By Steven P. Bentz, P.E., RRC
Published in the November 2009 issue of Today’s Facility Manager
When managing facilities in a campus setting—where every building could potentially be a different age, type of construction, and different condition—facility managers (fms) will find that determining which structure will be repaired first is a critical decision. This decision can be complicated further by the criticality of the building, complexity of needed repairs, cost of the project, available budget dollars, the prominence of top floor occupants, and, in many cases, the level of inconvenience that would be caused by a leak.
Rather than letting the squeaky wheel get the grease, fms should decide where to spend money based on unbiased evaluations that ensure defendable and justifiable decisions are made in the best interests of the organization. In this manner, they can take the effort already being expended (e.g., roof maintenance inspections or simple drain clearance) and use it in deciding which roofs to fix when.
With some training and a few important guidelines, fms and their staff members can employ a basic methodology to characterize roof conditions effectively and extend service life. This type of methodology is designed to help fms set up consistent inspection practices that are repeatable, objective, and able to define existing conditions accurately.
A 10 factor prioritization methodology provides an effective and streamlined system in order to determine how to get the most for available capital dollars each year. This approach is well suited to campus settings where multiple buildings must be evaluated; however, the method can also be used for individual buildings, if desired.
The Prioritization Methodology
The prioritization methodology includes: documentation of the existing roof inventory by building; creation of a ranking system for roof inventory based on existing conditions; scheduling of the roof areas for repairs or replacements based on priority (as well as appropriate roof repairs and/or replacements); and ongoing management of roof inventory.
Within this program, evaluations of roof systems are based on 10 factors which are quantified by in-house staff to provide the basis for prioritization. The quantification or scoring should be able to be performed by trained personnel with minimal roofing experience; in-house roofing specialists are not required.
Each factor is ranked on a comparative scale from one to 10 (one being a low score and 10 being a high score). The individual scores for each of the 10 factors are then added together to develop an overall score for the roof, which is then used to develop a prioritization for the repairs or replacements in an objective manner. The factors within the Roofing Prioritization Schema are as follows:
- Age of existing roof system
- Roof criticality (use of building)
- Susceptibility to damage/roof traffic
- Membrane condition
- Flashing condition
- Attachment type/problems
- Slope and drainage
- Constructability (or difficulty)
- Leak history
Implementing The Factors
At several campus type facilities, these factors were used to rank multiple buildings by scoring each roof section. The scores were determined by minimally trained field personnel and then compared to the opinions of Registered Roof Professionals. Typically, scores below average were considered a priority for replacement, while scores in the 90th percentile indicated roofs that were recently installed or in good condition.
When comparing the roof rankings within a campus setting, fms can determine the necessary maintenance activities to keep their roofs in serviceable condition—defined by scoring above average but less than the 90th percentile—from deteriorating further. Fms can also determine when to fund the replacement of roofs that are on the verge of failure—those with scores below average. (See sidebar for a sample roof inventory list.)
This relatively simple system that captures critical roof inventory information (including all original construction documents, warranties, maintenance manuals, and inspection reports) is a highly effective way to manage roof inventory of a campus. Larger database systems tend to require many inputs, while one that can be readily maintained by minimally trained personnel will typically be updated more frequently after semi-annual roof walkthroughs, which are part of many maintenance programs already.
Identifying Repairs And Replacements
Appropriate roofing repairs are subject to the roofing material, supplier, and available contractors. While the key to good roofing repairs is to use a contractor with an established record with the manufacturer, experience and training in standard repair procedures and processes, and a history of performing repairs in the field, the key to maximizing a return on investment (ROI) is to have in-house staff members learn and understand the repair process so they can identify repairs more effectively in the future.
A critical part of the process is identifying which roof or roof section should be repaired in a timely manner. Regular inspections are typically conducted as part of a campus facility maintenance plan. But what can be difficult to quantify is a comparison between different types of roof systems and the degree of deficiencies in the systems that can be corrected early in the life cycle.
When regular inspections identify a repair item, should it be corrected immediately or deferred? Is the defect something that can be repaired? Or is the defect systemic of a widespread issue with a given roof? If the inspections reveal an issue that could be design related or systemic, or that may require a specialized repair, the use of a qualified roofing design professional to evaluate and design the appropriate repair may be necessary. However, it might be possible to have in-house staff determine that a roof is worn out and needs to be replaced.
If the need for replacement arises, care should be taken to select the appropriate roof assembly for the structural conditions present. In commercial and institutional applications for flat or low slope roofs, the four most widely used roofing materials are single-ply thermoset (EPDM or EPDT), single-ply thermoplastic (PVC, TPO, or Hypalon), modified bitumen (APP or SBS), and built-up with traditional bitumen (hot mop or coal tar) and felts. For sloped roofs, the most widely used products in commercial and institutional applications are asphaltic or polymer based shingles, metal roof panels, clay tile, and natural materials (slates, granites, etc.).
Each product has strengths and limitations in terms of installation, durability, ease of repair, and other factors critical to long-term life cycle costs. Selecting the appropriate product will contribute greatly to a low cost roof over a building life cycle. Knowing how to compare the defects and life cycles of various roofs allows for comparison across a campus.
Closing The Loop
The 10 factor prioritization methodology allows for unbiased decision making based on the factors and repeatable, comparable survey results. In order to implement this ranking system, some training of the facility’s maintenance staff is necessary (along with developing and updating a roof inventory database). Once the steps are laid out, annual inspections and re-ranking can be performed by on-site personnel to help direct funding to the right projects at the right time.
Bentz ([email protected]) is a senior professional at Facility Engineering Associates in Fairfax, VA. He is a graduate of Penn State University’s five-year ABET accredited professional degree program in Architectural Engineering, with an emphasis on structural systems and added specialization in building enclosure science and design. A Registered Professional Engineer in six states and a Registered Roof Consultant, Bentz is an active member of the Sealant, Waterproofing, and Restoration Institute (SWRI), ASTM International, and National Roofing Contractors Association (NRCA).
How do you track the condition of your roofing inventory? Send an e-mail to [email protected]