Building Principles: Wisdom Overhead

Rick Stryker, PE
November 2015

American poet and diplomat James Russell Lowell is quoted as saying, “Compromise makes a good umbrella, but a poor roof; it is temporary expedient, often wise in party politics, almost sure to be unwise in statesmanship.” Beyond politics, that’s an exceptional concept and a worthy approach to many facilities topics. Even more to the point this month, it’s also been said that without a weather-tight roof, everything beneath is in jeopardy. When you think about making an emergency shelter, the very first thing you build is a roof to provide protection from sun, rain, and snow. It only follows, then, that with a permanent building, the construction and function of the overhead protection is the first line of defense for the people, property, and equipment beneath. As the roof is often above the line of sight, it can be an easy system to overlook until it’s already failed and you’re staring at other damage that must be repaired along with replacing the roof. On top of all that, roofs appear to be deceptively simple because there are no “moving parts.” Mr. Lowell would certainly agree. So this time we’re going to look at some roofing systems and some simple steps to match the right product with your application.

Elemental forces

Depending on where camp is located, climate and weather should affect your choice of roofing materials and how they’re installed. Often the appropriate standards for your area have already been set by the regional or state building code including wind speed ratings, fire resistance, and even resistance to impacts.

Wind

The building codes contain pretty detailed design wind speeds by region. In some areas, there is sufficient historical data that the information is provided in tables by city. In most regions, though, design wind speeds are broadly shown on maps. There, you can see that the highest wind speeds expected are along the ocean coasts with some pockets of high winds inland. Most inland areas have a 90-mph design up to 130 mph along the coasts. These areas bear the brunt of tropical wind forces, so how the materials are made, plus how they are attached to the building, plays an enormous role in how “wind resistant” the roofing is. For example, many asphalt-type architectural shingles can be rated for either 90- or 130-mph winds simply by adding two nails per shingle (from four to six). Similarly for many other products, the wind resistance is enhanced by using more aggressive fastening systems. The manufacturer is best able to provide the specific code-compliant techniques and materials to achieve the wind resistance that you desire.

Fire

Here’s a double whammy: Some areas of the country are subject to fast-moving fires driven by high winds. In areas such as the northwest Great Plains and the high deserts of California, Nevada, and Arizona, strong winds can carry a wildfire spark for miles. Not long ago, wooden slab (“shake”) roofs of cedar or redwood were common in northern California in particular. But after a series of spectacular, devastating fires, the roofing industry was forced to seek an alternative to the highly flammable “sheets of tinder” on thousands of structures. You may be surprised to learn that modern “common” asphalt composite shingles sold in the U.S. are largelynon-combustible, meaning that despite having a high asphalt content (asphalt is made from petroleum), there are other materials present that resist fire from an outside source (such as the spark we discussed earlier). And finally, other roofing products like slate, terra cotta, and metal are inherently nonflammable.

Ice

And what about ice? I’m not referring to the ice that accumulates on the eaves (“ice damming” was the subject of a column some years back), but to hail. Until we moved to Montana, I’d never imagined that hail could be a real threat to much of anything. Remarkable hail in my native Pennsylvania was pea-sized. Here in the northern plains, though, “remarkable” is the size of a tennis ball (2 ¾ inches). So despite my lack of experience with this phenomenon, the insurance industry invested millions of dollars to devise two standard testing procedures for roofing products to resist the impact of hail. Both test systems classify products from one to four, with four being the most resistant to impact damage. One test uses steel spheres dropped from up to 20 feet; the other shoots ice balls from an air gun to simulate the impact speed. Interestingly, the first test (UL 2218) requires two impacts on the same spot without visibly compromising the material front or back, where the second test (FM 4473) only examines a single impact. Given this very significant difference in the testing procedures, you can see that although both may assign a “Class 4 impact resistance,” the rating represents very different performance from one system to the other.

You may be wondering how much this sort of additional protection might cost. During a recent residential roofing project, it cost about $1,500 more to install a UL Class 4 system over a Class 1 for 37 square (one square is 100 square feet), or about $2.50 / square foot (materials and labor). The insurance premium reduction (for the new Class 4 roof ) will pay for the added cost in less than ten years, and the installed product has a 50-year warranty. At my house, that is money in the bank.

Potential Additional Costs 

“Extra! Extra! Read all about it!” What about the extras? Some unscrupulous roofers may charge more for certain roofing-related services and installations, but really they shouldn’t be extra because they’re not optional. Some of these may surprise you if you don’t get them settled before the job starts.

It’s not unheard of to reshingle a roof without removing the one that’s there already. I’ve seen camps where there were as many as four distinct layers of shingles on a single building. Despite the claim that “that’s the way we’ve always done it,” it’s a lousy idea for a bunch of reasons. First is that most shingle manufacturers won’t warranty shingles with other shingles beneath. Shingles need to be nailed into plywood, not into other shingles. The built-up layers will hold heat and cause the asphalt binders to deteriorate very quickly, and leaks will quickly return too. And finally, the roof trusses or rafters are only intended to resist a certain amount of weight. Anyone who has ever lugged packs of shingles knows how heavy each one is, and layer after of layer of old roofing just adds weight that can overload the supporting roof structure. Where winter snow adds even more load, having multiple layers of shingles is just asking for trouble and collapse. Building codes universally prohibit more than two layers of shingles. Most require stripping the roof to the deck for inspection and replacement of the plywood as necessary. So even where “camp can do the work and no inspector will ever know,” the smart route is to never ever put more than two layers on any building.

But what’s to be done with the stuff that’s being stripped off? A contractor who intends to do the job right will have included a dumpster in the quote. A “short cut” contractor may offer that as an extra again, as if that was optional, because getting rid of roof demolition debris can be a difficult and expensive proposition. Asphalt shingles don’t burn easily and release pretty toxic chemicals in their smoke when they smolder. Burying them on your site is lousy housekeeping and a long-term liability. Proper disposal means hauling them to a licensed landfill and paying the landfill fee.

One often overlooked element is the stripped nails. An aggressive worker can fling spent roofing nails a long way from the worksite where they can settle in lawns, shrubbery, or driveway areas to be picked up by tires or bare feet. An unscrupulous contractor might tell you they’re all up without having looked and expect to be paid in full because the job is “done.” Save yourself the hassle and grief and discuss your expectations before the job begins. Ask how the contractor will limit the mess (like tarps at the roof drip line), control how far debris is spread (again, tarps and sometimes garbage chutes into a dumpster), and what equipment is used to ensure that all of the nails are recovered (magnets and sweepers). Take notes and then watch to make sure the procedures and tools he lists are all used. Don’t make the final payment until you are satisfied that the job is completely picked up at the end and that your site is safe for you, your staff, and your guests.

We began with a quote from James Russell Lowell, and it seems only right that we close with one from him as well. He wrote, “The foolish and the dead alone never change their opinions.” This time we looked at several aspects of roofing materials, products, and projects that may well run counter to “the way that we’ve always done it” at your facility. Camps are often steeped in tradition and history but, where facilities are concerned, those old ways may not be the best ways to get the most out of your physical plant dollars. Roofing systems are no exception. New materials available at the nearby home store may provide faster return on your investment and longer service life than the same old way.

Rick Stryker, is a professional engineer and facilities director in Montana with a passion for camps and conference centers. He would gladly receive your comments, thoughts, and column topic suggestions at rstryker@reagan.com.