Even Roofing Has Gone High Tech

Roofing has gone high tech and architectural. Unless you know the difference between your composites, your fiberglass, your aluminum, your ridges, hips and squares, replacing an old roof can be daunting.

In the old days, about a decade ago, slapping a new roof on your house was much simpler. There were about four basic roofing materials: the asphalt shingle, the asphalt and gravel flat roof, the wood shake and the Spanish tile.

Many Californians opted for wood shakes, blissful in their seeming ignorance of the potential fire hazard. But much of San Diego abuts open space stuffed with dry brush that can turn acres into infernos and send embers nestling into the nooks and crannies of wood shake roofing.

Finally the warning went out and many communities passed ordinances against wood roofing. Local homeowners, being Californians, were willing to settle for fake versions of what they liked so much in the past. Others caught onto the new products and began replacing more traditional roofing like terra cotta tiles and asphalt shingles with new products. A revolution in roofing materials was started.

Roofing becomes simpler when you remember that it is meant to keep the rain--no matter how infrequently it falls--off your head. Anything that keeps you and your house dry without catching fire is a good roof.

According to roofers, the rest is aesthetics.

Communities throughout North County have varying fire codes relating to roofing. For example, according to Dave Walter, fire inspector for the Poway Fire Department, Poway requires homes near wildland areas to be fitted with Class A fire resistant roofs. Class A roofs will not burn.

More urbanized areas of Poway, Walter said, may use Class B roofing, a rating that is nearly fireproof but will burn. Still, said Walter, the city does encourage all homeowners to opt for Class A. Most of the new products are rated Class A by Underwriters Laboratories.

There are other important considerations besides the fire rating. One is weight, which is usually measured in pounds per hundred square feet or simply "square." (The average house has about 25 squares.)

Replacing a composition shingle roof that would weigh between 220 and 370 pounds per square with a much heavier roof could cause structural failure if the frame is not beefed up. For this reason, roofers recommend, and some cities require, that a structural engineer advise homeowners who reroof.

Cost is also important. Roofing materials vary widely and most of the new products do cost more than simple asphalt shingles.

Warranty and aesthetics are the last two considerations. Some new products are warrantied up to 50 years with various limitations. As for looks, your neighbors may have a word or two to say. Assuming your neighborhood is not governed by strict regulations--such as Rancho Bernardo's call for red tile--you are free to use any material you want.

However, mixing materials on one street may have unwanted consequences. For example, replacing a red tile roof with asphalt shingles will lower the value of your home when compared to houses on your street that keep tiles.

There is little variance in installation. Most contractors will recommend removing old roofing, laying plywood sheathing and a 20- to 40-pound felt (tar paper) underlayment regardless of the roofing material.

All the roofing contractors and suppliers contacted by the Times stressed the need for homeowners to shop before settling on materials or a roofing company. New materials are coming on the market regularly.

Here is a brief look at some of the products:

Lightweight cement

This is where most of the revolution in roofing is happening. Lightweight cement roofing is meant to replace wood shakes or heavier traditional tiles. The cement is mixed with other substances such as cellulose fibers, or has air injected into the cement. At least one, Cemwood, manufactures its products so that butt ends and overall sizes vary to more effectively recreate a shake look.

These cement products weigh between 550 and 690 pounds per square as opposed to traditional tiles that can weigh more than 900 pounds per square. (One product, Maxitile, weighs significantly less than this figure at about 380 pounds per square.)

The cost for these materials varies, but normally range between $90 and $110 per square. Roofing contractors say $350 per square is "in the ballpark" for an installed price. These products carry warranties of between 30 and 50 years. Some brand names include Hardishake, Cal Shake, Maxitile, Cemwood and Permatek. Most carry a Class A fire rating.


Aluminum roofing has come a long way from the corrugated tin of yesteryear. The roofs on fast food restaurants like Dairy Queens are made from aluminum and many homes have opted for the same technology. Colors are baked onto the metal. The roof is installed in interlocking panels weighing only about 50 pounds per square. A few owners say aluminum is noisier during a rain and that they can hear the roof expanding and contracting with heat variances. Many like the heavy look aluminum gives. Aluminum carries a Class A fire rating. Alcoa and Classic are two brand names.


Although not a new product, Decratile from Cal-Pac is another alternative to shakes. It has a stone chip baked onto galvanized steel and weighs 150 pounds per square. The installed price is between $300 and $400 per square. It's fire rating is Class A and it carries a 50-year warranty.

Composition shingles

This old standby has been updated in two ways. First, many companies now use laminated fiberglass to lighten the load. Second, some companies now offer dimensional shingles to allow for some architectural creativity that can imitate shake. They are much lighter and cheaper than most new materials. They weigh between 220 and 385 pounds per square and cost between $50 and $60 per square for materials. Most composition shingles are rated Class A or B.

Modified bitumen or built-up roofing (BUR)

Although somewhat similar to the old hot-mopped roof that made the entire neighborhood smell like a highway project, modified bitumen can be applied either hot or cold and without the smelly kettle of tar. It is used mainly on flat roofs. It is made with a fiberglass base saturated with asphalt. New rubbers and plastics allow BUR to expand and contract without cracking, unlike many hot-mopped asphalt roofs. BUR is fire rated either Class A or B.


Although many people are replacing their shake roofing, some prefer to have old shakes treated to make them more fire resistant, or to have new shakes installed that have already been treated. Shakes range in price from about $105 to $150 per square for materials. Their fire rating will vary depending on the treatment. Shakes can weigh up to 700 pounds per square.


Clay tiles are still the choice for many homeowners, especially those in Spanish-style homes. Clay tiles almost always carry a Class A fire rating. There is a huge range in cost. For example, plain tile can cost about $60 to $100 per square for materials. Tiles with specially baked-on colors may run up to $300 per square. Their weight is roughly 900 pounds per square.

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