WHY ROOFS LEAK

The root purpose of every dwelling—one that dates back millennia—is to provide shelter from the elements.  Hence, an architect’s most fundamental charge is to design a weathertight building.  Unhappily, it doesn’t always work out that way.  One of the most common complaints I hear is, “Why can’t architects design homes that don’t leak?”  

The embarrassing fact is that leaky roofs are endemic to architecture, whether modern or traditional, and the caliber of the architect makes little difference.  The occupants of Frank Lloyd Wright’s most celebrated houses have been obliged to drag out buckets, bowls, and soup cans in many a rainstorm.  Or as a colleague of mine once put it:  “They don’t call it ‘Fallingwater’ for nothing”.    

For their part, architects are notoriously adept at brushing off the leak problem.  Wright once received a call from an irate client who complained that the roof was leaking all over her dinner guest.

“Tell him to move his chair,” he responded.  To the complaint of another waterlogged client, he calmly declared:  “If it didn’t leak, it wouldn’t be a roof.”

At least Wright fessed up to these shortcomings, however nonchalantly;  the same can’t be said for the famed International Style architect Le Corbusier.  Early in his career, he designed a building with a conventional pitched roof.  At the first snowfall, it leaked like a sieve—due, it seems, to his own inexperience.  In a classic piece of Modernist logic, however, Corbu concluded that the whole concept of pitched roofs must be flawed, and thereafter espoused flat roofs instead.

Ah, poor posterity!

Given that architects have such a hard time designing watertight roofs, what chance does a lay person have?  You’d be surprised.  Here are a few simple, common-sense suggestions that can help minimize the likelihood of leaks:

•  Keep the roof design as simple as possible.  Leaks seldom occur out in the middle of a roof’s flat surfaces—or “field”, in roofing parlance.  Rather, they tend to develop in the many nooks and crannies formed where roof planes intersect, or where roofs abut walls.  Hence, the simpler the design, the fewer the intersections, and the less the likelihood of leaks.   

Be especially wary of those craggy alpine roofscape favored by current architectural fashion.  All those cute little peaks and dormers can become a major leakage headache a few years down the road. 

•  Minimize “penetrations”.  In roofspeak, this term refers to pipes, vents, chimneys, skylights, and any other openings that interrupt the roof’s membrane.  Like intersections, they’re far more likely to develop leaks than the field of the roof.  Minimize the number of vents and flues penetrating the roof surface, and use a few large skylights rather than a lot of little ones.  And don’t locate skylights in roof valleys, where it’s difficult to seal or “flash” them properly.   

•  Avoid built-up (“flat”) roofs whenever possible.  Granted, built-up roofs are cheap, easy to construct, and great for covering oddly-shaped floor plans.  However, without conscientious maintenance—which they seldom get—built-up roofs simply won’t stay watertight.  A half-century of painful experience has borne this fact out, suggesting that our pitch-roof loving forebears were probably right after all. 

Sorry, Le Corbusier.

WHERE NOT TO BUILD

Travel down any residential street, and here and there you’re bound to find a few homes that scream, Addition!  Ironically, if you design an addition well enough, no one will ever notice it.  That may seem like a pretty sad reward for a job well done, but it’s a lot better than the alternative.

How to decide where to build your addition? Here are some guidelines to the fundamental decisions: 

• First, check your local zoning code to find out how high your addition can be and how close you can come to the property line. Just because your house is built to within a certain distance from the property line doesn’t mean the new work can do the same. Zoning codes change, and your addition will have to comply with the new ones, not the ones in force when the house was built. 

•  As a rule, don’t add on to the front of your house.  Chances are its facade--literally, “face” --was carefully composed by the original architect.  Messing with it can end up turning the Mona Lisa into Mr. Potatohead.   Take the sort of addition that’s commonly seen on California Ranchers, in which a couple of extra bedrooms are expediently packed into the crook of the “L” beside the projecting garage.  The resulting U-shaped plan gives the facade a pug-nosed profile and also reduces the entry approach to a dark tunnel.  In most cases, adding onto the front or side of the house is a better alternative.

• Take care to locate the new portion so it won’t cut off light to other parts of the house.  Consider where and at what time the sun currently enters the windows, and make sure the new work won’t throw crucial areas into permanent shadow.  An extra bedroom or bath is no bargain if it makes other parts of the house unlivable.   

• If you can’t avoid covering up an existing window, make sure it can be regained on another wall.  Don’t figure on replacing windows with skylights--they won’t provide the same quality of light, and building codes may not allow it.  And don’t resort to trading away east, west, or south-facing windows for north-facing ones--you won’t get the sunlight or comfort level you had before.

•  Lastly, beware the old myth that adding a second story is the cheapest and easiest way to add space. It’s hogwash. On constricted sites where no reasonable alternatives exist, second-story additions can provide a fine solution. In most cases, though, it’s preferable to build at ground level.  Here’s why: 

Second-story additions often require reinforcement of the existing foundation, making them no less expensive and frequently even costlier than ground-level additions.   They’re also inherently less space-efficient, since both levels lose appreciable floor area to the staircase.

But wait, there’s more:  It’s also much more difficult to integrate the towering bulk of a second-story addition into the design of the existing house, especially a quintessentially single-story design such as a Rancher or Bungalow.  Last but not least, second-story additions are far more disruptive, since they involve the temporary loss of a rather crucial part of your house--its roof. 

BLOWING THE BUDGET

“We had an architect draw an addition for us, and the bids came in at twice the budget!”  

That’s a complaint I hear all the time.  When you look at how architects are trained, and how they go about seeking a reputation, it’s no surprise that we’re so lousy at pinching pennies.  The truth is that the very meaning of life for most architects is rooted in self-expression:  we want our work to stand out from everyone else’s.  Alas, since a unique design costs more than a generic one, that self-expression comes at the client’s expense. 

Why are architects so motivated to be different? One reason is intrinsic to humankind, not just to architects.  For many of us, shaping a building in the intellect and then placing it in the physical world is our way of saying, “I was here.  This building is part of my legacy.  It’s one reason my life mattered.”  And obviously, we’d like our legacies to be memorable, not mundane.

But there are some less spiritual reasons that architects feel compelled to be different.  One of them has to do with the way we’re educated.  Many architecture schools simply amplify the student’s egocentric motivations, rather than balancing them with an equal sense of responsibility to the client.  

From their first day in school, students are praised for coming up with the unique, the extraordinary, even the bizarre.  Minimal emphasis is placed on budgets and other real-life encumbrances, on the theory that they might impinge on the student’s budding creativity.

“You’ll have enough worries about budget when you get into practice,” one professor told me.  “This is the time to let go of all that.”  Imagine a medical school operating on the same principle:  “Never mind the diagnosis—this is college.  Go in there and have some fun with that scalpel!”  

In the face of this relentless urging to be creative, most architecture students naturally come away with a sneaking guilt that any design that’s less than stunningly original isn’t worthy of the name architecture.  The result is that, for the rest of their careers, many architects aren’t satisfied with a simple solution when a complex one will do.  In other words, schooling teaches architects how to make buildings expensive, not how to make them affordable.    

Architectural education isn’t the only culprit, however.   We architects are also dupes to popular and trade publications that award extravagant architecture with the holy grail of publication, while work that’s more responsible to budget and function frequently goes unnoticed.  Since few architects are anxious to labor in obscurity, extravagant design becomes the norm even when it’s uncalled for.  

Hence, a simple addition or even a garage is trumped up into the architect’s personal manifesto, driving up the client’s cost to no practical gain. 

It’s not hard to understand why architects overbuild, when publication provides the only real way to achieve a measure of notoriety.  After all, it’s a rare architect who gets acclaim for designing something simple and inexpensive.

Picture the screaming headline:  “Nice Little House Comes In On Budget.”

POSITIVE, NEGATIVE

One of the simplest yet least understood concepts in architecture is that of positive versus negative space.  However esoteric it may sound, its applications to home and landscape design are immediate and tangible.

The basic idea is simple.  Imagine a rolled-out sheet of cookie dough.  Think of positive space as being the cookies cut out from the dough, and negative space as the pointy scraps left behind.  

In planning, just as in cookie-cutting, the name of the game is to minimize the sharp-angled or unusable scraps of negative space that are left over.  Alas, unlike baking, you can’t just gather them up and knead them into more dough--you have to figure out what to do with them ahead of time.  

The desirability of positive space is rooted in the fact that nature’s fundamental closed shape is the circle, or at least some approximation thereof.  And regardless of how far man removes himself from his primitive beginnings, circular shapes remain the most psychologically comforting for human habitation--a fact borne out by the widespread persistence of circular dwellings, from mud huts to yurts to igloos, despite the fact that they are not necessarily the simplest shapes to construct.   

We in the industrialized nations, however, live in a rectilinear world that’s chock full of negative space.  Outdoors, common examples would include those useless slivers of side yard that zoning ordinances insist on having between houses--the house, in this case, being the “cookie”.  Inside, negative space could include that dust-catching wedge of space under a stair, or that inaccessible corner of the living room that always seems to gather dust bunnies.  

There are a few simple ways to avoid negative space in architecture:

•  Avoid shapes having acute angles, both in plan and elevation.  Modern architects were (some still are) smitten with acute angles precisely because they’re rare in traditional architecture.  But while razor-sharp angles make for cheap drama, they don’t make for comfortable living--a fact vernacular builders have recognized for centuries.  Psychologically, converging surfaces are disconcerting, whether they’re in a sharp cornered room or a single-slope vaulted ceiling.  Physically, they’re just plain impractical.  Take a lesson from the past, and keep interior angles at ninety degrees or more.

•  Strive for areas with a circular sense of enclosure.  The closer a room arrangement approaches a circular shape, the more comfortable it’ll be.  This doesn’t mean the room itself should be rounded--just that the arrangement of the objects within it should be reasonably equidistant from a central focal point.  In a long, narrow living room, for example, a couple of more-or-less circular furniture arrangements would prove more comfortable for conversation than one long, stretched-out grouping.

•  Apply these concepts to exterior design as well.  Take a typical rectangular plot of land with an ell-shaped house in the middle:  the structure’s presence necessarily subdivides the outdoor area into smaller rectangular pieces, many of them awkwardly proportioned.  What to do with these negative leftovers?  

The best solution is to break down awkward negative spaces into a series of organically-shaped positive spaces--as many as are useful--and fill the leftover negative space with planting.   Note that size doesn’t determine whether the space is positive or negative;  even a triangular scrap of land a few yards on a side could be transformed into positive space by adding, say, a garden bench comfortably surrounded by a cloak of plants.