Adding room above garage

[sequoia]

We kinda outgrow our house, and been thinking about adding a room above the garage for storage purpose. The garage is 20 x 20 ft, so I am hoping for extra ~400 sq ft. I am thinking of something similar to this http://www.simplyadditions.com/Stories/The-Master-Suite-Addition-that-Completed-the-Dream.html. But we are not adding anything except an empty room, a light, and couple electric outlet.

If this is not possible, the other option is to sell this house and buy a larger one, but that would be more expensive and more hassle. We are in a great school district and not many house is for sale around here.

To save money, I think I can do the drywall and ceiling, plus the insulation. The rest will be contracted out. I am pretty handy. Anything else that is low hanging fruit that a DIY can do to save some money? I am thinking I can install the carpet myself too - have not decide if we want carpet, or hardwood.

If anyone has done something similar, I welcome any inputs.

[sokoloff]

First thing is to understand the zoning restrictions (if any) that apply. In my city, living space above a detached garage is a complete no-go. "Storage" space above it is OK, provided the total height above the ground plane is no more than 15 feet. Your AHJ is almost surely going to have some kind of rules, mostly around the fire risk and means of egress required that comes from being over a garage if the space is anything other than dead storage.

Next step is to understand the roof/ceiling trusses on the existing structure and figure out if you need to make changes there. Modern trusses (fabricated off-site, to-spec, and delivered to order) is the way to go (IMO) if you need a large clear-span in the garage and a known capacity for load-bearing on the upstairs floor.

But it all starts with the zoning/building department.

[Miss Piggy]

If you're adding storage space for stuff that's just going to be stored most of the time, do you really need the stuff? Can you get rid of a lot of the stuff and eliminate the need for the storage space?

All over my neighborhood, I see two-car garages that no cars will fit in because they are full of stuff. Stuff that probably hasn't been touched in 20 years. I'd hate for that to become your situation.

[Fishindude]

Stuff that gets stored in attics or upstairs storage spaces like that should probably just be disposed of.

[sequoia]

First thing is to understand the zoning restrictions (if any) that apply. In my city, living space above a detached garage is a complete no-go. "Storage" space above it is OK, provided the total height above the ground plane is no more than 15 feet. Your AHJ is almost surely going to have some kind of rules, mostly around the fire risk and means of egress required that comes from being over a garage if the space is anything other than dead storage.

Next step is to understand the roof/ceiling trusses on the existing structure and figure out if you need to make changes there. Modern trusses (fabricated off-site, to-spec, and delivered to order) is the way to go (IMO) if you need a large clear-span in the garage and a known capacity for load-bearing on the upstairs floor.

But it all starts with the zoning/building department.

Thank you - I did not think of zoning/building dept. I am going to check this first.

[sequoia]

Stuff that gets stored in attics or upstairs storage spaces like that should probably just be disposed of.

If you're adding storage space for stuff that's just going to be stored most of the time, do you really need the stuff? Can you get rid of a lot of the stuff and eliminate the need for the storage space?

All over my neighborhood, I see two-car garages that no cars will fit in because they are full of stuff. Stuff that probably hasn't been touched in 20 years. I'd hate for that to become your situation.

My wife sells stuff online, so we are not talking about storing unused junk :)

I agree with what you said, and I have 2 car garage, and both of our cars are parked in it.

[zolotiyeruki]

Ah, at first I thought you just wanted to finish the attic over the garage, but now I see you want to add a second story over the garage.  Big difference! :)

Running electrical is really not a big deal, and very DIY-able.  You'll want to get the beam manufacturer to spec out your floor joists, since 20' spans are nothing to sniff at.  As it's conditioned space, you'll probably also need to run at least one supply duct and return duct to the space as well.

[TomTX]

If you're adding storage space for stuff that's just going to be stored most of the time, do you really need the stuff? Can you get rid of a lot of the stuff and eliminate the need for the storage space?

All over my neighborhood, I see two-car garages that no cars will fit in because they are full of stuff. Stuff that probably hasn't been touched in 20 years. I'd hate for that to become your situation.

My two car garage will fit one car! :D

Admittedly it's a rather small 2 car garage, and the car in question is a Ford Crown Victoria. And we have junk. And good stuff intermixed with the junk. And a wife who won't let me be the determiner of which is junk and which is good stuff that we actually need.

[sequoia]

Ah, at first I thought you just wanted to finish the attic over the garage, but now I see you want to add a second story over the garage.  Big difference! :)

Running electrical is really not a big deal, and very DIY-able.  You'll want to get the beam manufacturer to spec out your floor joists, since 20' spans are nothing to sniff at.  As it's conditioned space, you'll probably also need to run at least one supply duct and return duct to the space as well.

Correct - adding second story - a room above the garage. I guess I was not clear enough in my description. I called the local zoning office, and they said it is ok. I just need to find some bids. I called several places, but so far all of them seems to want to expand the house on the first floor, and that is not an option.

[Smokystache]

Just curious if you've had an update on this. I'm considering adding a workspace above a garage. just like you I would need to raise the roof of the garage to create enough space to make it worthwhile. (This space would be to allow me to keep my side business at home and not need to rent commercial space or storage).

It seems like it "should" be one of the cheapest ways to add space ... assuming the garage was mostly built to support a second floor. I'm not looking at adding a bathroom/sink - so I don't need to worry about water/sewer.

[bacchi]

It seems like it "should" be one of the cheapest ways to add space ... assuming the garage was mostly built to support a second floor. I'm not looking at adding a bathroom/sink - so I don't need to worry about water/sewer.

That's probably the 2nd most important question, after zoning and deed restrictions.

Does the garage have the studs that can support a 2nd floor and roof (+ snow?) load?

[paddedhat]

It's a pretty good bet in most post war era US homes that the garage will have 2x4 walls on 16" centers, as a minimum, if there is adequate sheathing (plywood, chipboard or diagonal board ) it will satisfy most locations without seismic concerns. In my region, a lot of local inspectors will make you excavate a small area of the supporting foundation wall and footer to gauge if the existing is adequate to add more load to. Since a lot of foundations predate current code requirements, this leads to a lot of unhappy homeowners, since many builders would cut corners with shallow undersized footers, and walls that were too short to provide frost protection. Nothing to find 3-4 courses of block on top of a 4" thick footer in my area, when six courses and an 8" thick footer is what the inspector needs to see.  Bottom line is, once you you know that it's legal to proceed, for many the next step is a shovel to find out if the  original structure is built on a foundation worthy of a second floor.

[Smokystache]

I'm leaning against this idea now - not because I don't think it would be a good way to add sq ft to my home, but b/c I don't think I was looking at ways to maximize my current space.

But I should have mentioned that this garage is connected to my house and has a small attic space (too small to be able to finish the current attic space and have it be worth it or meet my needs).

This is similar to my setup:

[Sherriscott]

Great idea. Storage room above garage I like it. It will be great to keep some of the things which are not in use. I will surely think on this.

[paddedhat]

When it comes to a need for pure storage space don't forget that, if the lot size, and local regs. allow, a pre-built shed is exponentially cheaper that building second floors on garages, or other additions. Taxes are cheaper, and the thing can be removed if circumstances change. Not that I'm advocating more space to store needless consumer shit, but if you need a place for inventory, or even a quiet getaway from the house to do office work, there are some amazing options available. It seems that I live at ground zero when it comes to Amish shed building, and it's amazing to see what's available in great looking, solid portable buildings in this area.

[sequoia]

Just curious if you've had an update on this. I'm considering adding a workspace above a garage. just like you I would need to raise the roof of the garage to create enough space to make it worthwhile. (This space would be to allow me to keep my side business at home and not need to rent commercial space or storage).

It seems like it "should" be one of the cheapest ways to add space ... assuming the garage was mostly built to support a second floor. I'm not looking at adding a bathroom/sink - so I don't need to worry about water/sewer.

No I do not have any update. I have contacted several contractors, everyone wants to build on first floor which is not an option since our land is small. We also can not add additional storage or shed, otherwise this would be the way to go. One guy even come and measure here and there, but never to be heard again. It is very frustrating.  Our only option is adding this room, or move to a larger house.