Up on the Roof
- By Janet Wiens
- March 1st, 2006
Snow and cold, wind and rain, heat and sun. Roofs take extensive abuse. The weather in different parts of the country presents unique challenges when it comes to selecting and maintaining these all-important building components.
In the Northeast
The cold and snow experienced by colleges and universities located in the northeast require attention to the details both during design and for long-term maintenance. Flat and sloped roofs differ when it comes to materials but share some common areas. Getting started on the right foot is critical.
It’s vital that you look at the details when you’re working with your roof designer and contractor, says Fred Stoddard, building construction engineer for the University of Maine.You must fully explain all details, including intersections and terminations, to get the best price up front and to minimize problems in the future.
It must be noted that flat roofs aren’t really flat, according to Stoddard. He says that all roofs have some level of slope to drain so that water doesn’t pond on the roof.
When it comes to materials for flat roofs, Stoddard says that coal-tar pitch was used years ago. The Environmental Protection Agency forced its replacement with coal-tar bitumen because of the toxicity in coal-tar pitch.
The University of Maine uses an extensive amount of ethylene-propylene-diene-terpolymer, or EPDM, a fully adhered roofing system that works well and is very economical.We try to do major roofing projects in warmer weather, but sometimes we have to do work when it’s very cold, says Stoddard. EDPM is more forgiving when it’s applied in colder weather compared to some other products.
For shingled roofs, he recommends heavyweight architectural style shingles, which help to seal the roof. An elastameric membrane underneath the shingles at the drip edge and at least six ft. within the inside wall of the building helps prevent leakage from ice damns.
All roofs at the university are inspected once or twice a year, which is probably true at the majority of colleges and universities. Repairs are made as necessary in order to hopefully avoid major undertakings when snow and cold weather must be battled.
Dealing With Wind and Rain
Bill Rork is the new maintenance manager for National Management Resources Corp. at Palm Beach Atlantic University, Palm Beach, Fla. Through the years, he’s gained extensive experience working with roofs, and the potential winds in Florida due to hurricanes are a major consideration when it comes to this building system. Wind uplift in south Florida can be very high, and the codes are extremely strict, he says. Each roofing system must receive a Notice of Acceptance in order to be used in our part of the country.
For example, Rork says that foam systems — where foam is sprayed on top of the roof and coated — is a cost-effective solution that can slope to drain well. However, he says that this isn’t a good choice in Florida because of the potentially high winds.
Vinyl roofs, like a pool liner, are good when it comes to dealing with ponding water and are a cost-effective solution. Rork says that a 10- to 15-year life expectancy for a vinyl roof can be realized with proper maintenance.
Coal tar is still the best alternative for flat roofs, in my opinion, Rork states. Because of our hot weather, small tears will self-seal, and the system can withstand some ponding water. These systems also have a life of 20 to 30 years, which is important when it comes to the bottom line.
Rork advises that moisture surveys should be done every three to five years in his part of the country. The process involves using infrared or nuclear-testing equipment to detect any moisture in the insulation under the roof. Insulation that gets wet doesn’t fully dry again, and this can cause problems. The surveys help detect moisture, and affected materials can be replaced before larger problems develop.
It’s a good idea for colleges and universities to set aside three cents per square foot annually for roof maintenance, according to Rork. Yearly maintenance should involve cleaning and checking all drains and all lap and expansion joints. Areas around anything that penetrates the roof, such as vents or fans, must be very carefully inspected for problems.
Sun and Heat
Las Vegas is great when it comes to tourism, but the sunny and hot weather in this part of the country puts roofs to the test.
Ken Hughes is a construction project coordinator for the University of Nevada Las Vegas (UNLV) and is heavily involved with maintaining the University’s roofs. We established a roof shop three years ago, he says. Our goal is to be very proactive when it comes to roof maintenance and repairs in order to avoid major problems and repairs as much as possible.
UNLV uses mainly Energy Star rated products, including solar white PVC membranes, for roofs. We have 136 buildings, most with low-slope, commercial-type applications, under our care, Hughes says. Only two of our buildings have tile roofs. The Energy Star products help to lower our HVAC operating costs, especially during the summer. Our goal is to operate our buildings as efficiently as possible, and the Energy Star products help us to operate more economically.
Hughes says that when reroofing occurs, rigid insulation is added to the roof assembly to increase the R value, which further helps to decrease operating costs.
He strongly advocates regular inspections. UNLV currently inspects roofs semi-annually but will go to quarterly inspections in the near future. The university’s facility database is used to help track word orders, queries and reoccurring problems on buildings.