Here is a video of the Japanese Tea house being put together, probably filmed over a period of around 4-5 hours. The Japanese carpenters are very precise and each part actually went together and was taken apart again several times until they were satisfied with the fit.
It is difficult to estimate how long it took to prepare the timbers, but it was made entirely from trees that were felled on the worksite and converted using hand tools. The Japanese carpenters had done quite a bit of background work before we got there and then a mixed Japanese / European group of 15-20 people spent a solid seven days of work on it before this final construction.
My previous post shows step-by-step photographs if you want to understand what is happening in detail.