Re: building codes / standards
Your best bet is to speak directly with the Bauamt (or whatever the equivalent is in French - the building department of your local community government). Rules and regulations will vary by canton and community. Moreover, how those rules and regs are applied (or ignored) may also vary, even within the same community.
Other people's experiences, while helpful in pointing out the most likely path you should take, cannot guarantee that you are in compliance within your own community. The local authority is the final arbiter. Go talk to them, bring along a fluent speaker if you are not.
Yes, navigating one's way through the jungle of permits, regs, unwritten 'rules', neighborhood agreement, selective interpretation, that is needed to build just about anything here can be frustrating. I wish you all the best with your project.