Shake, Rattle, & Research
At the UCSB exhibition on ranch houses last week I met the owner of a 1960s Cliff May-designed house who impressed me with the care he has taken in replacing the original shake roof on his 60+ year old home. Restoration projects can be problematic. His modern lightweight cement tile solution,
shown here, is successful because it remains true to the roof’s original architectural character while accommodating today’s fire codes. (Even if new wood shakes could be made non-combustible they would be prohibitively expensive.) I think Greg’s experience is useful for anyone thinking about roof replacement.
He used a Boral roofing product called Cedarlite 600 — which is designed to mimic heavy wood shakes — in a color called Silverwood (originally from Monier Lifetile). The 600 refers to weight: a 100 foot-square of Cedarlite 600 tiles weighs 600 pounds and there are 120 pieces to a square. According to Greg: “It’s a lower-density concrete tile with the primary disadvantage that it’s not as strong and walkable as the heavier concrete products.” Using heavier tiles might have meant beefing up structural support. Here are some Cedarlite examples.
Greg likes the texture and says “It looks reasonably like shake but all the tiles are the same size — although there is variation in the molds and colors of the tiles. They can be slightly staggered but that makes it really easy for the corners to be broken off. Looking at the roof at a certain angle you can see diagonal patterns going up the roof. Most people don’t notice that but once you’re familiar with it that becomes the signature in verifying that Cedarlite 600 or it’s slightly denser cousin Madera 700 is what you’re actually looking at. I felt it was the best shake alternative available.”
Greg was worried about walking on the roof — for maintenance , clearing leaves and such. I spoke with Boral representative Altie Winters about this and she said that if you need to walk on a Cedarlite roof you should wear sticky shoes like sneakers and step where the tiles overlap and avoid the center of the tile itself. Greg used a polyurethane expanding adhesive in lieu of nails. “The idea,” says Greg, “is that it provides a cushion in the air gap under the tiles which enhances the support when walking on it. It does seem to help quite a bit but you still need to be as careful as possible. At least when the tiles do crack they tend not to move since the adhesive is applied to much of the bottom. Supposedly this material also provides an R-4 insulation value as well. The polyset product was originally designed as a hurricane solution to eliminate the pitfalls of nails coming loose. In the West they market it as a walkability solution. So knock on wood that it will stand the test of time. We’ll see.”
SIDE NOTE: Boral recently introduced an intriguing product called the Boral Pure Smog-Eating Tile. According to Boral, the concrete roof tile’s coating contains a photocatalyst activated by daylight, which helps convert harmful nitrogen oxides into calcium nitrates. A 2,000 square foot roof of these tiles can oxidize the same amount of nitrogen oxide that a car produces from being driven up to 10,800 miles. So far the tiles only come in Mediterranean profiles that
resemble terra cotta, as shown above. Maybe they will produce a smog-eating shake look-alike too, some day.
Shakes weren’t the only roofing material in Cliff May’s repertoire; he also used terra-cotta — on some of his larger custom houses he aimed for a rough hand-crafted look — and occasionally even standing seam metal. Perhaps his
most exotic choice was ocatillo branches, as shown above, to create a shade canopy over the pool at a marvelous oasis-like house in the desert near Tucson, Arizona. According to the owner the branches need to be replaced about every ten years.
The wide glassed-in or open gable, sometimes with a ridge skylight running
down the middle — as shown here at the splendidly expansive house that’s part of Bronzewing Farm, two hours north of Sydney, Australia — became a signature feature of Cliff May’s work. Incidentally, this roof retrofit used a composite tile (not concrete) and works very well. (Photograph by Joe Fletcher for my ranch house book — shameless self-promotion department!) Such features have
inspired contemporary designers like Dan Tyree in Plan 64- 172. As Greg Friedman might say: such roofs are worth preserving with a little research and a light step.