Thread by @alfred_twu

Missing middle housing - fourplexes, townhouses, etc - is great for most places. However, in places like Palo Alto, where land is north of $20 million an acre, it's time to look at Missing Large Housing, specifically, ways to build, plan, & finance big buildings cheaper. 1/

For all the stereotypes about individualism, Americans are social people. From block parties to music festivals to professional sports, many of us love being in a crowd. However, as we've grown rich and want more living space, we've outgrown our Main Streets. 2/

Now, not only is their a shortage of housing, there's also a shortage of customers for local businesses. As a result, a low-rise Main Street that used to have enough people to support lots of stores no longer does today. 3/

The places where Main Streets are still thriving are ones where there's still overcrowded housing: college towns, immigrant neighborhoods, and tourist towns, where hotel rooms provide high customer density. 4/

For most of us Americans though, we like to have more space than a bed in a shared room. Having a successful local economy should not mean having overcrowded housing. 

And therefore, if Main Streets are to stay in business, there needs to be more living space above. 5/

Main Street 100 years ago: crowded, low rise buildings. Main street today: uncrowded, but stores closed.
Main street tomorrow: Tall building with spacious housing and active businesses.

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How much housing space does it take to support a business? On average, 600 square feet of housing (a one-bedroom apartment) for every 10 square feet of retail. This doesn't mean 60-story buildings - not every street needs to be a shopping street, but it does mean a lot more. 7/

The go-to method for urban housing is the mid-rise podium building: 5 floors of homes above parking & stores. This design can be costly, requires large sites, & when limited to major streets, there aren't enough people in the city to support businesses to fill the storefronts.
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Let's look at some other ways to do it.

Small Lot Redevelopment:
When most land in a city is already divided into small lots with individual houses, even if zoning is changed, larger buildings come slowly since most homeowners don't have the money or skills to be a builder. 9/

In Greece, the issue of homeowners with land, but no money to redevelop, led to Polykatoikias being built using the antiparochi, or "Supply in Exchange" system. The homeowner supplies the land, and in exchange gets a few apartments in the new building. 10/

Learn more about Greece's Polykatoikias here: en.wikipedia.org/wiki/Modern_ar…
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In Vietnam, narrow lots - some just a single room wide - led to tall row houses. Known as tube houses, this pattern went vertical as families grew wealthier, allowing extended families that had previously crowded into a single floor to spread out across many floors.
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In Germany, building groups - baugruppen - is a system where friends gets together & develop for a building that they'll all live in. In addition to savings from pooling resources, there is also an opportunity for greater customization. housing.wiki/wiki/Baugruppe @housing_wiki 13/

For those who want more shared space in their custom community, cohousing includes shared spaces such as playgrounds, a clubhouse, or gardens. en.wikipedia.org/wiki/Cohousing 14/

Prefabricated concrete panels save costs by mass production & shifting work from construction site to a factory. Panels reached their height of popularity during the Communist era, & still exist in large numbers today. For example, in Czechia, 1 in 3 people live in a panelak. 15/

Concrete panel apartments continue to be built today, including in the United States. forconstructionpros.com/concrete/press… 16/

While panel buildings only prefabricated the walls, modular buildings come as pre-assembled rooms. While modules are also long and narrow to allow them to be trucked to the site, they are wider, taller, and better insulated than shipping containers. 17/

Mid-rise modular buildings use load-bearing modules stacked directly on top of each other, while high rises attach modules to a frame. 18/

Even modular concrete & steel are expensive & require a lot of energy. As a result, most housing in the USA is built using wood - 2x4's & plywood. Structural strength / fire hazards limit conventional wood to several floors.A new system has been invented: Mass Timber. 19/

Also known as Cross Laminated Timber, it involves gluing wood into giant beams & slabs strong and fire resistant enough for high rise construction. 
In the 2021 International Building Code, mass timber buildings will be allowed to have 18 floors. en.wikipedia.org/wiki/Cross-lam… 20/

One challenge the private housing market faces is the boom & bust cycle. In the boom, labor &materials get scarce. In recessions, suppliers go out of business & workers change careers, slowing recovery. US homebuilding collapsed during the 2008 recession & has yet to recover. 21/

A public sector developer stabilizes the market, providing the steady demand needed for investment in modular building factories, job training, and material suppliers. It can also ramp up construction during recessions as part of the stimulus. 22/

In the past, the US government subsidized suburban housing with cheap mortgages & money for highways that brought lots of land within commuting range. Nowadays, transportation projects - both road and rail - are popular during recessions to stimulate the economy. 23/

In addition to infrastructure that helps get people to work, stimulus could also build homes close to jobs. With a large economy of scale, public sector developers pass savings onto residents and can cross-subsidize some homes to be even cheaper for low income residents. 24/

Large social housing complexes contain more than housing. Like any large planned development, they are often built with businesses, schools, parks, transit stations. 25/

At the very large scale, there is the satellite city. More than just a bedroom community, these are real cities with a downtown, anchored into the regional economy by a large institution such as a college, government agency headquarters, or medical center. 26/

Satellite cities do not have to be brand new. They can be grown from an existing suburb. Large sites such as shopping malls, golf courses, or train station parking lots are good locations for building a new high density core for a satellite city. 27/

same info in article format: alfredtwu.medium.com/missing-large-…

and that's all for tonight. coming around next time: missing small housing, a look at mobile home parks, small lot subdivisions, dome homes, and more. 28/

And here's the thread on Missing Small Housing. 29/