The rule of thumb I used to use as a draughtman was that plans would be metric for zoning and permit approval, metric for steel-frame or concrete, and US standard measurement for lumber and wood-frame. this is because dimensional steel mostly comes from China, which is sold in metric lengths, while lumber is cut to US standards.
The rule of thumb I used to use as a draughtman was that plans would be metric for zoning and permit approval, metric for steel-frame or concrete, and US standard measurement for lumber and wood-frame. this is because dimensional steel mostly comes from China, which is sold in metric lengths, while lumber is cut to US standards.