discussion on adding 2nd story above garage

[mound]

We've have an 1800 sq/ft colonial, two stories with attached garage. The garage portion is one story with a family room behind it. The single-story side of the house with the garage+family room is on a slab. This side of the house has a gable roof. 

We've begun considering building out a 2nd story above the garage/family room for a master bedroom/bath. The garage is currently my woodworking shop.

Clearly a project for a professional builder to spec out and quote, but I'm curious to hear thoughts, general discussion, horror stories etc about what sorts of questions and gotchas can arise when exploring a project like this.

[Cooler]

We've have an 1800 sq/ft colonial, two stories with attached garage. The garage portion is one story with a family room behind it. The single-story side of the house with the garage+family room is on a slab. This side of the house has a gable roof. 

We've begun considering building out a 2nd story above the garage/family room for a master bedroom/bath. The garage is currently my woodworking shop.

Clearly a project for a professional builder to spec out and quote, but I'm curious to hear thoughts, general discussion, horror stories etc about what sorts of questions and gotchas can arise when exploring a project like this.

In a word:  Architect.

Two of my neighbors made major additions on their homes.  One was designed by the home improvement contractor and one was designed by an architect.  You only need your two eyes to see which is which.   The interiors are both nice; the exteriors are a world apart.  

Find a local architect whose work you like and have him design the addition.  Then take that design around and get several bids on the same project.  You will probably save more than the architect's fee by having plans that allow you to shop.

I would also note that my parents lived in a split level home.  When they were in their late 70's all the stair climbing became a burden.  So if you can have your master bedroom, kitchen, and a bathroom all on the main floor you will not have to do all that climbing.  A lot depends upon your age now and how long you plan on living in this house.

[Robert Adams]

That's a bigger project that most might think. Assuming the slab is capable of to load the walls will also have to be capable of the load then you will put in lots of floor joists as the ceiling joists are not adequate. Then go up from there. 
      Building up is cheap in new construction but in a remodel it's very expensive. If it were me I would build out not up. If that wasn't possible and I really needed the space I would be looking at houses and prepping mine for sale. Get a few quotes and you will find its cheaper to sell and buy more space than to add a floor.

[Snipe Hunter]

That's a bigger project that most might think. Assuming the slab is capable of to load the walls will also have to be capable of the load then you will put in lots of floor joists as the ceiling joists are not adequate. Then go up from there. 
      Building up is cheap in new construction but in a remodel it's very expensive. If it were me I would build out not up. If that wasn't possible and I really needed the space I would be looking at houses and prepping mine for sale. Get a few quotes and you will find its cheaper to sell and buy more space than to add a floor.

If the garage has walls, it should also have a foundation with the same requirements as the rest of the house. The slab should have been poured within the foundation. I wouldn't see why the foundation holding up the garage would be any different than any other load bearing foundation. But that would be on the drawings at the county.

Most decent builders/remodlers have an architect they use so I wouldn't start there. I'm thinking the owner could save a few bucks. I'm guessing that the addition is pretty much cookie cutter aside from the master bath.

Plan on re-siding everything and a new roof if the addition is a continuation of the existing roofline

[jasfrank]

No mention of how it's currently constructed, but if the garage has standard type trusses, you would be looking at a complete new roof structure. It's not a huge trick to run I joists across for a floor, but something has to support the roof.

[mound]

thanks for the comments.. all good stuff!

[Ken Vick]

thanks for the comments.. all good stuff!

Of course, the cross sectional measurements of a footer are different for a one story structure as opposed to a 2-story structure.  The footer under the garage part of the current house is likely not big enough to support a 2-story structure.  Even though the footer of the garage and house are connected, don't count on someone spending the extra money to beef up the garage footer in case someone wanted to add a second story.  Ken

[mound]

Was chatting with a neighbor who has the same model house as mine and he did exactly the type of expansion I'm thinking of. He should be a good resource. He said no changes were required to his foundation

[srv52761]

Was chatting with a neighbor who has the same model house as mine and he did exactly the type of expansion I'm thinking of. He should be a good resource. He said no changes were required to his foundation

That may help.

But verify. If you can locate the blueprints check the specs. Still, having a reputable professional help is still the way to go if you decide to do the work.

I moved just one lally column in my basement to make room for a pool table and had to have an architect spec the mod for insurance purposes (we still had a significant portion of our mortgage so technically the bank still owned the house, I guess). But it was best money we spent in all our remodels.

[mound]

 That may help.

But verify.  If you can locate the blueprints check the specs.  Still, having a reputable professional help is still the way to go if you decide to do the work.

I moved just one lally column in my basement to make room for a pool table and had to have an architect spec the mod for insurance purposes (we still had a significant portion of our mortgage so technically the bank still owned the house, I guess).  But it was best money we spent in all our remodels.

No doubt. This isn't something I'd even consider doing myself.. I figure if they can do the major framing, roof changes, new roof and new siding, rough plumbing, HVAC and electrical, I could do all the finish work.