Building Management Hawaii - June/July 2012 - (Page 12)
What Drains Your Building?
Hurricane season is the time to check drainage—from drains and downspouts to scuppers and weep holes.
By Jeff Gowan
s hurricane season approaches, it’s a good time to gear up for semiannual rounds to ensure your properties are prepared from the top down. Keeping your building watertight—from the rooftop to the ground—means understanding the integration between the roofing assembly and drainage components. Being aware of the weak points will help you take the whole building envelope into consideration. Here are the top four roofing and drainage checkpoints for common problems: The majority of serious roof leaks are caused by slowed or failed drainage. Make sure the rooftop drains, downspouts and scuppers are clear at both the top as well as the bottom exit points, especially if there are trees in the area. Another cause for slow or failed drainage is additional screens installed over drains or at the bottom of downspouts (to keep rodents out). While well intentioned, they end up impeding the water flow. Also, keep an eye out for damaged and crumpled downspouts from vehicles backing into them. This can cause backed up gutters or high volumes of water channeled toward window frames or doors.
A 40-floor side view of the Franklin Towers in Salt Lake.
Buildings with internal gutters are notorious for flooding when drainage becomes an issue.
#2 Don’t Seal The Deal!
#1 Capping the Trap
It’s not uncommon to find that an attempt to fix one situation in fact causes another problem due to a misdiagnosis. Many times building maintenance crews are not familiar with the rooftop design and will try to apply caulking to keep water from getting in—but when applied in the wrong place, this actually keeps water from getting out. Another common mistake is sealing off design elements such as weep holes around a skylight, window frames or railings that are in fact designed with the assumption that water will get into the framework and needs an escape. DIY repairs on metal roofs are another commonly attempted fix where certain areas of the panels are sealed off that should not be, causing water buildup and migration into the building below. Caulking in itself is a maintenance item and should not be relied on as a long-term solution. With Hawaii’s rapidly growing sector of roof mounted solar electric systems, a common issue is photovoltaic (PV) installations that jeopardize the roofing system from successfully performing its watertight function. Improper materials and/or installation can lead to voided warranties and premature failure of the roof platform if not properly integrated. PV arrays usually require multiple penetrations to the roof system and should be
properly installed and waterproofed. PV systems also have the potential to cause ponding due to location and weight factors, thus proper material selection is crucial. A roof warranty requires upholding manufacturer’s specifications—one basic requirement of which is watertight penetrations (PV standoffs, vents, skylights, lead pipes, etc.). Items such as load, usage and proper waterproofing of the standoffs are crucial for long-term sustainable integration of the roof system. Simply caulking around a lag
#3 Watertight Penetrations
Franklin Towers, the tallest building in the Salt Lake area, had a failing membrane that was shrinking and pulling away from the walls. Carlisle thermoplastic polyolefin (TPO) retrofit roof membrane was both adhered and anchored over the building’s existing EPDM “rubber” membrane to address the rooftop’s susceptibility to high winds.
bolt will not ensure that water cannot intrude and improper installation is a common issue seen with shingle and tile roofs. PV systems are typically warranted to last 20 years, so installing the right materials for the proper roof platform is crucial for long-term sustainability.
#4 Don’t Short Circuit Your Savings
Short-term savings in “cheap” fixes for a small water moisture or ponding issue can grow into a big problem, headache and budget item. Relying on caulking to fix a problem is simply a temporary solution. It is a less than ideal quick-fix that needs to be continuously addressed, demanding
Table of Contents for the Digital Edition of Building Management Hawaii - June/July 2012
When the Winds Blow
Why Waterproof? Keep your building watertight & upright.
Get Watertight Water is the greatest solvent in the world ... keep your building dry.
What Drains Your Building?
Asbestos Exposed How to safely recover from mold and flood damage.
Water Leaks—from Bad to Worse
The Power of Paint
Life of Paint
It’s Best to Test A paint test can detect lead, and be the trick in finding a paint that will stick.
Movers & Shakers
Resource Guide: Waterproofing & Painting
Building Management Hawaii - June/July 2012