Hoping To Build An Apartment Over The Garage...Any Advice??

[BenH]

Hello Mustachians!

I'm a big MMM fan and am looking for some advice. I don't know anything about architecture or building, and was thinking this community might be a good place to ask?

Anyway, my parents are hoping to build an apartment on top of their detached garage. I love reading about MMM building his own house, making a fancy shower for little cost, and using a heated floors to heat his house.

Do you guys have any cool ideas for the apartment that would make it cheaper to build or cheaper to maintain/heat/etc? My folks are thinking it will cost around $40-50k, but do you think they could potentially do it for less? The garage already has electrical but needs to sewer to be connected. It is a 400 square foot garage and its foundation is decent but needs a bit more added for it to comply with building codes. No one in my family is handy enough to build an apartment, but we might be able to help with easier tasks or learn about more complex ones and then help with them?

Any advice or ideas are very appreciated!

Thank you,
Ben

[MikeBear]

Check with your county first, to see if it's even allowed per zoning. If so, next stop I would suggest getting a structural engineer involved. Not every garage can handle the added weight of a second floor, much less living quarters. You don't want to just "wing it" and build one that'll collapse.

If you don't get the very basics correct from the start, it'll be far more expensive to correct problems later.

[BenH]

Hey Mike,

Thanks for the input! I thiiiink I have that stuff covered, but I'm not 100% certain. I live in Seattle, and we are allowed a mother in law type building in our backyards, so I believe it is legal to build. My girlfriend's dad who is a site superintendent came over and took pictures to send to his friend who is a structural engineer, and he said the foundation could be good to go for like $5k.

I am posting here just to see if any Mustachians who are passionate about houses/tiny houses/frugal building have any cool ideas for the potential apartment. Or maybe there is a Seattle-area Mustachian architect who my folks could hire?

Would love to hear any more thoughts/ideas y'all have!

[Kriegsspiel]

What are the thoughts for building a studio apartment on top of a garage? Seems pretty simple... one room + a bathroom, with hardwood, a range/fridge, drywall, and that's it.  Seems like a pretty low cost way to put a studio on top of a 2 car garage? Has anyone done it before?

[Christiana]

You may want to check out http://ana-white.com on building the "Momplex".  They built most of their own cabinetry.

I lived in an apartment above a detached garage once--it wasn't bad, except for the landlord opening the garage door and starting up his van with the noisy exhaust at 6 am every weekday.  It had outside stairs up to a small deck outside a sliding door, so there was a fair amount of natural light.  No dishwasher, but the kitchen sink was at a window, which made dishwashing more pleasant.  The kitchen layout was a small U-shape, but without the bottom of the U, if that makes sense:  sink and cabinets on one side, and on the other side stove and refrigerator with a small amount of counter space between.  The bathroom didn't have a tub, just a shower.  The furnace and water heater were downstairs in the garage.  It had a barn-style roof with windows only at the two ends, which helped keep the heating costs down.  (Rooms with windows on at least two sides are much more livable.)

For 400 square feet, I suggest really working on optimizing the layout and the storage space:  "cozy" instead of "cramped".  Also remember that someone is going to be moving furniture and appliances in and out of there; don't make the stairs or door impossibly narrow.

[MayDay]

Carriage Houses, as they are called in my town, are very interesting to me.  It seems like its easy enough to get electricity in, and of course you have to have sewer.  What I have pondered is if its worth getting natural gas in, and having a separate furnace, or if you should do some electric baseboard heaters.  Seems like electric heat would cost more monthly, but putting in gas and a furnace might be quite extremely expensive up front.  I would assume you would do a window A/C or better yet a wall A/C (like a window, but installed into a wall, so it isn't blocking your window) since it is only one room. 

[iris lily]

Carriage Houses, as they are called in my town, are very interesting to me.  It seems like its easy enough to get electricity in, and of course you have to have sewer.  What I have pondered is if its worth getting natural gas in, and having a separate furnace, or if you should do some electric baseboard heaters.  Seems like electric heat would cost more monthly, but putting in gas and a furnace might be quite extremely expensive up front.  I would assume you would do a window A/C or better yet a wall A/C (like a window, but installed into a wall, so it isn't blocking your window) since it is only one room.

Plumbing is far more costly than gas lines.  That said, electric heat may be the way to go, depending on your part of the country and winter weather.

[Greg]

You'll have to get the plans engineered to make sure the bottom floor can support the top floor.  It's easy to add studs in the lower level, but the single story foundation might not be up to the task, especially if it's old enough to not contain rebar.

I do design/build in Olympia and am currently adding a second floor to part of a client's house, my engineer designed in some impressive first floor hold downs and shear transfer straps etc. to make it work on a standard single-story foundation.

400 sq.ft. is pretty cozy, I have a 600 sq.ft. studio over my garage and it's cozy for two.  Cost $20K to build the garage/studio DIY with some salvaged materials.  It's heated with a propane-fired wall heater, direct vent, standing pilot.  The water heater is a battery-ignition propane AquaStar on-demand and so work when the power's out, like last night.

One thing to do for making it more efficient is lots of air sealing and lots of insulation. Look up the insulation requirements for Energy Star homes and you'll see what I mean.

The Energy Code is available here:
http://energy.wsu.edu/BuildingEfficiency/EnergyCode.aspx

And if you do the worksheets you'll see what the tradeoffs are for different ways to meet the energy code. 

There are things you can do even if you're not handy, like pull wires and install insulation.  Not glamorous.

[The Architect]

I'd say there are pretty good odds your foundation & garage walls aren't up to the load. BUT - garages are relatively cheap to build, so you might be best off demolishing the old garage and building a new one engineered to have a unit above it. Get a professional involved.

You'll want good energy efficiency and soundproofing.

[FarmerPete]

For heating and cooling, I'd look at getting a mini-split system.  They are 2-3x more efficient than an electric resistance heat source.  They also do heat and AC so you get two for one.  They will cost a bit more than an electric radiator, but they'll pay for themselves over time.

[BenH]

Thank you all for the responses! An architect is coming by the house tomorrow so I'll be curious as to what he has to say!

[Penny Lane]

Do you have a Habitat for Humanity Restore in your area?  These are fabulous for lots of salvaged items-- sinks, stoves, furniture, hardware, some building materials.  We've got old beadboard from ours for the extra bath.  Also, if you have stuff to tear out, they can remove what will sell for you.  The $ goes to a Habitat build.  Win-win-win.