber on the job site. This calculator determines the precise Heff (Effective Height) of each tier, accounting for the overlap in the saddle notch and the necessary allowance for drying shrinkage. It ensures you order sufficient linear meters of timber to reach your target wall height after the wood has settled.
Formulas
The calculation of the required number of log rows N depends on the target wall height Htotal and the effective height of a single log heff, adjusted for the shrinkage coefficient kshrink.
Total linear length Ltotal is derived from the wall perimeter P and the number of rows, plus a waste factor w.
Ltotal = P × N × (1 + w)
Reference Data
| Log Diameter (Green) | Typical Notch Overlap | Effective Height (Heff) | Logs per Meter of Wall |
|---|---|---|---|
| 200 mm | 50 mm | 150 mm | 6.67 |
| 250 mm | 60 mm | 190 mm | 5.26 |
| 300 mm | 70 mm | 230 mm | 4.35 |
| 350 mm | 80 mm | 270 mm | 3.70 |
| 400 mm | 90 mm | 310 mm | 3.23 |
| 450 mm | 100 mm | 350 mm | 2.86 |