6-Car Garage Parking Configuration?

[nobbyv]

Hi guys, just joined up to get some opinions and info on my new project. I'm building a new house. For cost purposes, I'd like to keep the garage UNDER the house. I bought some home design layout software and have tried a few different layouts.

Currently, I have the garage at 48'x40' (12' ceilings). I'd like to be able to fit six cars, plus have room for a workbench/tools/etc. There's another bumpout connected to it where there will be a 1/2 bath, so I don't need one of those in this space.

I'm struggling a bit with the best configuration for six cars. I'd love to be able to avoid shuffling all the cars to get the "deepest" one out if possible. With this in mind, I was contemplating putting a 20' door on the long (48') side, and having all six cars parked as in a parking lot: pull straight in, then a 90 degree turn either left or right into an available spot. However, allowing ~18' on each side for the parking spots, this only leaves 12' for the center "aisle". I actually tried this out: I went to a empty parking lot, and brought a few traffic cones with me that I spaced 12' from the front of the spot (the actual aisle was 20'). I was able to pull in, but it was a pretty sharp cut, and I'm concerned that I will get sick of doing this.

This configuration also doesn't tend to leave a lot of room around the cars themselves; too much floor space is eaten up by the center aisle (which is empty 99.999% of the time).

I'm also trying to avoid building the house above unnecessarily large, so simply bumping out the garage foundation isn't an ideal option, either.

What are some other options for six cars? Design a simple three wide by two deep with three doors and resign myself to having to move one car to get at a "deeper" one? I don't like the idea of doors at both ends, either. Is there another configuration I haven't considered?

Thanks!

 

[rjacobs]

4 post drive on lifts... with 12' ceilings you would be fine unless you have stuff like big trucks or what not. But that still entails moving a car to get another one, BUT free's up a ton of space.

 

[nobbyv]

4 post drive on lifts... with 12' ceilings you would be fine unless you have stuff like big trucks or what not. But that still entails moving a car to get another one, BUT free's up a ton of space.

Thanks for the reply.

Yeah, I said 6-car (and that's what I tell me wife), but I always had in the back of my mind that it could easily be an 8-car with a few four-post lifts. But maybe I should consider resigning myself to that: plan floor-level parking for four, and install two lifts.

And no big trucks for me, so lifts would definitely work at 12' ceilings...

 

[astroracer]

I am just thinking out loud here, listen if you want, or don't. Just getting you to think about real world building concerns.
My first concern is 40 x 48 under a house is probably not going to be free span unless this is a no holds barred, devil be damned on the cost, build. Free spanning that 40' is going to take some really tall joists.
Also 40 x 48 is almost 2000 sq. ft. That's getting pretty good sized in my book.
You need to think about costs here. Talk to a builder and get some sq. ft. estimates. You will find it is cheaper to go up then it is to go out.
A 28 x 40 house would still get you a lot of room underneath.
I think you will find it is much more cost effective to build a stand alone shop and keep the house footprint to a manageable size... The shop "per sq. ft." cost should be much less then the house.
Mark

 

[rjacobs]

well 40x48 would be 8 cars stored flat. But like you said you want work shop space so you are really working with like 40x36.

So you have the double deep covered with the 40' and 36' wide is roughly 3 cars wide.

What I would probably do is 2 4 posts lifts along the back wall to store 4 cars, then park 2 cars in front of them. That is roughly call it 40x24 of your space. So you still then have 40x24 of space for work shop, motorcycles, etc...

With the setup I have laid out, moving cars becomes a bit of a pain, but you just have to realistically determine which cars get driven the most and park those in front, then the next 2 most driven, etc...

If you truly drive all 6 cars an equal amount then you are going to need to do something else. My guess is if you sit down and REALLY determine how much you drive the cars, you can figure out a storage solution. I mean if you drive one of your cars 1k miles a year, IMO there is no reason to NOT have it stacked on a 4 post with a car you drive say 4k miles a year under neath it. Then have the daily driver parked behind those 2.

 

[stm317]

I'm with Astroracer. Custom homes can easily be $200/sqft. A separate garage would be much less.
If it all has to be attached to the house, then I'd size the garage based on the house footprint, or make it larger than the house, but then extend it off of one end and cover it with a patio or porch or something.
How did you settle on the 40X48 if you don't have a floorplan for the house that goes above it? It seems kind of arbitrary.

 

[nobbyv]

I'm with Astroracer. Custom homes can easily be $200/sqft. A separate garage would be much less.
If it all has to be attached to the house, then I'd size the garage based on the house footprint, or make it larger than the house, but then extend it off of one end and cover it with a patio or porch or something.
How did you settle on the 40X48 if you don't have a floorplan for the house that goes above it? It seems kind of arbitrary.

Thanks for the replies guy!

I actually DO have a floorplan for the house, and I did just what you mentioned: the house footprint is only 30'x38', with a 10' deep covered farmer's porch wrapping around two sides that sits on the garage foundation. It's a 1.5 story design, and leaves me about 2500 sq ft of living space, which is perfect for us. I guess I was just struggling with making the basement/garage footprint bigger without greatly expanding the finished house square footage, but some sensible deployment of 4-post lifts seems like it would get me what I want, or possibly even let me scale down the basement/garage just a bit.

 

[nobbyv]

I am just thinking out loud here, listen if you want, or don't. Just getting you to think about real world building concerns.

By all means! I've never done this, and any and all input is welcomed.

My first concern is 40 x 48 under a house is probably not going to be free span unless this is a no holds barred, devil be damned on the cost, build. Free spanning that 40' is going to take some really tall joists.

Good point. I always kind of assumed that this would require 1 (or two) steel I-beams like I have in my garage at my current house now (garage is 22'x20'). But I know it's a lot more difficult than just saying "throw an I-beam up there, it'll be fine". A consultation with a structural engineer sooner rather than later would probably be a good idea if I decide to keep the 40'x48' footprint.

 

[GMCGarage]

I am just thinking out loud here, listen if you want, or don't. Just getting you to think about real world building concerns.
My first concern is 40 x 48 under a house is probably not going to be free span unless this is a no holds barred, devil be damned on the cost, build. Free spanning that 40' is going to take some really tall joists.
Also 40 x 48 is almost 2000 sq. ft. That's getting pretty good sized in my book.
You need to think about costs here. Talk to a builder and get some sq. ft. estimates. You will find it is cheaper to go up then it is to go out.
A 28 x 40 house would still get you a lot of room underneath.
I think you will find it is much more cost effective to build a stand alone shop and keep the house footprint to a manageable size... The shop "per sq. ft." cost should be much less then the house.
Mark

Easily spanned with a double Tee, steel beam, or even wood floor trusses.

 

[LX-Markham]

^^^I was thinking coreslab, but double tees are a good idea too.

 

[01-7700]

Easily spanned with a double Tee, steel beam, or even wood floor trusses.

no bouncy bouncy on the first floor?

 

[Voi]

What are some other options for six cars? Design a simple three wide by two deep with three doors and resign myself to having to move one car to get at a "deeper" one? I don't like the idea of doors at both ends, either. Is there another configuration I haven't considered?

Thanks!

We're in the drafting stage for a new house. Our garage will be about 20% smaller than yours. I'm not sure what you mean by "doors at both ends" but we're going to have a small overhead door on one of the gable walls for us to park our UTV behind a smaller car in the third stall.

The main overhead doors for vehicle parking will be on one long eave. So the small overhead door will be perpendicular to the main overhead doors.

Ideally the UTV will end up on a lift but I'll still include that small door.

 

[atch]

Seems like it would be really easy to have a 3-car garage level with the house main floor with a 3-car garage under it.

When I worked home construction during summers in high school (50 years ago) we built garage under garage routinely. We did the framing/forming and concrete pouring as well as all the rest of the carpentry, painting, landscaping, street building, etc. These houses are still standing and doing just fine. I bet with today's technology it would be even easier than what we did. I don't remember all of the specifics but I think we reused all of the forming materials (plywood, 2x4s, 2x6s, etc.) in the actual house construction.

Not criticizing your "all in the basement" plan; just offering alternatives.

 

[evildky]

standard parking spaces in parking lots is 9x17, just an fyi.

I'd have 2 16" wide doors on the 48 side. First door 2-4 ft from side wall that gives you pretty easy parking for 2 wide and 2 deep, then the next 16 door spaced about 4" of the first door, leaves you 8x40 work space.

 

[bkibler]

I have a 6 car garage built into my house: 3 in the basement, and 3 on the first/ground floor above it, with precast concrete joist/floor in between. 8 feet ceilings in the basement part, and 14 feet on the ground floor. It could easily hold 8 or 9 cars if you put lifts in the upper level. I think the clear-span concrete is 28 feet, for 28x40 on each level.

We use the upper level for daily drivers and kids toys, and the lower level is a workshop and race car parking.

The only real downside is that the 8 foot ceiling on the lower level isn't high enough for a proper lift, so I only have a Quick Jack down there. And my wife complains of odors in "her" garage when I'm doing welding projects downstairs.

The whole setup is pretty stealthy, and you'd never guess from the street how much storage I have.

I'll try to scrounge up some pictures...

Sent from my Pixel using Tapatalk

 

[lakeroadster]

We had a 6 car garage at our last home that we used just for cars.....

We left the center front bay empty and you could store 5 cars and not have to move a car to get a car out. No musical chairs...

Here's a photo... the orange truck was usually not in this garage, and the daily drivers were in the front bays, left and right...

 

[bkibler]

Here are some pictures of my over/under garage setup.

View from the street, nothing looks out of the ordinary:

View from the side, just a ground-level 3-car garage:

Once you drive around to the rear of the house, you can see the entrance to the basement garage:

The basement garage is also 28 wide x 40 deep, but it only has a single 8x12 door, and it's mostly workshop and junk storage these days. I can tuck something small like the FFR off to the side as shown here, and still fit 2 other compact cars (or a single F-350 size truck) in the concrete lift area. You can see the 28' concrete span roof in this picture:

During hurricane or tornado season, it's also nice to have part of the house surrounded on all sides by 12+ inches of concrete, including the roof and floor.

 

[firebirdparts]

Easily spanned with a double Tee, steel beam, or even wood floor trusses.

Yikes! The house is actually only 30 feet wide. This will require quite some structure to support on a 40 foot span.

A 40 foot wide house could easily be supported on a 40 foot basement, but that's not what he wants.

 

[bczygan]

Hi guys, just joined up to get some opinions and info on my new project. I'm building a new house. For cost purposes, I'd like to keep the garage UNDER the house. I bought some home design layout software and have tried a few different layouts.

Currently, I have the garage at 48'x40' (12' ceilings). I'd like to be able to fit six cars, plus have room for a workbench/tools/etc. There's another bumpout connected to it where there will be a 1/2 bath, so I don't need one of those in this space.

I'm struggling a bit with the best configuration for six cars. I'd love to be able to avoid shuffling all the cars to get the "deepest" one out if possible. With this in mind, I was contemplating putting a 20' door on the long (48') side, and having all six cars parked as in a parking lot: pull straight in, then a 90 degree turn either left or right into an available spot. However, allowing ~18' on each side for the parking spots, this only leaves 12' for the center "aisle". I actually tried this out: I went to a empty parking lot, and brought a few traffic cones with me that I spaced 12' from the front of the spot (the actual aisle was 20'). I was able to pull in, but it was a pretty sharp cut, and I'm concerned that I will get sick of doing this.

This configuration also doesn't tend to leave a lot of room around the cars themselves; too much floor space is eaten up by the center aisle (which is empty 99.999% of the time).

I'm also trying to avoid building the house above unnecessarily large, so simply bumping out the garage foundation isn't an ideal option, either.

What are some other options for six cars? Design a simple three wide by two deep with three doors and resign myself to having to move one car to get at a "deeper" one? I don't like the idea of doors at both ends, either. Is there another configuration I haven't considered?

Thanks!

What does your lot look like?

Bill

 

[wssix99]

I live in a house built on top of a 30X40. We double stack the cars. I recommend you plan for this, no matter what. You'll want working space and this will afford you some. With 12' ceilings, you'll end up with a ton of wasted volume otherwise.

My first concern is 40 x 48 under a house is probably not going to be free span unless this is a no holds barred, devil be damned on the cost, build. Free spanning that 40' is going to take some really tall joists.

+1. Free span is not going to happen. Even if you are Tony Stark and have the coin for it (and the 2 foot thick floors it would require), you could end up with really bouncy or flexible floors up above, which is not good for a live-in house or floor finishes.

The first step should be to figure out where you columns need to go and how you are going to avoid clashes. In my garage, we needed one - but it went right were we'd be opening car doors. So, to solve for the problem, we upped the columns to two. We ended up with more columns (one at the front of the garage and one at the back) but they are well clear of car doors. etc.

There's another bumpout connected to it where there will be a 1/2 bath, so I don't need one of those in this space.

Some things many folks aren't thinking about at this stage is gas flammability and slab cracking:
- Your garage will be fire-walled off from the rest of the house. This space will need minimal doorways to the rest of the structure. (They are week points for fire resistance.) If you have a bathroom in this protected space, then it would be best to raise it up off the floor with a gas curb. Garages have heavier-than-air gasses in them, which congregate on the floor. (You don't want them in your bathroom.) For this reason, code also requires that you slope the floor towards the garage doors to evacuate these gasses.
- Your garage slab will shrink as it cures. Rectangular shapes are easiest to make and manage the stresses created by this shrinkage, which lead to cracking. "Bump-outs" create features called re-entrant corners, which tend to entice cracks radiating out from the corner. These are extremely difficult to manage and control. So much so, that you would most likely need a full isolation joint between the slab and the bump-out to have a separate, mini-slab, for the bump-out. Depending on how you will be finishing the floor, this may be more or less attractive.

^ My bathroom is inside my house, on the other side of my firewall. It allows me to keep the room rectangular, by bathroom toasty, etc. I just have to walk through two doors to "go" instead of one. ... No big deal.

I'm also trying to avoid building the house above unnecessarily large, so simply bumping out the garage foundation isn't an ideal option, either.

What are some other options for six cars? Design a simple three wide by two deep with three doors and resign myself to having to move one car to get at a "deeper" one? I don't like the idea of doors at both ends, either. Is there another configuration I haven't considered?

3 bay, stacked 2 high. (I use one bay just for auto work.)

This is where having an architect will really pay off for you. You can retain them to do conceptual work with you and they would keep you on track with zoning and aesthetics from the start. It would really **** for you to spend weeks on designing this and then find a show-stopper when you get to making actual plans.

 

[tacostand]

A lot of good suggestions.
I don't know the name, but there's a particular type of lift I've seen which might work... You park the first car under it and the second car on it. You leave the space between the lift and the door clear. When the lift is lowered, it places the car in the empty space and the car on the ground doesn't need to be moved. This way you can park 2 cars in a tandem (high ceiling) garage and never need to move one to get the other out.
I know I'm doing a poor job of explaining but hopefully it will jog someone's memory who knows the name of it or can furnish a picture.

 

[GMCGarage]

no bouncy bouncy on the first floor?

Obviously vibration and what not would be checked during the design.

 

[GMCGarage]

Yikes! The house is actually only 30 feet wide. This will require quite some structure to support on a 40 foot span.

A 40 foot wide house could easily be supported on a 40 foot basement, but that's not what he wants.

Im not sure I understand. The load would be less on a 30' span correct?

40' bays are common in office buildings, etc. Steel joists, deck and concrete.

Easily done, will just be more $$ than common wood floors.

 

[stm317]

Im not sure I understand. The load would be less on a 30' span correct?

40' bays are common in office buildings, etc. Steel joists, deck and concrete.

Easily done, will just be more $$ than common wood floors.

Sounds like the house will be smaller than the garage, but sitting directly above it, so you'll have at least one wall of the house that will stand somewhere in the middle of that 40ft span of the garage ceiling. Basically, all of the weight of the house (and everything in it) is going to sit above only a portion of the garage ceiling, rather than sharing perimeter walls. This will require a much stronger structure, or lots of additional support underneath those walls.

It's called a "distributed load" in statics, and it's not super difficult to engineer properly, but it is critical that it's done correctly by a pro or things could go very badly very quickly.

I can't find a perfect picture, so ignore the numbers in the following pic and focus on the primary parts of the drawing. Imagine that R1 and R3 are the garage walls, and the exterior walls of the house would sit above R2 and R3. The arrows on the right would be the weight of the house pushing down, and that rotation in the left-middle of the beam would be the ceiling of the garage trying to flip itself over because all of the weight is pushing down on one part, rather than all of it evenly.

 

[GMCGarage]

Sounds like the house will be smaller than the garage, but sitting directly above it, so you'll have at least one wall of the house that will stand somewhere in the middle of that 40ft span of the garage ceiling. Basically, all of the weight of the house (and everything in it) is going to sit above only a portion of the garage ceiling, rather than sharing perimeter walls. This will require a much stronger structure, or lots of additional support underneath those walls.

It's called a "distributed load" in statics, and it's not super difficult to engineer properly, but it is critical that it's done correctly by a pro or things could go very badly very quickly.

Oh, well then he should hire an engineer.

 

[nobbyv]

Sounds like the house will be smaller than the garage, but sitting directly above it, so you'll have at least one wall of the house that will stand somewhere in the middle of that 40ft span of the garage ceiling. Basically, all of the weight of the house (and everything in it) is going to sit above only a portion of the garage ceiling, rather than sharing perimeter walls. This will require a much stronger structure, or lots of additional support underneath those walls.

Correct, my current plan is to have the house above the garage sitting on only two of the foundation walls, with a steel I-beam or double-tee running the width of the 40' span for additional support. My current design also includes a foundation wall that only runs half of the length of the garage, terminating directly under where the I-beam would sit to give the beam itself additional support. Obviously, I need to run all of this by a structural engineer.

 

[wssix99]

Correct, my current plan is to have the house above the garage sitting on only two of the foundation walls, with a steel I-beam or double-tee running the width of the 40' span for additional support. My current design also includes a foundation wall that only runs half of the length of the garage, terminating directly under where the I-beam would sit to give the beam itself additional support. Obviously, I need to run all of this by a structural engineer.

My house/garage has this feature. I have one structural wall sitting atop my garage ceiling, which is actually two stories of reinforced concrete. ... I need a really big beam.

You will need a foundation the entire way around. If you don't have a continuous foundation - even in the section with no house around it, that end will heave in the winter and the house will want to break apart like a Kit-Kat bar.