I would like to post questions about building and hanging a garden gate. I think this site is the best fit but I cannot see any similar questions. The Home Improvement site is the alternative but a garden gate seems too small scale and garden-related to the other questions on there.
The page in the help center that describes on- and off-topic subjects has an entry for this in the off-topic section:
the framing, plumbing or electrical aspects of building greenhouses, decks, or other structures (try Home improvement)
(Disclaimer: the "or other structures" part used to be "etc." until I changed it just a few minutes ago while making another edit.)
1. Source: I'm a moderator there as well. If anyone gives you guff, let me know and I'll smite them!