another tip about hiring the architect:
Hire one who has lots of experience in your very specific location.
If your urban area is spread over more than one municipal boundary, make sure your architect has personal experience with the engineering dept of your location.
Dealing with the bureaucracy is a huge headache, and every city is different.
If your architect claims “experience”—because he has built many houses 15 miles away from you, but across the county line under a different jurisdiction-- don’t consider him experienced for your needs.
Not just the architect, but the contractors as well.
When we’ve planned work, we have gone into the village/city hall, and said, “Which fencers/contractors/etc do you work with all the time and have NO problems with?” Makes the whole process go a lot easier. One neighbor - who always prides themselves on shopping for the lowest prices - consistently had non-name or unfamiliar to me contractor vehicles during several projects. Each of them took WAY longer than they ought to have, with lengthy periods of inactivity. (Speaking as someone who recently had his entire house essentially rebuilt, inside and out.)
What’s the ballpark figure for something like this? 20k? 50k? 100k? It’s something I’m like to do someday, too, I just don’t know if that someday is likely to be 10 years or 50 years from now
An alternative approach you might consider is to just tear down the existing garage and build a new structure.
floors have nothing to do with load bearing walls. They float independently of them.
As for those who think you need an architect that depends on the skill of the homeowner and how crazy the codes are. The city should provide all the requirements for construction. It’s not rocket science. If they say they need 2x6 boards 16" on center then that’s what you build. Once I had their requirements I was able to draw up basic construction plans.
I rebuilt my garage and extended it quite a bit. I even got some variances on size restrictions. The only problem I ran into was wiring. I specifically asked what underground wire they would approve and then ran it inside buried conduit. The inspector balked at the type of wire but passed it because it was in conduit. I should have gotten everything in writing before I started. Also ran into a bit of a problem with bracing. Instead of a 2x4 cross brace on the corners I spanned the whole thing with sheeting on the trusses which was structurally more secure. the inspector agreed and approved it. I’m not an engineer. All I used was common sense.
If you don’t have mechanical drawing skills then an architect will simplify the planning process. If you have basic plumbing, roofing and construction skills then there’s no reason why you can’t build it yourself. If you don’t have those skills then you have an uphill battle. the biggest regret I had was the foundation. I had it dug out ready to go. Before I could get it inspected it rained so hard it collapsed part of it. It took longer to redo it then the original work. Lesson learned.
A final thought, it’s possible to have the codes change on you during the project. Had that happen to a friend of mine. The city upgraded their codes on electrical outlets so we had to be replace all of them. Grrrrr. Once a permit is issued it should grandfather the original plan (within a set time limit).
But wouldn’t the footings/foundation beneath the slab for a single-story garage be less substantial than those for a 2-story structure?
Just to clarify there are no national building codes each state adopts their own building and fire code. In most cases, the cates codes are based on the International Building and Fire Code but each state uses a different version in the sense that one may use 2016 but another 2012. In some cases like California, they have made enough changes to the IBC that they call it the CBC (California Building code). On the other end of the spectrum there is Missouri where there is no state building code and so in most unincorporated parts of the state, you can do whatever you want. All that being said there are also going to be municipal adoptions of building codes that may or may not be different than the state code. For example, Colorado uses the 2012 IBC as their approved code but the City of Denver has added the Denver Building Code Amendments on top of that. Figuring out what the rules are for your location is generally just a call to your local regulators who will tell you who’s in charge and what their rules are.
I don’t deal much with home construction since my focus is on commercial and industrial engineering but I work for an architecture firm.
Architects have value for a couple of reasons they are specialists in interpreting the code, they can bring together multiple specialties and work as a nice pivot point to the design team, and they tend to focus more on things looking nice than engineers. That being said if you’re good at reading laws the code isn’t that hard to read but there are lots of exceptions and workarounds so it’s not exactly straightforward and we spent a lot of our time teaching building officials about what their code actually says. For something as simple as a garage you’ll basically have a mechanical engineer, electrical engineer and maybe a structural engineer but the arch could probably replace the structural. Pretty is in the eye of the beholder but if you’re going to go for a whole new roof line I’d definitely bring in an arch.
All of that being said there are lots of jurisdictions that will allow contractors to do the design as long as they also build it (California) and residential projects are held to a lower standard than commercial or industrial construction so in some places inspections aren’t required and a permit is a one page applications saying you’re going to build a room over the garage. I’d start with a local Arch since they’ll know this stuff and will be able to move you through the quickest. A Civil/GC can do the same thing too and it may even be more constructable though possibly less pretty.
What are you talking about? Your statement implies you could build a skyscraper on top of a garage slab. No, if you add a second floor (floor = story) to a garage, you will need to beef up the foundation unless it was originally built to hold a second story.
The OP has made it clear that he’s not a DIYer.
No, that’s not correct. Once you have your building permit, you go by the code that was in place when the permit was issued. In fact, you should be able to do so based on the date you submitted the plans, not the date the permit was issued.
If someone did that to your friend, it was due to an over-zealous inspector and he or she should have been challenged. Municipalities often get flooded with plans at the end of the year in order to lock in the existing code before it changes.
Did I? Hm. I mean, I don’t do foundations or framing but the rest (siding, roofing, wiring, plumbing, drywall, tile, etc.) is not a big deal. I just have the day-job and come home to 3-5 chaotic neutral teenage boys. I don’t always have time to finish projects as quickly as The Missus would like. And…and my finish carpentry is shit.
It would be of great value (both to them and to you) for these kids to participate in this construction project.
When people see your finish carpentry, you’re finished? 
I took your statement, above, to mean that you were not going to DIY on this project, and I didn’t mean to imply you couldn’t do those things. Sorry about that. But still, if you haven’t done something like tile before, you don’t want your first attempt to be on your own bathroom.
Further to the code change thing, perhaps what happened is that the plans were submitted and whoever did the plan check did not catch a code violation. If the inspector calls you on something like that, you do have to comply. You can’t just say “but the plans were approved like that”. I’ve seen that happen more than once.
No my statement doesn’t imply that. The foundation for the World trade center is relative to the weight it has to support which is millions of lbs. The weight on a 2 story building is nominal in comparison to a single story building because the foundation has to be deep enough to accommodate the frost line and that is going to be much greater than the compression load of a 1 story foundation. The floor of a standard garage is independent of the foundation and does not carry the load of the structure. It’s designed to float independently of the foundation.
Not really. If we’re talking about a cement foundation then it’s purpose is to form a stable platform below the frost line. Whether it’s 3 feet or 6 feet deep is a function of the frost line. It has to be below this to be stable. If it’s not below the frost line then the freezing and thawing of the ground will heave it up and down. But as far as a support for a 1 or 2 story building it doesn’t need to be nearly that thick to support the weight above it. It’s concrete. In compression strength it’s pretty substantial.
Thanks for this! We are currently finishing up plans to build out the attic and just starting to talk to contractors, and this will be very handy advice.
It sounds like you have a handle on the situation. Chef Guys suggestions are spot on about managing the project. From a financial POV you have a lot of options between doing it yourself and letting someone else handle all of it. You can mix any combination of outside help and your own labor to save money and get it done to code. I’m also a fan of over engineering stuff so I like to build to a greater standard.
I would add that you already appear to have the skill-sets needed to inspect the work in progress. You would be surprised how easy it is to spot something wrong before it gets out of hand. I was at a friend’s house years ago while a plumber installed an outdoor faucet. I watched him for a brief moment and I thought he was a bit generous with the torch. He finished and left and we were heading out ourselves. On a cautious whim I felt the interior wall opposite the outside faucet. Yep, it was warm. he set the studs behind the exterior brick wall on fire. So we had to cut a hole in the wall to put it out.
Some States have construction contractor licensing programs that are fairly exhaustive, like California … some States don’t have any at all, like Pennsylvania …
Two things you should demand of your contractor … Liability Insurance; if the contractor drops a sheet of plywood on your neighbor, then his insurance company pays the hospital bill, not you … Performance Bond; If the contractor does shitty work, the bonding company pays to have it fixed, not you …
Both are absolutely critical to protect your own financial resources … insist on the documentation, or tear up the bid proposal …
Unless the local authorities require something else you only need a residential contractor. You’re not Randolph Hearst adding a room on a garage at San Simeon, you don’t need an architect. You won’t need an engineer unless the construction details of the original structure are unknown. The contractor will know the local codes and be able to determine whether existing walls and foundation need to be modified.
Someone will have to draw up the structural plans. You don’t have to be a licensed engineer to do that, but you have to know how to do it. Most contractors wouldn’t know how to, and while most architects probably could handle it, my experience is they prefer not to. It’s going to be depend on the architect/designer.
You don’t need to be an architect to draw up the architectural plans, but you need to be familiar with the all the building code issues as most municipalities will want them listed explicitly on the plans.
Submitting a bunch of half-assed, incomplete plans is good way to delay the whole permitting process.
Remember, contrasting styles add interest.
Most contractors have software for all of this and the local authorities will hold them to a standard suitable for the project.
Some contractors might have CAD programs that they use, but few really know how to use them. It’s going to be more common in big commercial firms, but small residential contractors that do garage additions? Rare.
Anyway, you don’t just push a button in a CAD program to spit out structural plans. Engineers are going to have all sorts of boilerplate details that they cut and paste into all their plans, but you still have to draw up the plans, and you have to know what you’re doing to do it right. I work with these guys all the time, and I know I couldn’t do it.