Radiant barrier is a heavy-duty aluminum foil that reflects 97% of the infra-red spectrum. It’s available on the underside of plywood roof sheathing for new construction, or in rolls for retrofits.

A fiber-reinforced radiant barrier, 48" wide roll.

Barrier stapled in rafter bay about 3/4" below sheathing.

Rolls can be stapled between existing rafters, an inch or so down from the underside of the sheathing. No taping is needed (unless you’re trying to make an air or vapor barrier as well).  This 4′ x 250′ roll is the perforated “Ultima” type from radiantguard.com – about $150 including shipping.

I stapled up the first couple pieces in the morning of a very sunny, 78° day, on this east-facing 12:12 roof. The infra-red thermometer shows a 30° difference in temperature by 10:30am.

East-facing 45° roof at 10:30am. Outside temperature was 78°.

Heat will also enter your attic by convecting off the underside of the sheathing, as well as by radiation, so a layer of insulation with air barrier below would complete this cathedral-ceiling job. But the radiant barrier alone would take a load off an uninhabited attic with ceiling insulation below.

In this application I’ve got a ridge vent. Intake vents lower would help. Either way, the increase in roof surface temperature with the installation of radiant barrier is only 3° – so little that composite shingle manufacturers have said installing the barrier would not void their warranties.

In my office though, I experimented with a pair of Ikea mirrors for more interesting light play. They’re mounted face up about 9″ down from top of glass, comfortably above eye level. The underside is painted white, to serve as a mini “ceiling” to the light reflected up from the venetian blinds below.

Mirrored light shelves reflecting sunlight onto ceiling

My office ceiling is the underside of a 12-in-12 pitched roof; the exposed surface is a dark grey polyiso insulation with merely a thin coat of white primer. Even so, the reflected sunlight on a clear day (center image, below) is roughly 2.5 times brighter than a pair of T-8 fluorescent tubes (right). Compare this to the ambient light of the ceiling — from light shelves reflecting the surrounding sky (left). Note that readings (in footcandles) are taken 12″ from the ceiling to isolate the light source for the meter.

Light readings for ambient, reflected sunlight, and dual T-8 fluorescents

In another project I inverted the concept, reflecting low winter sun down through skylights. Here the reflectors act to shade the skylights during the summer months. Specifics of this project are spelled out here.

South-facing, inverted reflectors over skylights to catch winter sun

For retrofitting windows, an interesting product called LightLouver based on the same principle as the light shelf has been developed as a vertical window treatment. I haven’t seen this in person, though, and don’t know how it compares to a standard polished chrome venetian blind.

Here’s a piece I wrote for the June 1993 Architectural Review. Shin Takamatsu had just designed his own exhibition in the top floor rotunda of the old San Francisco Museum of Modern Art, at the War Memorial Building on Van Ness…

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Photos from the article as published

To anyone already familiar with his work, the most surprising quality of Shin Takamatsu’s retrospective is its uncharacteristic grace. Mounted in the San Francisco Museum of Modern Art’s fourth floor atrium, and designed by Takamatsu himself, the space feels like the antithesis of the signature high-tech dazzle for which his buildings have come to be known.

Natural light filters down over white-draped pavilions, transparent walkways cross each other over a stone garden, the shoji-like skylight reflects in the glass underfoot. A tubular steel and glass torii arches one walkway as if to mark some modern Shinto shrine. But no, the visitor enters the space to a prattle of upbeat electronic soundtracks, dispelling any notion that he has perhaps found his way into the wrong exhibit.

The fantastic and highly personal style for which Takamatsu gained his notoriety abounds nevertheless in the work on display. Here the proclivity is to expend enormous effort detailing industrial-like accouterments, which, given a moment’s scrutiny, reveal themselves to be mere architectural tinsel. Ensembles of the stuff run gratingly against all conventions distinguishing architecture from sculpture .

But as the size of his commissions increase, the favor toward mechanical pretension has given way to abstraction and Takamatsu has adopted the curious practice of assigning function to his sculptural ephemera. New work seen for the first time here displays a predilection for large scale compositional play. In the Kunibiki Messe convention center, a glass slab frames a seven-story terrarium of platonic solids, each element housing a different activity.

Three other buildings were selected to highlight the exhibition; each was assigned to a pavilion with thumbnails, drawings, models, and most notably, a high-resolution computer display, continuously running a 3-D representation of the building. The introduction of such graphics affords a comprehensiveness the traditional renderings fail to achieve.

Few of the works, unfortunately, provide much spatial play for the new medium to exploit. The computer animated display of such a static volume as the Kirin Plaza Osaka, for example, tells us nothing we can’t glean from the models. The building first appears on the monitor as a reflection in the canal it fronts. Panning back, we see the building in what could be an expansive asphalt desert, not the neon-packed district of Osaka where it actually stands. (Perhaps paving the city like this was deemed more appropriate, given Kirin’s symmetry all but ignores its site.) We are taken from the canal around the exterior of the building: up the walls, across the facade, in daylight and at night, from this angle and that, but never from the inside, and always to the pop beat of electronic background music. The whole sequence smacks of a promotional — nothing is flaunted but the building’s chrome-fitted facade. There is irony in viewing this architecture through technology the building can only feign.

Of greater novelty is a twelve-minute, high-definition 3-D projection video. Museum visitors don stereo headphones and image-polarizing 3-D glasses for dramatic footage of existing Takamatsu behemoths. Cameras pan through and around the structures in Orson Welles-like sweeps; boom-operated camera work takes the audience on crane rides far from anywhere a visitor to the actual buildings might find himself. And, once again, each building muscles about the screen to its own theme song.

If the video footage is gratuitous, the implications of the computer sequences are significant. Space has always been the stumbling block of architectural representation. Perspective, the isometric, and even models have their inherent limitations. But the dynamic quality of computer animation has the potential to renew attention to spatial design, both in conception as well as representation. One hopes to see the medium employed in future exhibits, preferably for a less static body of work .