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Seven Ways to Guarantee a Perfect(ly Bad) New Roof

There is an estimated 13.2 billion square feet of commercial roofing in the United States. Most roofs have an average expected life of between 10 and 15 years. This means that approximately 1 billion square feet of roofing will need replacement this year. Looked at another way, there is an 8 percent chance that the roof over your head, or the one over your tenant’s head, will need to be replaced this year.

With costs of roof replacement running as high as they are, you have the right to expect a good job. Unfortunately, there is no easy or simple way to ensure that your new roof will be a good one. One thing is sure, however. If you follow the seven easy steps listed below, we can almost certainly guarantee that you will get a poor roof.

1. Always choose the lowest bid.

One roof is pretty much the same as another. Let price be your sole criterion for choosing both the type of roof that you have installed and the contractor who installs it.

2. Always choose the highest bid.

For those who disagree with Step #1 above, there is an alternative. If you always have to pay for what you get, then it follows that you always get what you pay for. You can always assume that choosing the highest bid will automatically guarantee that you get the best roof.

3. Don’t write a specification.

Writing a specification takes time and costs money. If you must have a specification, get the contractor to write it. He knows what he can do most cheaply, and he may even be able to use leftover materials from another job to save you even more money.

4. Don’t waste time stripping off the old roof.

Demolition, cartage, and dump fees are costly. Avoid these costs by simply installing the new roof directly over the old roof. That old, rough, leaky, water-saturated roof makes a great substrate for a new roof. This will probably void your warranty, but you can save more money by not bothering with a warranty at all.

5. Save money on supervision.

Reduce supervision costs to zero by not having any supervision. You’ve spent $500,000 on a new roof. That’s a lot of money. Why spend an additional ½ percent merely to ensure that the job is done right? You don’t have a specification anyway, so what’s considered right is a subjective evaluation.

6. Don’t read the warranty.

If you did go to the extra expense of obtaining a warranty, be sure that you don’t read it. As the contractor will tell you, the gist of the warranty is that you are guaranteed not to have any problems for the life of the roof and if you do have problems, he will speedily and cheerfully remedy them at no expense to you.

7. Take that final step.

Someday soon after your new roof has been completed, go up on it just at dusk (better do this before it rains). Stand on your roof and think of all the money you saved. Wait until the first star dimly appears in the east—and make a wish.


Although the previous section is written tongue in cheek, a roof is one of the most expensive components in a building to replace. Unlike other building components such as HVAC units whose replacement can be phased in over a number of years, a roof is usually replaced all at one time. Therefore, this large expenditure must be borne in one year. This makes the decision to replace a roof a difficult one for building owners and managers. The temptation is to postpone the inevitable for one more year.

A roof can be nursed along year after year, but this is likely to prove to be a false economy. The decisions of when to replace a roof and what type of roof to install are business decisions. These decisions may be easier to make, however, if a new roof is considered an economic asset rather than a liability.

A new roof can be an asset to the overall value of a property in both the short and long terms. If an owner is planning to sell a building in the short term, a new roof will increase the purchase price or, rather, prevent it from decreasing. A roof that has exceeded its useful life will be considered to be a deferred maintenance item by a due diligence team. And, if any component of the building is discovered to suffer from deferred maintenance, this will raise uncomfortable questions about the maintenance of the other components.

In the long term it makes economic sense to replace a roof earlier rather than later. If the life of a roof is extended much beyond its useful life, maintenance costs are likely to increase beyond prorated replacement costs. There is also the danger that water penetration (some of which may not even be noticed) will cause damage to the underlying structure or other building components. The reduction in insulation value of wet insulation and the resulting increases in heating and cooling costs are other factors that contribute to making roof replacement a good economic decision. Finally, the liability of a major failure must be considered.

In summary, it almost always makes good economic sense to replace a roof when it has reached the end of its useful life. The expected useful life of a roof is reasonably predictable, so its replacement can be planned for and reserves set aside to pay the cost. With careful planning your new roof will be an asset to your building.

Criterium Engineers has inspected over 50 million square feet of commercial roofing in the past six months. We are the nation’s oldest engineering firm specializing in building inspection, diagnostic consulting, and due diligence services. To discuss roofs or other building concerns, contact Criterium Engineers at the address below.

Volume 11, Number 2

November 2000

Copyright © 2000

The Engineering Advisor is intended to enhance your knowledge of technical issues relating to buildings.  For additional information on any subject, please feel free to call us.  Our commitment is to provide you with timely, accurate information.