Developing a roof asset management program

Why are roofs managed? There are three commonly accepted reasons: keep out precipitation; augment the heating, ventilating, and air conditioning (HVAC) system; and protect the owner's investment. The earliest shed roof prevented precipitation from entering the building, and this task is still the primary goal of all steep and low-sloped roofs.

07/01/2001


Why are roofs managed? There are three commonly accepted reasons: keep out precipitation; augment the heating, ventilating, and air conditioning (HVAC) system; and protect the owner's investment.

The earliest shed roof prevented precipitation from entering the building, and this task is still the primary goal of all steep and low-sloped roofs. Since the 1970s oil embargo, energy savings have become much more important and properly insulating the roof and providing reflective surfaces are now popular. The 1980s and 1990s brought mergers, acquisitions, and downsizing into the marketplace. Now, all building components must be optimized to achieve maximum longevity and economic life.

In this era of shrinking budgets and added responsibility, it is important to realize that the roof system is a financial asset that must be managed to extend its service life, while providing the protection the building requires and minimizing the inconvenience and expense of any downtime. For many years, HVAC and electrical systems have been managed for exactly the same reasons. The financial impact of losing the HVAC or electrical system has always been well known to the plant engineer. The financial impact of premature roof failure is now also apparent.

Depending on the complexity of the project, roof replacement costs vary from $6%%MDASSML%%$20/sq ft. The inconvenience and disruption of a roof replacement job are an enormous strain on a plant operation that is already stressed to maintain efficiency and control costs.

In the past, budgets were more liberal and money could be "found" for capital improvements on a regular basis. Little or no attention was given to the roof unless it leaked. Only then would someone be dispatched to fix the immediate problem. However, at that point, water was already in the roof system and the insulation's thermal value was already compromised.

Any decrease in thermal resistance increases heating and cooling energy demands. In some single-ply roofing systems, water adversely effects seam performance. In built-up roofs, water can start blisters that accelerate the deterioration of the membrane, which leads to premature replacement.

Water also corrodes insulation and membrane fasteners and reduces wind uplift resistance. Water can corrode steel roof decks, which adds additional expense to repair or replace the damage and jeopardizes the structural integrity of the building.

In combination with certain insulation, water greatly accelerates the decay of a steel deck causing extensive and very costly emergency replacements. The insulation's dimensional stability is compromised, and it turns into a "mush like" consistency. The membrane loses its attachment to mushy insulation and is subject to wind blowoff.

A roof asset management program prevents small initial problems such as these from becoming large ones.

Develop a plan

A roof asset management program is proactive. Initially, a full history, survey, and inventory of each roof is completed and the information is entered into a database.

This step is critical to the success of the program. An experienced roof asset manager must perform or directly supervise this phase. Any defects found during the initial survey must be remedied. Periodic inspections are made to observe how the roof is aging. Corrective measures are immediately taken to address small deficiencies which can be performed at a relatively low cost.

Periodic inspections are typically scheduled in the spring and fall of each year. The spring inspection is probably the most important because it allows time to assemble a repair list, bid the work, and complete the job during better weather. The fall inspection is used to review the spring repair work and any other small items that may have occurred between the two.

Some flexibility exists regarding who conducts these inspections. The spring inspections should be performed by a qualified individual experienced with the nuances of the plant's particular roof system and the repair techniques for the observed defects. Typically, these inspections are visual with some minor probing if regular maintenance has been employed.

Every 3%%MDASSML%%5 yr a roof moisture scan should be conducted to determine if any water is finding its way into the system. Sometimes the walls, perimeter parapet walls, or moisture vapor from within the building contribute to the accumulation of moisture in the roof system.

The moisture scan is vital to an effective roof asset management program. It provides a major insight into the condition within the roof system and allows the opportunity to make a small repair for a low price before it becomes a large problem with a big tag.

The fall inspection can be made by the same outside expert who performed the spring check or, if staff size and existing work demands permit, someone from within the organization. The fall inspection is mostly a visual review of that year's repair work, along with a report and update of the roof's database.

These inspection and repair costs are anticipated and budgeted annually. Repairs are done in the better weather with improved results, as opposed to waiting until a leak appears in bad weather and scrambling to find someone to fix the problem at premium rates.

Roof asset management programs are customized to fit the owner's needs. Some owners require the full support of the consultant, which includes implementing the program, surveys with reports, bids, and contractor coordination. Other owners require only partial assistance. The facility's resources establish the level of involvement for the consultant dependent on knowledge and experience of staff personnel.

What drives the need for roof asset management? The continuous demands to protect the building, its interior, and its operations from the outside elements and their damaging effects are the constant considerations.

How can the company economically afford the seemingly "additional" cost associated with the program? In reality, these are not additional costs, but are essential requirements to improve roof system performance and reduce the long-term costs of a low-sloped roof system. Life cycle costs are the guide to show how a maintenance program extends the service life and lowers overall expenses of the roofing system.

Life cycle costs

Life cycle costing of buildings and systems in accordance with ASTM E 917-93 provides a means to measure two or more methods over a given period of time (usually 20 yr). The measurement is in terms of the "present value" of money, which reveals today's value of all dollars that will be spent over the given time period for repairs, replacement, inspections, interior damage, and maintenance. Taxes, depreciation, and the discount rate for money are also incorporated into the life cycle cost calculations.

The aggregate sum of each year's total net expense present value is the total present value life cycle cost for comparison with the other methods under consideration.

Compare the numbers

The spreadsheets on the previous pages (presented by Luther Mock, RRC, Martin-Riley-Mock, Fort Wayne, IN, at an RIEI roof asset management seminar) demonstrate life cycle costs for two approaches to roof management. The spreadsheets are in accordance with ASTM E 917-93 and are for a tax-paying entity and a 20-yr time period.

Approach 1 has no formal maintenance program. The roof is repaired only when it leaks and is replaced at the end of the 10th year. Approach 2 has an initial survey, visual surveys twice a year, preventive action repairs, leak repairs, moisture scans every 5 yr, and the roof is replaced at the end of the 20th yr.

The calculations reveal that Approach 1 has a total present value life cycle cost of $141,901, while approach 2 is $104,817.

This example represents a saving of $37,084 in present value using Approach 2, which includes spending over $43,000 in the roof management program and preventive action repairs during the 20th yr.

Experience indicates that the lack of an asset management program significantly shortens the service life of a roof system by as much as half. This reduced service life is devastating to any building owner's chance of an average return on investment for their roof system.

In this case, the total present value life cycle cost is reduced 26% ($37,084 divided by $141,901) when a roof asset management program is employed versus no maintenance plan. When jobs such as fixing small holes, patching splits, and repairing seams are done on a timely basis, they contain costs, prevent much larger expenditures, and extend the service life years at a time. If the same repair is ignored until it is a crisis, the repair cost to extend the service life the same amount is multiplied several times.

The complete roof asset management program begins with proper selection and design of the system. The key to a successful maintenance program is longevity, which drives down the life cycle costs. It puts off the very large capital expense of roof replacement.

Accepted roofing practice is that a four-ply built-up roof lasts longer than a three-ply, a three-ply modified bitumen roof lasts longer than a two-ply, and a 60-mil reinforced EPDM membrane lasts longer than a 45-mil unreinforced EPDM membrane — all conditions being equal.

In each example, the former is clearly the better quality and higher initial cost. But life cycle costs support the decision to purchase the better quality (higher cost) roof system to ensure the longer service life and higher return on investment in almost all cases. Inspection and maintenance costs are not trivial but are essential for the program to work. Proper selection and design of the system are the very first steps that should be taken to maximize your opportunity for a successful roof maintenance program.

The support and commitment from all personnel who have input are required if any program is going to succeed. A roof asset management program is no different. It needs the CEO, CFO, head of engineering, and individuals who service the roof to be on board and realize these small efforts have the leverage to add years to a roof's service life. It is part of a continuous process.

Sound design, quality materials, proper installation, and timely maintenance are the keys to longevity and true low costs.

Edited by Ron Holzhauer, Managing Editor

Key concepts

Roofs guard against the environment, help control energy costs, and protect the owner's investment.

A proactive management program includes an initial roof survey, regular inspections, and prompt repairs.

Life cycle costing shows how a maintenance program extends the roof's service life and lowers overall expenses.



Typical roof problems

Changing cycles of rain, heat, cold, wind, and UV radiation, along with expansion/contraction, environmental pollutants, and foot traffic, are continually attacking the roof surface. Because these destructive factors are never ending, the roof should undergo a thorough inspection twice a year, typically in the spring and fall. Any problems detected should be immediately repaired.

These photos illustrate a number of problems likely to be encountered.

Mineral surfaced base flashing has slid down from behind the counter flashing.

Single-ply base flashing has split at the base of the flue stack allowing moisture to enter the plant.

Parapet stone coping has moved and opened a 3/8-in. wide joint to a 1-1/4-in. space. Water enters the parapet wall and into the building through this opening.

Single-ply coping joint cover has split and allows water to enter the system.

A 2-5/8-in. high ridge in a mineral surfaced cap sheet has lost its granule protection and splits occurred in the top.

Single-ply membrane has split at the gravel stop fascia, allowing moisture to migrate inside.

Blisters in this built-up roof accelerate with aging and decrease the service life.



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