I've been in the construction business for 15 years. And have owned 2 of my own houses that we recorded in (and I made framing changes and added electrical outlets, and built new rooms). As far as I know it really matters where (what state & county) you live in, as to which type of zone your in. Depending what county you lived in they zone them all differently.
When I lived in VA, they would not let you run a business out of your own house.
But here in PA, it looks like you can run a business of of a dog house. You'll just be riding down a quite neighborhood and all of a sudden there's a house that looks like all the rest but they sell Muffler parts. And the next block it's the same thing, but some old couple run's a Deli out of their house.
You gotta probe around. Don't call up the commisoner for the county on the phone and tell him what you are trying to do. His job is to make money for the county. Most of the time there is a min. spending amount for building. That way they can charge you more taxes for the property. What I mean is...in Henrico county, VA. If you spend more than $50 on improvements to your house you were supposted to "get a premit". And you could get in legal touble if you were without a premit. But if you told them you were gonna do between $5000 and $20,000 dollars worth of work, then they wanted "blue prints" and floor plans, and more money! And then there would be framing inspections, and electrical insp. and after you are done the county wants to come look at what you did..Not because they care, but because NOW your house is worth more, and you will have to pay more taxes on what it is now worth.
Then when I moved (just 5 miles away to a Richmond) none of that stuff was important because the county was different and the laws for building were not that strict.
Good luck

Building codes and what you can legally do in your home vary widely from city to city and even within a city there are different "zones". In some cities it is possible for you to have a business in your house if it does not pollute, does not make noise and you don't have more than three cars, not belonging to you, in your driveway at anyone time. In other cities or parts of cities you may not operate a business out of your house no matter how invisible you are. Across town or across the street you maybe able to operate a business that is dealing directly with the public such as a Chinese take out or medical/dental office.

It all depends on the local government and how they have the town "zoned" and where your dwelling is within that zone.

You can usually ask about the zoning of the city though persons concerned with that zoning. I would echo "its that guy again" in that you don't want to tell them you are building a recording studio but you are wanting to know what is possible in the part of the city your house is located in. After you confirm that you can have a business in your building you will have to obtain the proper building permits and if the building is going to be "renovated" you may have to have an architect and structural engineer involved so you don't make the building unsafe buy cutting out the wrong framing members.

Even though you peronally may know what you are doing the city has to protect itself from people who do not know what they are doing and that is the reason for the architect and the structural engineer passing on the project.

Doing any remodeling or revamping without a building permit can be very costly and you could find yourself having to rip out all the drywall after the fact so the building inspector can look at the framing and the electrical work if you are found to be doing the work without a permit. You could also be fined and made to restore the building to its former construction. Once you are on the cities "offender's list" you will be watched more closely in the future. In some cities there are "under the table" payoffs and consultant's fees that will have to be paid to the building inspector or other members of the city government for you to even get a permit.

I know of a person who wanted to put a small business in their house but had to comply with the local politically correct building codes including a ramp into their house and a separate handicapped access bathroom. The person was simply doing tax returns in their house and wanted to add on a separate room to work with clients. He was not prepared for the $$$ he had to spend to make it pass the cities current building code.

Most of the zoning laws and building codes are meant to protect the cities from having a McDonalds in the middle of a residential area or having someone build a structure that is unsound or a fire trap.

I would go the legal route and find out what is possible BEFORE you spend any money on redoing the building.

There was a store front merchant in our town that wanted to make his store's bathroom bigger for his client's comfort and wound up having to spend big $$$$$$ to provide handicapped access and bring his current bathrooms up to code. He would have been OK with what he had because it was "grandfathered" into his lease but once he wanted to make the space larger he was no longer "grandfathered" and had to bring the space up to the current codes. You may run into the same thing.

Doing this illegally is not a good idea but doing it legally may cost you some amount of capital.

One of my good friends ran into a different problem that you may encounter as well. He bought a home in an area that was a combination of residential and commercial. He took an outbuilding on his property and with the proper permits and with the proper architectural plans built himself a beautiful studio complex. No problems with the city and he was ready to open the studio. His next door neighbor got wind of what he was doing and went down to city hall (he was a good friend of the mayors) and complained that he did not want a "recording" studio next to his house. He sited the increase noise level, the traffic and the possible drug sales/use that he said would accompany a recording studio in the neighborhood. He also contacted other neighbors and they too went to the city to complain about the "problems" even though none had happened yet. This was all after the fact and my friend already had spent $50,000 on building the studio. The neighbors then called the police on a daily basis and would report every supposed infraction to them. Having the police at his studio on a daily basis checking on possible "drug use" or noise pollution and having his neighbors at every city council meeting complaining about the noise and the traffic (which was zero because he had not opened his studio) soon persuaded my friend that this was not going to work and he had to move to a different part of town that was zoned commercial.

I would do some serious preplanning and some talking to lots of people BEFORE I decided to do what you are proposing.

MTCW and FWIW

Thanks guys. I just looked up some stuff online, whew. They sure crack heads on that stuff around here. Just this alone made me laugh:

The basics to get a Building permit, you must have with you:

1. The correct address where the work is being done.

2. The contractor's name, address, telephone.

3. The owner's name, address, telephone.

4. Know the work you will be performing and the contract value.

5. Any sketches/drawings needed of the work performed.

6. The fee for the permit.

7. If you are not the bonafide homeowner living on the premises, you must be a licensed contractor.

8. If you are a commercial contractor doing commercial work, plans must first be approved before a permit can be obtained.

9. A zoning permit already obtained if it applies to the work being performed.

Little bit too much stuff for me.