Accessory Dwelling Units

[MNdible]

Not sure, but the code may also be responding to some fire concerns here as well. Existing wood clad/framed houses are often built too close together to meet the current code but are grandfathered in -- this doesn't mean that new ADU's would get the same treatment.

[EOst]

I think previous news coverage had her essentially arguing that because North Minneapolis has a problem with slumlords subdividing old homes illegally that we shouldn't make it legal. It was a bizarre argument, frankly.

So really, she doesn't want renters in the couple white neighborhoods up by Victory. Got it.

[twincitizen]

Is there a minimum lot size required to build a detached ADU? I assume it would be legal on the standard 40' wide Minneapolis lot, as long as you can meet the various setback and building separation minimums.

Also of interesting note, while researching this ADU policy I discovered that Minneapolis' parking minimums for a single family dwelling are quite low. For a single family dwelling, Minneapolis requires just one off-street parking space, which does not have to be covered/garage/etc. It can simply be a single space on a concrete slab off the alley, for example. So you could theoretically build a detached ADU on your property that is not necessarily above a garage or attached to one. The ADUs themselves do not trigger any additional parking requirements, which is pretty awesome.

[RailBaronYarr]

Also of interesting note, while researching this ADU policy I discovered that Minneapolis' parking minimums for a single family dwelling are quite low. For a single family dwelling, Minneapolis requires just one off-street parking space, which does not have to be covered/garage/etc. It can simply be a single space on a concrete slab off the alley, for example. So you could theoretically build a detached ADU on your property that is not necessarily above a garage or attached to one. The ADUs themselves do not trigger any additional parking requirements, which is pretty awesome.

Yeah, we kvetch about parking minimums a lot here, and MNdible busts our chops a bit since the rhetoric really rings true in Houston, LA, NY, etc but we're fairly progressive about it. So that's good. I was suuuper worried that parking minimums would be present in the first pass at this, and it was the biggest sigh of relief for me, mainly because many cities with ADU ordinances in place have 50' lot widths as a general standard, while ours are typically 40 (mine is 42, luckily). 50' is a lot easier to fit a full ADU with setbacks and a pad parking spot to the side, and allows for a little more flexibility in design. Vancouver also has a lot of 33' lots, and their design book handles it well, but it's nearly impossible to have an ADU parking spot AND one for the main unit on that skinny of a lot.

[twincitizen]

Bloomington allows ADUs: http://bloomingtonmn.gov/cityhall/dept/ ... andout.pdf

Who knew?

The minimum lot size is 11,000 square feet, which roughly translates to an 85' wide lot, which is actually pretty standard in Bloomington. Only the far northern areas of the city have 75' lots and would be ineligible. They're allowed in the single-family zoned areas all over the city, too (not restricted to a particular neighborhood).

The only major difference from the policy Minneapolis just enacted is that Bloomington does not allow detached ADUs. They allow internal and attached units, and they must be built to maintain the outward appearance of a single family home (though the ADU must have a separate, external entrance). They have an owner occupancy requirement like Minneapolis.

All in all, pretty damn impressive for a suburb! Not only that, but they enacted this ordinance way before Minneapolis, so bonus points for that!

EDIT: I found this Roseville document indicating that they allow ADUs with a conditional use permit in some areas. It also provides a summary of Shoreview's & Bloomington's policies. http://www.cityofroseville.com/Document ... /View/4640

Anyone know if other burbs allow ADUs?

[xandrex]

Roper mentioned that Bloomington allowed them back before the Council vote. But he didn't mention any other suburbs.

http://www.startribune.com/local/west/282352381.html

[Andrew_F]

I don't have a list in front of me right now, but there are a whole host of suburbs and smaller cities that allow ADUs-- though with heavy restrictions that really make them a whole different animal than what is being proposed in Minneapolis and the sort of examples that most of us picture when we think of urban ADUs.

[Tyler]

So I was reading through the code on ADUs and came away confused.

It seems to me that on a typical lot a two car detached garage with ADU above is all but impossible. This is due to the 676 sqft maximum floor area including the garage space itself.

Is this intentional? Or am I missing something here?

[FISHMANPET]

Floor area means the space the building takes up on the lot, not the total space of all floors. So the code allows a 26x26 foot structure, probably 2 stories.

[Tyler]

I don't think that is correct. ie. 2500 sqft max GFA for primary structures does not mean per floor.

Floor area, gross (GFA). The gross floor area of a building is the sum of the gross horizontal areas of the several floors of the building measured from the exterior faces of the exterior walls, or from the centerline of walls separating two (2) buildings. The gross floor area of a building shall include basement floor area when one-half (½) or more of the basement height is above natural grade for more than fifty (50) percent of the total perimeter. The gross floor area shall also include elevator shafts and stairwells to each floor, penthouses, attic space having headroom clearances that meet building code minimum ceiling heights, interior balconies and mezzanines, enclosed porches, floor area devoted to accessory uses, and floor space used for mechanical equipment, except equipment located on the roof, unless otherwise specified in this chapter. The gross floor area of structures devoted to bulk storage of materials, including but not limited to grain elevators and petroleum storage tanks, shall be determined on the basis of height in feet, assuming one (1) floor for each fourteen (14) feet in height. In determining the gross floor area of an individual use within a multiple tenant building, the gross floor area is the sum of the gross horizontal areas measured from the interior faces of the interior walls of the space occupied by the use. Except for garages attached to single- and two-family dwellings, gross floor area shall not include space devoted to accessory off-street parking or loading facilities, including aisles, ramps and maneuvering space.

[FISHMANPET]

Er, yeah, that's correct. I don't think the 676 is gross floor area though.

[Tyler]

Yeah, duh. It says the word "footprint" right in the code. Somehow missed that on multiple readings. Thanks.

Code: Select all

When a lot includes a detached accessory dwelling unit, the combined floor area of the footprint of the detached accessory dwelling unit, and all other accessory structures and uses designed or intended to be used for the parking of vehicles, shall not exceed six hundred seventy-six (676) square feet or ten (10) percent of the lot area, whichever is greater, not to exceed one-thousand (1,000) square feet.

[FISHMANPET]

We wouldn't want to make these codes human readable no sir.

[RailBaronYarr]

Yes, the footprint of the accessory structure must be no greater than 676 sqft (or 10% of lot area, whichever is larger). But detached ADUs allow up to 1,000 sqft of total floor area, including parking and half-story area. That means a 676 sqft footprint 2-car garage could have a 324 sqft apartment above it by-right. Or you could build a two-story structure with a footprint of 500 sqft (ex. 20x25), and devote as much as you want of the main level to parking. Or any combination in-between.

[Tyler]

I think they should have allowed a 24x24 garage with ADU above. 1152 Sqft total.

[MNdible]

If your roof slope cuts into the second floor square footage at all, which is very common in Minneapolis four squares, you'd still be under 1,000 with a 24'x24' garage. Or if you go to a 22'x22' garage, you could still have a full second floor.

[twincitizen]

Huh.

Minneapolis allows detached ADUs (incl. garage space) to be up to 20 feet tall*, but garages otherwise are limited to 16 feet (and even then only if the garage matches the materials of the house, etc. Non-matching garages are limited to 12 feet in height)

*height is measured at the midpoint between peak and eave. The peak of a garage/ADU may not exceed the peak of the principal structure (house) in any case.

The city I work for largely borrowed from Minneapolis' ADU policy when we crafted ours last spring. I am beginning to think we were overly permissive on two-story garage height (including garages without an ADU). Also interesting to learn that Minneapolis caps garage floor area (footprint) at 676 sf for the vast majority of lots (or 10% of larger lots, up to 1,000 sf). Essentially you cannot build a 3-car garage in Minneapolis, unless your lot is at least 60' wide or more. Whereas the city I work for, you can build absolutely monster 1000 sf garages on 50' wide lots. And now our "ADU/taller garages" ordinance allows garage heights potentially up to the height of the house (18' max on lots under 75' wide, 25' tall on lots 75' and wider). The latter I think is too much...it should probably max out at 20' like Minneapolis.

[mattaudio]

Can we also address the bigger reason why these aren't taking off? The ridiculous owner-occupation requirement. I'd love to build an ADU - and I have no intent of moving away from my property - but I don't want to take away real value on my property as it relates to future opportunity costs. And it's not just what I want to do - it would be harder for anyone to sell a property with that restriction placed in the deed.

[winterfan]

Can we also address the bigger reason why these aren't taking off? The ridiculous owner-occupation requirement. I'd love to build an ADU - and I have no intent of moving away from my property - but I don't want to take away real value on my property as it relates to future opportunity costs. And it's not just what I want to do - it would be harder for anyone to sell a property with that restriction placed in the deed.

I'm not sure that's the only reason, but I agree. I wouldn't want to buy a house that had restrictions on it. I have no plans to ever rent out our house, buy you never know what the future holds.

Personally, right now, the only reason I would build an ADU is if my elderly parents had to move in with me. If it came to that, it might be a better idea to just build an addition with a bedroom and bath off the back of our existing house. Our lot is a little weird anyway. Construction costs would probably be a fortune and I'm not sure the ROI is there.

[seanrichardryan]

Cost. Not many people have 60k-80k sitting around to build an apartment, especially if they currently have a fully functional garage that isn't in need of replacement. ROI is for or more years and it would seem they'd choose a kitchen remodel or another bathroom first.