Building a Semi-submerged Garage

[tuscani451]

Hello GJ, we are looking to move to a new home (staying in east valley Phoenix). I really wanted a 3 car garage this time to work on my various race bikes, unfortunately this pushes the average cost rather high. I can get a large lot and could add a separate structure however if there is an HOA it would have to below the fence line. I was thinking I could build a garage (that could later be converted to a guest house) with the floor 4 feet below the surface thus keeping the roof below your average 6 foot block wall. Bad idea or mad genius?

-Leif

 

[C_F]

One bad scenario comes to mind...on the rare occasion that you get a ton of rain, the inside of your garage might be 4' deep in water.

 

[no704]

Could u get a varriance ?

 

[tarmy]

Probably no insurance for the structure either...nor contents. Also, no insurance equals no loan. The bank will want their money protected.

 

[bad_idea]

<---- See screen name.

 

[Orionrising]

semi submerged may be the result... it think the word you wanted was subterranean.

 

[matt_i]

As said, I think bad idea in monsoon season rains. The ground doesn't absorb water fast enough and so it concentrates in low areas....hence the "washes" in the desert filling up with enough water to wash away cars.

 

[yhprum]

It could work... on a bonus it might stay cooler. Do you live in on high or low ground? Its really no different than a basement is it?

 

[jives]

It really depends on the geography and geology of the land. Basement garages with steep downsloping driveways can be done as long as drainage is done right. Your idea seem akin to a split ranch, which I'm sure exit in AZ. There is also the option of a "berm house" type of structure.

In AZ I cannot think of a better idea than a bermed structure.

 

[glentre]

Not a bad idea at all and certainly doable under the right conditions. Site location is important and strict attention paid to drainage control and waterproofing the walls. Difficult and expensive to do if you are in a low area or where there is a high water table....easier if you are on the top of a knoll. I would urge you to evaluate the idea further and get some professional help if you need to.

Glen

 

[tonyciambrone]

On my old street there are three split level houses with the garage below grade. We all get to waive to each other every time it rains hard... garage doors dont hold water very well once the city drains fill up, or your float switch dies, or your breaker pops, or something gets lodged in your sump pump, etc etc.

It's just begging for problems in my opinion. One of the main reasons I bought a different house...

 

[rsanter]

Why now just design the house with the shop as part of it so there are no separate rules for height and such.
I saw where a guy wanted a big garage but there was a limit on garage size. So he added a special mulitpurpose room onto the house what happened to be 6 car sized. There were large double opening French doors to the back area.
The room was specified as a multi purpose family/play room.
Passed no problem, he then parked his cars in there

A friend of mine wanted a separate woodworking garage. HOA said no there is a limit to garage size. So he built an Art Studio, which passed.
He does woodworking in it

 

[kbs2244]

Is the rule for detached only?
Check out what 3 car attached would cost.

Or, as said, build a "Hobby Shop"
Small, single car, door might be wise.

 

[ard]

IMO 'bad idea'...

assuming this is an established neighborhood in a flat desert environment, a building that is 4 feet deep to access will be an oddity.

Also, I have NEVER heard of an HOA in which the singular criteria for all secondary building is 'cannot be above the fence'. Is this one specific HOA? Are you sure? or is this a realtor telling you?

 

[no704]

Tempe resident, bout twice a year the streets are flooded out. This would be a bad plan.

 

[e015475]

Keep looking for a another house with a three car garage.

In the Phoenix area a garage is worth about $8-10K, which works out to about $20 a square foot. You can't build anything for $20 a foot and you can finance the garage in the mortgage. I would imagine the excavation/grading alone costing $8-10K for your subterranean space, assuming no rock or caliche.

Setting aside the flooding potential issues for the moment, I'd talk to an appraiser first. This looks like an opportunity to spend a wad of money and, best case, get little or nothing for it at resale.

I believe to be considered livable area, the space has to be at the same grade as the house. I question the viability of converting it into a guesthouse at a later date. Even if you could, I think a guest house whose roof line was 6' above grade would be a white elephant at resale.

If you're committed to a stand-alone structure, a better idea might be to get an approval for a guest house up front, but design it such that you could use it for your motorcycle hobby now and convert the interior to livable space when you want to sell the property. But even if you're successful with this, guest houses typically on get 50% of the square foot price of the house.

PS - the OP's comments about the HOA and limiting the height to 6': HOA's typically don't require approval of structures that can't be seen in the backyard. If you go over 6' you'd likely need to get HOA approval (if there is one)

 

[Aberdale]

Why now just design the house with the shop as part of it so there are no separate rules for height and such.
I saw where a guy wanted a big garage but there was a limit on garage size. So he added a special mulitpurpose room onto the house what happened to be 6 car sized. There were large double opening French doors to the back area.
The room was specified as a multi purpose family/play room.
Passed no problem, he then parked his cars in there

A friend of mine wanted a separate woodworking garage. HOA said no there is a limit to garage size. So he built an Art Studio, which passed.
He does woodworking in it

I like this idea. It would be great to have the cars and motorcycles in the house. It might be difficult to get homeowners insurance. Those pesky insurance companies hate things that are a little different.

 

[Angelfire]

Make your fence taller!

Seriously though, this could work just fine depending on your lot. If at the top of a hill anyway, drainage would be in your favor. If flat, I think you'll have other challenges considering your driveway would essentially be dug out below grade. Not much rain in Phx, but when it does rain, you get a lot in a very short time (same is true here in ABQ) which I think would be problematic.

 

[d300]

...move out of town and get a couple of acres. Problem solved.

 

[rattle_snake]

Keep looking for a place that has something already. easiest will be a regular home with 3 car. Places with detached shop in phx area are few and far between.

Plan B is a county island with no HOA (or city BS for that matter) and build whatever ($$$).

 

[tuscani451]

Thank you for your input everyone, I am constantly blown away by the depth of knowledge here!

As noted drainage would have to be spot on, AZ obviously doesn't get a ton of rain but when it rains it pours so to speak. The land here doesn't absorb water very readily due to the caliche which also makes building below ground a challenge-one reason very few homes here have basements. That being said the natural cooling effect of having the house below ground is very appealing.

I can see if a variance would be possible, some HOAs are better than others. My current HOA is very specific about structure above the roof line but it's possible others wont be as bad.

obviously buying a house with a 3 car would be ideal but we are trying to move in closer to central Phoenix so new builds are not an option and most areas are long established. The garage itself doesn't add to the cost but neighborhoods with 3-car option in general have a higher price. I do think adding a guesthouse that I could use as a workshop would add a lot of value down the road.

 

[bczygan]

We call them boats.

 

[ard]

I do think adding a guesthouse that I could use as a workshop would add a lot of value down the road.

I agree with that sentence.

BUT

You really need to get a handle on building costs... IMO a structure that COULD be turned into a living space will NOT have the same costs as one of these outbuilding garages/sheds we see posted here. You can be well over $100k for a shell that matches the home (with the appropriate engineering and utilities to one day convert). Such a building may indeed 'add to the value'...but a ramshackle, half submerged building that looks like a shed may not add the value you think. When you add up the actual costs to build a matching secondary structure that adds value, you may be at that pricing difference you see in the market.

GL