What is a McMansion?

by Erik North on February 11, 2012

What is a McMansion?


McMansion was already a derided term years back prior to the recent collapse of the housing market. Since then, it’s become symbolic of the rampant over construction as prices ballooned. The bloated McMansion (though my favorite term is ‘Garage Mahal’) has been so conceptually discredited that the NAHR reported that the average size of new construction has declined for the first time in over 50 years.

Everyone knows McMansions as the bloated, cheese puff eating cousin of modern housing but pose the question: “What is a McMansion?” and you’re liable to garner a slight pause. It turns out that this uncertainty isn’t a mistake but rather a design feature.

What is a McMansion?

I read an apt summary of the McMansion concept once, that they are ‘buildings that have been designed from the inside out.’ McMansions, if they have any definition, are houses of no distinct style other than being an over-sized mish mash of features homebuyers find desirable.

McMansions are multi-storied, usually occupy a significantly larger footprint than other nearby houses or as part of a McMansion subdivision (and who wouldn’t want to live there?).

The McMansion exteriors usually have columns, Palladian or full-length windows, multiple dormers, complicated multi-plane rooflines and mutliple contiguous additions with a very large (3+ cars) attached or unattached garage.

The interior is chock full with every selling point amenity the builder can cram in there. Master bedrooms, walk-in closets, multiple fireplaces, display kitchens, man caves, finished rooms over garages, entertainment rooms, granite counter tops, hot tubs in the bathrooms, bathrooms in the hot tubs, and what the heck a few more bathrooms, etc. Have you noticed the one thing I haven’t mentioned?

Energy and energy efficiency. D’oh.

McMansions and Energy

McMansions are the SUV of houses; they’re way bigger than you need with loads of attention paid to customer enticing amenities and none at all to energy performance. Because there aren’t any formal design standards, you can’t point to style specific issues, like with a Ranch or Cape Cod. However, there are some general issues that crop up from prioritizing snazzy amenities over building basics.

McMansion – Finished Basements

Finished and walk-out basements are a great addition to a house if done right. Ahh, there’s the rub. I’ve said more than a few times that folks dig foot holes into clay and mud, then act surprised when they get wet. There are basement systems which work fine but they must deal with moisture.

Too often McMansions finish their basements with standard framing techniques 2×4 studs, top and bottom plate, fiberglass batts (Kraft paper in) and drywall. The key here is that there is wood, kraft paper and the drywall paper facing, all chock full of plant fibers and all potentially mold food.

I’ve seen many basements framed in this manner which were fine either because of a very dry basement or no vapor barrier which allows some drying (or both). But standard framing in the basement can lead to potential mold issues.

McMansion – Heating Distribution

Like a lot of these issues, there’s no real reason to have problems distributing heat through the house, no matter the size. Whether a hot water or hot air system, the boiler/furnace can be sized appropriately and heat moved around the building. However like the insulation, a McMansion’s focus is rarely the heating system.

Finished rooms over garages, finished basements and man caves are the focus. If that means running uninsulated copper or PEX tubing next to uninsulated sills or unsealed vented soffits, so be it. And when the 3rd floor isn’t heating or the pipes freeze that run along 120 feet of uninsulated sills, well, it must be a problem with the heating system.

McMansions – Chimneys

Fireplaces add a nice ambiance to any house, evoking Colonial times. McMansions often have multiple fireplaces. Because who wouldn’t want a fireplace in their bathroom? The problems here are threefold (unless you don’t like the wood smoke, in which case four-fold).

First, the wood framing around chimneys is one of the most notorious air leaks in any house. Having several means several most notorious leaks. Due to the often complicated roof structures, the chimneys can be very hard to access.

Second, builders sometimes install propane or natural gas fireplaces. The horror. I mean, that sounds pretty nice … what’s the problem? The problem is that carpenters and gas techs don’t usually talk to one another before work.

Suppose you have a blueprint which designs for wood fireplaces and the developer installs gas ones instead? Well, your exhaust just went from a full brick chimney to a 6 inch gas vent. And someone, anyone had better seal that enormous 9 square foot hole in the attic. Don’t assume it’s ‘just done’ … I once saw that exact setup and it was covered by three fiberglass batts.

Third issue if you do have active wood stoves, you’re storing a lot of wood. This wood is often dried indoors. A cord of green wood will dry out thousands (yes, thousands) of pounds of water. A gallon of water weights a bit over 8 pounds – can you imagine dumping 250 gallons of water on your basement floor?

McMansions – Attic Venting

McMansions are usually built with exceedingly complicated roof structures. The clean plane is broken with dormers, multiple roof lines, hip roofs and other complicated elements. How can one effectively vent a roof that looks to be going out of its way to be difficult?

McMansion roof

And...we vent this how?

In a word, you can’t ventilate it or at least not in a manner that would be effective.

McMansions are the culmination of a particular conception of modern housing. It puts size, amenities and stylistic elements (though not a unified style) over function. There are often difficult to address heating and efficiency issues overshadowed by nice granite countertops…until winter.

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