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Montgomery's McMansions will need to find a new purpose

Skeptics of Montgomery County's proposal to allow homeowners to build accessory apartments more easily claim it will change or harm single-family neighborhoods. But recent trends in housing suggest that those neighborhoods will change anyway.

The future of this Sandy Spring McMansion is in question. Photo by the author.

Slightly less than half of Montgomery households live in single-family homes today, and pretty soon they may no longer be the most common type of house in the county. According to the 2010 American Commun­ity Survey, just 49.9% of the county's 353,000 house­holds live in single-family homes. Another 31% live in apartments or condominiums, while the remaining 19% live in townhomes or duplexes.

Demand for big suburban houses or "McMansions" has waned in recent years, due to their high cost and shrinking households. Young adults aren't interested in them, either. Even those who prefer single-family homes would take a smaller house or a townhouse to be closer to jobs and amenities.

As a result, newly built homes are more likely to be apartments or townhomes. Data from the MoCo Planning Department shows that of 29,000 homes approved for construction here in the coming years, just 7,900 or 27% of them will be single-family homes. Those houses are likely to be smaller as well.

Nonetheless, there are still plenty of McMansions in Montgomery County: the 2010 ACS says that one-fourth of MoCo homes have nine or more rooms. What will happen to them? These houses will have to adapt to living arrangements they were't built for, and the single-family neighborhood as we know it may have to change as well.

Rainbow Mansion
Rainbow Mansion. Photo by dweekly on Flickr.

Some of these big houses might attract single adults, who find they can afford a nicer home if they share it with other people. Group houses aren't new to Montgomery County; in fact, they're legal if there's fewer than 5 unrelated adults in the same house. But they do present an opportunity to create small "intentional communities," where residents seek not only a common roof but a common purpose as well.

Take Rainbow Mansion, a 5,000-square-foot home in Silicon Valley home to a group of twentysomething tech workers. The home's founders describe themselves as "intentional community of driven, international, passionate, and socially conscious people trying to change the world":

It was more than just a luxury home full of brilliant young minds ... The Rainbow Mansion was an experiment in a new type of cohabitation. The house began hosting hackathons and salons in its library, inviting Silicon Valley's best and brightest to participate. "Right away it set itself in motion," [co-founder Jessy Kate] Schingler says. "It had this sort of accidental mystique about it."
A house that was probably built for a nuclear family has instead become the nucleus of a larger community. Of course, Montgomery County isn't Silicon Valley. But it's easy for me to imagine something like Rainbow Mansion appearing in a house near the Great Seneca Science Corridor one day. After all, there are over 500,000 jobs in MoCo, and young adults who seek the city life but work in Gaithersburg will probably live nearby rather than commute from the District.

Lennar NextGen Home Elevation
A NextGen home in South Carolina. Image from Lennar's website.

Other large homes may still draw families, but they'll be extended, multi-generational families, with grandparents, adult children, and other relatives and friends. They're living together to share expenses but may want some level of privacy and autonomy.

Today, MoCo's extended families can apply to build a "Registered Living Unit" in their home, basically an accessory apartment for a relative or home employee who lives there rent-free. There are only about 500 of these in the county today, but as multi-generational families become more common, we may see more of them.

Even home builders are picking up on the trend, adding apartments for extended family in new homes. Noting that nearly a third of American families have "doubled up" with relatives or friends, national builder Lennar Homes recently introduced a design called the "NextGen" home.

Lennar NextGen Home Plan
Floorplan of a NextGen home in South Carolina, with separate apartment highlighted in blue. Image from Lennar's website.

Called a "home within a home," the NextGen home looks like a typical single-family house on the outside, but inside is a separate apartment with its own private entrance, kitchen, and bathroom. Lennar hopes it'll be popular with immigrant families in which multiple generations live together.

While these homes are only being built in a handful of states like South Carolina and California, they have yet to make an appearance in the DC area. But Montgomery County's growing immigrant population suggests there may be a market for homes like this here.

For much of the 20th century, Montgomery County was known for big houses, great schools and affluent families. It's not surprising that civic groups call single-family neighborhoods the "backbone" of the county. While those neighborhoods may not be going away anytime soon, changing trends and changing demographics suggest they may look quite different in the future.

Dan Reed is an urban planner at Nelson\Nygaard. He writes his own blog, Just Up the Pike, and serves as the Land Use Chair for the Action Committee for Transit. He lives in downtown Silver Spring. All opinions are his own. 


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The conversion of many of the newer McMansions to mini-apartments is a definate possibility. As long as MoCo allows them, it seems like a great way to re-purpose those houses and its precedent is still visible in the large victorian rowhomes of DC that became rooming houses and now are little condo buildings in themselves. The only challenge I see is transportation. MoCo needs to coordinate their revised zoning maps with the BRT to make the most of these changes.

It's unfortunate for many who banked on their sub-dividion being the new Potomac or Chevy Chase, but it's also unfortunate for those building along the Bay when storms keep flooding their houses. Homeowners can't expect the government to bail them out every time they make a dumb choice.

by Thayer-D on Jul 5, 2012 10:35 am • linkreport

Is that Waldo in the Rainbow Mansion?

by Xavier on Jul 5, 2012 10:43 am • linkreport

I think the trend towards multi-generational households is understated. It will continue among immigrant families, but will pick up among non-imigrant families out of necessity as boomers money runs out and their kids have no choice but to take them in.

by spookiness on Jul 5, 2012 11:00 am • linkreport

The multi-generational angle is an interesting point given that there is an aging boomer population. I believe I heard that there will be more individuals aging into senior citizen status in the next 20 years in Montgomery County than have achieved that status in Montgomery in the entirety of its history up to this point. Whether residents choose to age in place, downsize, or find other housing scenarios remains to be seen. In the Rockville community of Aspen Hill, which I represent, residents have noticed a sharp rise in multi-generational occupancy of single-family homes in the last decade. While it that observation is anecdotal, it does at least point to some of the questions you address in the post.

by Del. Sam Arora on Jul 5, 2012 11:07 am • linkreport

I foresee issues with the HOAs contracts.

by Jasper on Jul 5, 2012 11:26 am • linkreport

Our neighborhood of 56 townhomes has at least 10 units with a single elderly person living alone. These are three bedroom homes of about 2000 square feet each.

I've thought a few times about how inefficient this is, economically. Maybe these homes could be modified to split them in two relatively unequal pieces, with a one bedroom apartment and two bedroom apartment.

Other than the traffic/parking argument, I haven't heard any good arguments why someone should not be allowed to modify their property in this way.

by Michael Perkins on Jul 5, 2012 11:30 am • linkreport

Other than the traffic/parking argument, I haven't heard any good arguments why someone should not be allowed to modify their property in this way.

The traffic/parking argument isn't a particularly good argument, either.

by Alex B. on Jul 5, 2012 11:38 am • linkreport

What type of square footage and number of rooms are necessary to be considered as a McMansion? The term is thrown around so much that it doesn't mean much.

by selxic on Jul 5, 2012 11:40 am • linkreport


You're right, the term "McMansion" does get thrown around a lot. For the purposes of this article, I used houses with nine or more rooms (the highest category available in the Census), though the ideas I mentioned could be applied to smaller houses as well.

by dan reed! on Jul 5, 2012 11:44 am • linkreport

@Alex B: True, but that's the only argument I've heard in which anyone other than the propery owners or occupiers could be affected.

Fire code? Safety? Living Space? These are all things that affect the person who owns the building or who lives in it.

With accessory dwellings, a house that used to have one or two occupants and one car could be modified to have four occupants and two or three cars. That does affect the neighbors, potentially. Parking more than traffic, most likely.

Once again, it comes down to cars taking up way too much space to store. In fact, for the floorplan in Dan's article, a parking space is about 70% of the same floor area of the accessory dwelling for that house.

by Michael Perkins on Jul 5, 2012 11:46 am • linkreport

There's always that fun "changing the character of the neighborhood" argument.

by Michael Perkins on Jul 5, 2012 11:47 am • linkreport

The floor plan of the so-called "NextGen" house is nothing more than a house with an "in-law" suite. That's been around for decades.

by Socket on Jul 5, 2012 11:49 am • linkreport

I think the term McMansion came about becasue of the cartoon like quality that new large suburban homeswhere slathered on treeless subdivisions, so it looked like McDonalds could have cranked them out. It started mostly as an aesthetic critique which now has a social critic component becasue of the recession. Maybe 3000 sqft and above with 6-12 gables, plastic trim, and three car garages prominently displayed on the front.

by Thayer-D on Jul 5, 2012 11:51 am • linkreport

That house in the first picture isn't a McMansion, it's just a classic large Georgian home with a sidewing. Looks a bit cheaply-built though.

by zac on Jul 5, 2012 11:57 am • linkreport

McMansion = big house, cheaply built. You want a real mansion but can't afford it, so you buy a big house that's built cheap, and the architects throw on some cheap ornamentals or couch it in a "style" to try to make it look better. Later on the term has evolved a bit to include big developments of these cheaply-built houses (i.e. mass-produced like McD's).

How is that first pic not a McMansion? It looks like one to me.

by MLD on Jul 5, 2012 12:10 pm • linkreport

Is this picture better? This is the house I was standing in when I took the picture above.

by dan reed! on Jul 5, 2012 12:12 pm • linkreport

I'm assuming that there's more, lots more, to the house that can't be seen in the pic. I can't understand why anyone would consider THAT a Mansion of any kind.

Face it, the term, McMansion is the same as NIMBY or means whatever the person writing it meamns.

Reminds me of the stories talking about Vincent Gray's Hillcrest "Mansion."

by HogWash on Jul 5, 2012 12:56 pm • linkreport

I guess my problem is that just about any new single family home can be vilified or considered a McMansion here. Even some apartments, condos, and townhomes are critiqued here for their size and build quality so it's hard to get a good idea of what is considered acceptable and for who and/or what that is acceptable for. Of course there is an irony to many of the homes lauded now originally being picked from a catalog or built in mass.

by selxic on Jul 5, 2012 12:56 pm • linkreport

Mcmansions are criticized for a combination of their absolute size, for being the size of traditional custom built mansions but being built in dull subdivisions like ordinary suburban houses (thus MCmansions) and for their specific architectural charecteristics, esp their combination of traditional (georgian or french baroque) detailing with features like multiple car garages, and their multiplicity of roof lines. The criticisms are architectural, planning, and social, though in many instances those come together.

For the purposes of this blog, whats relevant is the sheer size, I think, not the architectural details.

by AWalkerInTheCity on Jul 5, 2012 1:07 pm • linkreport

I'm not sure 9 rooms qualifies a house as a McMansion. I live in a 1500 sq foot 1950's ranch home and we have a (1) living room (2) dining room (3) kitchen (4) (5) (6) 3-bedrooms (7) small basement and a (8) garage. If you count the 2 baths as a room we're at 10 rooms in our house and it's definitely not a McMansion. I think that square footage is a much better indicator than number of rooms.

by David on Jul 5, 2012 1:18 pm • linkreport

It's also worth noting 1500 sq foot single family home is likely not the same as as 1500 square foot townhome or condo.

by selxic on Jul 5, 2012 1:32 pm • linkreport

Another approach might be considering the kind of layouts that used to be common in other cities (3-deckers, 5 deckers and duplexes, which sometimes included an additional in-law suite). These kinds of houses are flexible and function a bit like townhouses that have been cut into condos, but with yard space, which makes them more practical for families. Duplexes can be side-by-side or up and down. These all are flexible and sometimes people would build things like 4-plexes (two up & down duplexes attached to each other). One can own a part and rent the rest or people can buy as fee-simple units (rather than condos). This kind of housing fits multi-generational families well, as well as providing an income if one wants to rent out space. the latter day duplexes iI gre-up with in Cleveland were made to look like single family homes and easily complimented existing neighborhoods.

In Atlanta, "roommate" floor plans turn up as infill in gentrified areas. These essentially create 2 bedroom houses with good sized master bedrooms with bath. Sometimes these have been built as townhouses or in small groups of 2 or 3 that are attached to each other.

the point is--one can come up with any number of departures from the usual vernacular house in the DC area.

by Rich on Jul 5, 2012 1:55 pm • linkreport

For the American Community Survey, the Census defines a "room" as having a partition from floor to ceiling, and it excludes kitchens and bathrooms.

Open floor plans do not work well with this definition, I think.

by Miriam on Jul 5, 2012 1:56 pm • linkreport

Chris Leinberger's been talking about this for ages. is an especially non-rosy counterpoint to this optimistic article.

by sb on Jul 5, 2012 3:14 pm • linkreport

Anyone who has plans to make passionate love to their significant other understands the value of the classic single family house. As humans we crave status symbols, builders capitalize on this by using modern building techniques that can deliver what have been historically considered to be "high-end" accouterments at low cost (yielding high, high profit). These two forces (which are really unstoppable needs of human nature) dictate that, like throughout history, the SFH will always have a prominent place in every society for breadwinners that have issues with their masculinity (and breadwinners who have no problem with their masculinity).

For these reasons I find this article incredibly short-sighted. One cannot forget the tails of history, no matter how "new" today's economic fad may seem. Even the !Kung, whose radically different values compared to the Western experience teach communal property ownership, have definite huts to help define the boundaries between family and society. As participants in the human experience, we must understand the constancy of these values.

by funInSun25 on Jul 5, 2012 9:23 pm • linkreport

I just did a rough calc of the SF of the supposed small "nextgen" home - if you assume there is an upstairs that takes up about half the footprint, you are looking at an over 4000 SF building. That's HUGE! It's size is masked well and it's low-slung, but if you plopped that down in Fairfax or Rockville it would easily be a 700K home. If that's peoples' definition of small or efficient, well, we have a problem. The fact that it's a one-story home would in fact make it more expensive as well.

by stevek_fairfax on Jul 5, 2012 11:35 pm • linkreport

The fact there's confusion (apparent from the comments) about the definition of McMansion shows the author chose a poor word by using this term in the article. Houses > X sq.ft. might be a better term to use, since it's clear.

What I didn't realize, but I now see from the comments, is that apparently McMansion also implies poor build quality. So if a house is large but built well, then it's not a McMansion? The teardowns in Bethesda (infill) are usually large, but the build quality seems to be good and they use high-end materials, like Hardiplank instead of vinyl siding on the outside.

by Justin on Jul 6, 2012 7:50 am • linkreport

There's no such thing as good construction anymore, Justin. That is a thing of the past. The good ol' days... Now everything is machined and prefabricated with cheaper mass produced materials.

by selxic on Jul 6, 2012 9:09 am • linkreport

Maybe you where kidding, my snark radar is notoriously bad, but people haven't changed, just the technology. There where McMansions in the Victorian period as well, just better materials. As for good construction, I saw brownstones falling apart in Brooklyn that had newspaper stuffed in the walls for insulation, and stone layed so it splayed out to nothing. Greed and sloth have always been with us, what we've abandoned is any common sense of what is beautiful. One reason today's McMansions are much uglyer than a typical 1920's homes, regardless of size is that we've abandoned the study of scale and proportion, tools that would improve a building in any style. Instead we rely too much on novelty and extravagance. Not that these where absent in the good ol'days, but there dosen't seem to be the tempering hand of composition, something that was actually studied in the past.

by Thayer-D on Jul 6, 2012 9:27 am • linkreport

@Thayer-D: the bad stuff from the old days generally has not survived. What is left is usually worth keeping. This culling process has not yet happened for the new construction.

Brutalist architecture is presently going through this culling; it is generally not appreciated. We may be lamenting some of the finer examples of this, that currently is being torn down -- like Christian Scientist Church on 16th.

by goldfish on Jul 6, 2012 9:36 am • linkreport

Surviving through weathering the elements and time is completely different than being torn down becasue a style is out of fashion. Selxic was talking about good construction, not being out of style.

As for the "culling" of modernism, I'm not sure you can equate the protests against the demolition of the Post Office, Penn Station, or Grand Central to the demolition of the Christian Scientist Church on 16th. Not saying you're wrong to like that church, but an honest appraisal of peoples reaction to the demolition of various buildings of the past doesn't support your assertion that one style is as loves as another. Disharmhoy in music and abstraction in art will always have their place, but again, I don't think most people will miss a poured in place concrete box, but I could be wrong!

by Thayer-D on Jul 6, 2012 9:58 am • linkreport

@Del. Arora

"In the Rockville community of Aspen Hill, which I represent..."

You have a horrible way of representing your community (which is not part of Rockvilleb btw). Thankfully, not everyone in the State House is a sellout who says one thing to appease the constituents and then does the exact opposite, jeopardizing an extremely important piece of legislation.

It's one thing to be against something, but it's another to lie about it (especially to your constituents). I hope you enjoyed your short career in politics since you can't possibly hope to hold any representative position again.

by The Marylander on Jul 6, 2012 11:03 am • linkreport

Brutalism may have never caught on like other architectural styles, but it's an effective style for some uses, like university or administrative buildings. The clinical, utilitarian feeling it evokes is appropriate in these cases.

by zac on Jul 6, 2012 11:07 am • linkreport

If I was an architect in the 1950's and it was wall to wall Bauhaus grids, Brutalism would have been a cool glass of water on a hot day. Compared to a flat plane of glass and plastic rectangles, it has texture, structural logic, and some light and shadow play. Kind of like Michael Graves buildings in the 1980's with the kitchy historical motiffs, we might laugh at them now, but they where a needed reaction for thier times.

by Thayer-D on Jul 6, 2012 12:00 pm • linkreport

I'd like to know what is considered a "large house." I live in a 1700 square foot house built in the 1930's. Is that "large"?

Also, while the following is an interesting factoid, it means nothing without some historical context:

"According to the 2010 American Commun­ity Survey, just 49.9% of the county's 353,000 house­holds live in single-family homes. Another 31% live in apartments or condominiums, while the remaining 19% live in townhomes or duplexes."

Could the author tell us what the percentages were at earlier periods of time?

Finally, I think that as long as there are families with children, there will be a desire for single family detached homes.

by Andrew Pigeon on Jul 6, 2012 3:21 pm • linkreport

What to do with McMansions?

I like the casa colonica model, where families of farmers divide up the building and grow food on the former lawn for sale in the city.

Or banks could make them into halfway houses, or homes for Alzheimer’s patients.

No matter what, they’re going to be low-value, and only appreciated by folks with short-term interest in living there and getting out. Just like right now.

by Sydney on Jul 6, 2012 6:06 pm • linkreport

@Thayer D: Surviving through weathering the elements and time is completely different than being torn down becasue a style is out of fashion. Selxic was talking about good construction, not being out of style.

People put forth the extra effort necessary to preserve things they like when faced with "the weather". Consider Mt. Vernon, which would have fallen down due to decay if not for the devotions of the Mount Vernon Ladies' Association. The difference between what is saved and what is not comes down to the weather and the cost to restore -- where the line falls depends very much on how well regarded a building is. And this distinction is presently playing out on buildings at the end of their design life, 30-40-50 years old.

by goldfish on Jul 7, 2012 4:53 pm • linkreport

"The difference between what is saved and what is not comes down to the weather and the cost to restore"

It pretty much comes down to money, like everything else, not the weather, since the weather affects all buildings. If you put in the money to maintain a building, you will always mitigate the weather's effects, but again, it comes down to money, or 'capital' as republicans prefer.

"where the line falls depends very much on how well regarded a building is."

If only... How many "well regarded" buildings where lost only for profit or some ideoligical reason like the modernists and their idea that traditional cities where obsolete.

"Design life" is another term that ought to be retired. While it's true for some of the worst suburban commercial building types, proper maintenance can stretch 40 years into 140, if there's money. Maybe financial incentives ought to be provided to maintain or repurpose existing structures for the sake of sustainability, but if someone want's to make more money from the property, no amount of free money will convince most landlords to maintain an underbuilt lot, unless we all agree its worth preserving.

by Thayer-D on Jul 7, 2012 7:26 pm • linkreport

@Thayer D: "Design life" is another term that ought to be retired. While it's true for some of the worst suburban commercial building types, proper maintenance can stretch 40 years into 140, if there's money.

Nothing lasts forever. Even the pyramids have deteriorated. The life of a contemporary building is a few decades, because at a certain point it is cheaper to replace than rebuild. Stick buildings are the shortest-lived; masonry is the longest.

People maintain and restore things they love. If not for that, nothing would survive past its useful life.

by goldfish on Jul 8, 2012 7:00 am • linkreport

I think we're saying the same thing, just coming at it from different angles. You say love, I say money, but while I agree these seemingly contradictory statements can co-exist... "Nothing lasts forever" and "People maintain and restore things they love", you need money to show a building love.

I guess my issue with the term "design life" is that it seems reponsible for the idea of built-in obsolesence, especially in an time of diminishing recources when we should be promoting sustainable construction. In our time of constantly evolving technologies and movement of people, the psychological benefits of a sense of permanence should not be dicounted.

by Thayer-D on Jul 8, 2012 4:08 pm • linkreport

@Thayer D: Yes I think you are correct.

However, about "design life": this is dictated by the economic conditions that make it desirable to build something in a given location in the first place. These change with time, so it does no good to build something that will outlive its usefulness, when it will need to be torn down. Examples: RFK stadium; Hine middle school; the Benning Road Pepco plant; the 900 NJ Ave trash transfer station. These are well-constructed buildings that have to be torn down at great cost, because their original use is no longer supported -- so why build it to last longer?

by goldfish on Jul 9, 2012 12:17 pm • linkreport

The reason to build something to last longer is two fold
1 - You might run out of recourses to tear down and re-build constantly, as has happened throughout history, so re-purposing a building is the most sensible thing to do.
2 - Temporary buildings don't do anything beyond sheltering to create a sense of place and well being.

Take a walmart in the suburbs, it will never contribute to something greater, so maybe there's a justification for cheap construction. Build a department store in town and it might become an office building or apartment building. RFK doesn't "need' to be torn down except that one can make more money from a larger arena. Like I said earlier, the idea of "design life" has it's place, but look at the new article on the "obsolescence" of many inner city DC neighborhoods, and one can see how subjective that term can be.

by Thayer-D on Jul 9, 2012 3:54 pm • linkreport

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