I feel like this is one of those questions whose answer will either be directly stated somewhere or hidden beyond three layers of conjecture. I'm going to admit outright that this question is prompted by an RPG, but it's something I've actually wondered about before.
Approximately how long in terms of weeks, months etc. would it take to build something like a 2-3 story house in a late medieval/early modern town in Central Europe, with materials readily available (if not literally in a pile) and a reasonable number of hired workers? The parameters aren't too strict, so any reference you have whatsoever can be helpful for extrapolation if nothing else. Even the materials used aren't really decided, but preferably a "high quality" merchant's house as opposed to a wooden hut.
I'm not asking how long it took to build something like a castle or cathedral, but info about farmhouses etc. can be applicable.
This is an interesting question; construction time varied WIDELY, depending on materials, number of laborers, cost, and season. Some architectural historians estimate that in the 16th and 17th century one-room cottages for the very poor in the north of England (cheaper than the south) could be thrown up in around half a week and cost as little as 2 pounds.
Another example might shed some light: a less ramshackle dwelling involving a skilled artisan and some specialized construction--not a house, but should give you an estimate for a mid-sized wooden building in sixteenth-century England. In 1594, the Earl of Shrewsbury arranged to borrow a carpenter for six weeks to build a mill. You can see the relevant estate record in the Shrewsbury papers held online at the National Archives [here.] (http://discovery.nationalarchives.gov.uk/details/r/204858ce-a6c7-474c-90a6-c3cb9e2b2c8b). Mills were serious, complicated buildings that served whole mini-regions (much to tenants' annoyance--they were often accused of abusing their effective monopolies), and a small multi-room house would take much less time.
A final data point: during the English settlement/invasion of Ulster in the early seventeenth century, reports were sent home to document the success of the plantations. One such report (1611) noted that one nobleman and his tenants had erected 28 houses between May of one year and July of the next. In this case there would have been an imperative for speed (and also possibly for some exaggeration in the report, but set that aside). Unfortunately the report does not actually tell us much about rate (were all 28 houses being built simultaneously, each taking 14 months? were they built in sequence, one every two weeks? or is the answer between those two poles?)
Hopefully these answers give some context, if not precisely what you wanted!