Monday, December 19, 2016

HEY BLOCKHEADS

Concrete block has always been the neglected stepchild of architecture. Even today, the humble material most us call “cinder block” still conjures up dreary images of warehouses, barracks and roadside motels.
Frank Lloyd Wright's Ennis House in Los Angeles
used his vaguely Mayan-looking "textile block" system.
(Courtesy Catherine M.  Austin, ASID)

A few architects have made noble attempts to change block’s image. In the 1920s, for example, Frank Lloyd Wright introduced a system he called “textile block”, in which custom-made blocks cast with various geometric designs were combined into a sort of tapestry in concrete, vaguely Mayan in appearance. A number of his better-known homes used the system, including the affordable-housing prototype “Usonian House”. Yet even Wright’s creative efforts failed to ignite the public’s interest in block.

Some years later, a lesser-known architect of the Prairie School, Alden Dow, devised a truly ingenious twist on the ubiquitous rectangular block: He designed it in the form of a parallelogram with equal sides—not just to be different, but so that he could build walls with perfect 45° angles as well as right angles. Dow built many intriguing homes using this method, but alas, the system passed away with him.

Back to the Sixties: An interesting use of screen block.
All right then, let’s face it: Outside of the Everglades, you won’t find many big fans of concrete block houses. Still, for do-yourself applications such as low garden walls, privacy screens, or foundations for outbuildings, block is unbeatable. It’s much less stressful to work with than poured concrete, since you can stop anytime you like—try that when you’ve got a dump trailer full of concrete starting to harden on you. And it’s actually lots of fun mixing and matching the umpteen patterns and colors of block that are available. Like Wright, you can weave a custom pattern of your own making. Here are a few concrete-block specifics:  

A split-face block, which is made by
extruding a single square block and literally
splitting it in half to produce a broken face.
•  Concrete block is technically referred to as CMU, for "concrete masonry unit". It isn’t cast, but is actually extruded through a die using a very dry concrete mix. The result is a masonry unit that’s relatively light, extremely strong and—let’s not forget—pretty darn cheap.

 Bond beam blocks used to strengthen a foundation.
• A standard concrete block is nominally 8” high by 8” wide by 16” long, so that when it’s laid up in a wall, the joints fall on the familiar 8” module.  However, 4” and 6” widths are also available, along with goodies such as end blocks, wall caps, and bond beams (special trough-shaped blocks that form a horizontal beam when filled with concrete, often used to strengthen walls or span openings).

Creativity makes a difference: This interesting combination
of block textures, colors, and sizes goes a long way
toward overcoming the usual concrete-block doldrums.
•  There are literally scores of different block types and colors available, so you needn’t load up on the usual dull gray variety. In addition to the familiar flat-faced block—available in a surprising range of colors—there are dozens of special types as well: Patterned block embossed with diamonds, triangles, or starbursts; screen block, which has variously shaped openings that form a pattern when laid up; and split-faced block, which imitates rustic quarried stone. Also available is slump block, a cousin of concrete block, whose bulges and irregularity are meant to imitate adobe.

•  Lastly, one caveat: Laying concrete block is a skill that’s not as easy as it looks, but can usually be picked up with a little perseverance. Before you go out and build that cinder-block Taj Mahal in your back yard, however, don’t forget that block walls must be reinforced with steel and then filled with a special thin mixture of concrete called grout. Leave out the rebar and grout, and you’re liable to end up with a lightweight pile of rubble.

Tuesday, December 13, 2016

GYPSUM BOARD MAKES "MASSIVE" WALLS EASY

Drywall makes it easy to produce massive-looking details
such as these arches. Note, however, that it's best not to mix
different styles of arches as has been done here.
Gypsum board—commonly known as "drywall" or "sheetrock"—has taken a lot of hits over the years, but despite its low-rent reputation, it's a marvelously adaptable interior finish. It’s relatively lightweight, easy to work, and lends itself to a variety of complex shapes.

With gypsum board, it's easy to create dramatic interior effects such as coffers, vaults and arches on even the tightest budget. All that’s required is furring (false framing) made from ordinary lumber, and a clear sense of the interior effect you’re after. To wit:

Wood furring or false framing is typically used to provide
a structure for attaching the gypsum board.
There are also many products that make it easier
to create arches and other details.
•  To make walls look more substantial, use furring and gypsum board to increase the “reveal” or thickness of the wall at openings such as archways. In many modern homes, the reveal is only about 4 1/2” (the thickness of a standard 2x4 partition)—one reason for the notoriously flimsy look of many postwar homes. Increasing this thickness to 8” or even 12” will produce a very dramatic effect of mass. Since your eye can only judge a wall’s thickness where it’s penetrated, you don’t necessarily have to furr the whole wall to achieve this illusion—just the area around the opening.

You can heighten the appearance of mass if you give openings a shape characteristic of masonry construction, such as flared sides or an arched top. Avoid designs using acute angles, since they’re seldom seen in masonry work. Also, to maintain the illusion of mass, be consistent—don’t have an archway passing through a supposedly massive wall that also has a skinny standard doorway in it.

Furring make these elliptical arches look massive.
Compare this example to the no-no at the bottom of the page.
•  If a streamlined or Modernistic look is more to your taste, capitalize on gypsum board’s ability to form curves. Curves are created either by slitting the back of the board, or by wetting it to make it more flexible.  Really tight curves usually require two layers of 1/4” gypsum board instead of a single layer of 1/2” board. Special rounded or “bullnose” corner beads are also available to complement the streamlined look.

•  Other effects such as tray ceilings, vaulted ceilings, niches, and complex archways are easy to achieve at modest expense. However, avoid fussy, overcomplicated details; bold, generous proportions usually produce the best results. If you’re unsure of your design, build a mock-up out of white cardboard before committing yourself.

A groin-vaulted ceiling using prefabricated furring
proves that almost anything is possible in gypsum board.
(Courtesy NH Drywall)
When combined with a smooth finish or veneer plastering (a thin plaster coat that yields an extremely flat surface), it’s not that expensive to get really impressive results.

Good results also depend on the accuracy of the furring underneath. Arches and the like must be carefully built up of wood to provide a solid backing for the gypsum board. Prefabricated furring pieces for creating arches and curves are available to simplify the job. Once the furring is complete, the gypsum board should be attached with drywall screws rather than nails—they’re less likely to disturb the position of the furring, and won’t pull out as easily.

Unless you’re experienced in gypsum board installation and tape-and-texture work, leave the creation of curves and special shapes to a professional.  A good tape-and-texture contractor can also help you figure out the most economical way of achieving the effect you’re after.  
To avoid a crackerbox look, don't put arched openings
in standard-thickness stud walls like this one.
Furr the walls out to make the arches more convincing.

Monday, December 5, 2016

ARCHITECTS AND C.A.D. DON'T ALWAYS COMPUTE

The sensual feel of a soft pencil gliding across clean vellum
has been replaced by a lot of clinical tapping.
Architecture, that most hidebound of professions, was long ago won over by the computer. CAD (Computer Aided Design), once the exclusive domain of huge architecture firms, is now virtually the rule in one person offices as well. 

In the main, CAD has been a blessing to the architectural profession. Having begun my practice in pre-computer days, I can testify that CAD has taken much of the now medieval-seeming drudgery out of architecture. By replacing paper and pencil with a computer screen, architects are no longer smudged with graphite by day’s end. Likewise, the hours of messy erasure once required to revise drawings is now a neat and simple matter of point and click. Powerful capabilities such as virtual reality are soon to come. 
Would architecture such as that of
William R. Yelland ever have
arisen on CAD....?
(Normandy Village,
Berkeley, California, begun 1926)

However, there's no denying that CAD has taken some of the romance out of architecture as well.   The sensual feel of a soft pencil gliding across clean vellum, leaving a crisp and charismatic hand-drawn line, has been replaced by the clinical tapping of keys and mouse buttons.               

Neither can the computer compensate for a lack of creativity. An architect who’s incompetent on paper is just as dangerous on a computer—his lines are straighter, that’s all. In fact, by concealing sloppy thinking in a tidy-looking presentation, computer drafting sometimes legitimizes a caliber of work that would otherwise not be passable. 

CAD contains booby traps even for accomplished architects. Too many are seduced by the easy flashiness of computer drawings, sometimes to the point where the process supersedes the product. For one thing, the tempting ability to copy and paste details with a computer can make an architect lazy, and it shows in some CAD-produced work. Details, and sometimes whole sections of buildings, become repetitive and rigid. 
...or Corbusier's Notre Dame du Haut at Ronchamps (1954)?

Operations that are difficult on a computer can influence designs as well. For example, drawing complex curves is quick and natural with a pencil, but relatively cumbersome with CAD. Hence, an architect may relent—consciously or not—to the simpler option of using straight lines instead. The idiom of the computer begins to dictate the idiom of the architect.  

In fact, it’s inconceivable that the fantastical, free-form Hansel-and-Gretel cottages of an architect like William R. Yelland—or even the sinuous carved details of Bernard Maybeck—could ever have arisen on CAD. The process is just too rational. Ditto for highly sculptural masterpieces like LeCorbusier’s soaring chapel at Ronchamps, which has scarcely a straight line or simple curve in it. This very shortcoming is, ironically, why an architect such as Frank Gehry requires a whole army of drafters using massive computing power to even approach the freedom of a hand-drawn design.
Ironically, it now takes a whole army of CAD technicians
to create a building that aims to look hand-drawn.
(Frank Gehry, Walt Disney Concert Hall, 2003)

Progress always brings tradeoffs, however. And as CAD programs continue to become more intuitive, designing on a computer may one day one day become almost as natural as drawing with a pencil.  

At the same time, though, we should recognize that architecture is closer to social science than rocket science. Architects must satisfy human beings, not just sets of numerical parameters. While computers can can help us sort out the cold-blooded logistics of door sizes and floor heights, they’re less useful in the creation of passionate architecture. They can never equal the power of a pencil in a sympathetic hand.