Roofs

• By Pieter van der Have
• 06/01/14

Not long ago, I wrote a piece for this column that identified underground utility systems as the aspect of a project’s design and construction that is often neglected by professional designers and owners alike. It is now time for us to look up, all the way, to the top of our buildings.

Let’s be honest: for a number of facility managers, the roofing system is one of those building liabilities that are not at the top of the list of attention-grabbers — until something goes wrong, that is. Until then, we just know that it is there, and mysteriously doing its job — we hope.

What’s Up There?

Most college campuses have flat or nearly flat roofs on their buildings. I know of a few that pleasantly contradict this observation. UC-Boulder comes to mind almost immediately, with only a few misguided (?) exceptions to its generally Tuscan flavor. Flat roofs offer maintenance and durability challenges that we might not see with properly designed roofs sporting a slope greater than 2:12.

What is the function of a roof? It is threefold: to keep the weather out, to insulate against heat loss/gain and to help provide fire protection. It is thus important that the right system is selected (designed) and installed, and that FM performs the appropriate inspection and maintenance functions for that particular location. What does a roofing system need to do to meet the first criterion: to keep the weather out? Clearly, that depends on the location.

If you live in a hot, dry and sunny area, you will need to make sure that a roofing product is installed that can resist the sun’s UV rays. Note that it is not at all uncommon for warranties to vary based on calculations related to the intensity of the sun. Some, but not all, single-ply products perform well in this type of environment.

In an area where the days are hot and the nights are 30° cooler, you may want to consider a product that performs in a manner consistent with the demands of serious expansion and contraction while also emphasizing insulation. You will want to make sure that proper flashings are installed at parapets and around any penetrations, of which there should be as few as possible.

Water, Water Everywhere

Trying to assure proper performance of flat roofs in extremely wet climates can also be challenging. Are roof drains located in the lowest points of the roof deck? (Common sense naively tells us that it should always be this way!) Some jurisdictions require overflow or auxiliary roof drains. These should be located within a specified proximity to the main drains, and higher. Additionally, scuppers may be desirable, but only if they are installed at the right location and not lower than the overflow drain. Remember that water is heavy (more than 62 pounds per cubic foot), and that a six-inch wading pool on your roof might be too much for the roof’s support structure. One final note about scuppers: Make sure that, when they come into play, they don’t drain onto the exterior skin of the building.

Flat roofs (especially BUR) often come standard with some sort of ballast, primarily present to counteract the effect of the sun’s UV rays. That particular solution works well for that specific challenge. However, I recently learned of a situation where hurricaneforce winds whipped the gravel ballast over the edge of the roof, causing significant damage to that building’s windows as well as adjacent ones. A different protective system, such as a reflective coating, might have made for a better solution.

(Don’t) Walk This Way

If the roof is a parking place for the building’s HVAC equipment, odds are that maintenance technicians are going to need to gain access to that equipment by walking on the roof. Good practice suggests that a lightweight paving system installed on the roofing membrane, when installed in the right locations and when accompanied by proper training, will minimize pedestrian traffic in areas where it shouldn’t occur. It may also help avoid turning the roof into an unsightly and even dangerous storage area for spare supplies.

Early in my career, I became aware of a leaky roof repair technique that was, and is, highly ineffective and wrong. To simply dump five-gallon buckets of roofing tar on suspected leaks does not usually solve the problem, and will often aggravate the problem by applying it where the leak isn’t.

These few words are not intended to be “An Idiot’s Guide to Roofing Maintenance.” They are intended to emphasize that roofs are important, critical systems that demand proper design and installation, continuous inspections and constant mitigation, plus tender loving care. Otherwise, your roof might flush itself onto the technology center or precious books collections, inevitably located right below a wannabe leak.

This article originally appeared in the issue of .