When it comes to replacing the roof on your home, there are many decisions to be made. Most of the decisions turn on the answer to the question: “what are my goals for this property?”
Do you intend to keep the property for many years? Will this roof be an investment into the property that you intend for it to appreciate with the property?
Do you intend to sell the property? Is replacing this roof merely a necessary evil that you can no longer avoid, but you’re motivated to replace at the lowest possible cost? Are you an investor trying to flip the home? Are you working for a bank and just trying to get rid of the property?
The answers to the question of “what are my goals for this property?” will greatly influence the decisions regarding what type of performance you are looking to attain from this new roof. Is this the last time you ever want to have a new roof installed on your home? Is your home in an area where the climatic conditions demand a higher level of performance from your roofing materials, such as the oceanfront in Virginia Beach, perhaps? Is aesthetic value, high performance and peace of mind all valued goals that you are taking into account while deciding on your roofing choices.
For more roofing info, check here: Selecting shingles for Quality and Price , a new roof in the neighborhood, how to find a roof leak, should you replace your leaking slate roof?
On the other hand, if your goal is just to replace the roof for as inexpensively as possible, you may not be concerned with the aesthetic value that some of the more designer roof materials can achieve, you’re probably not placing much value on performance of the roofing materials and the goal is a straightforward return on investment on a commodity purchase: budget driven selections.
Once you have determined the answer the first question:
1. What are my goals for this property?
You know must make choices on two more questions, regarding the scope of work (what is actually going to be done) and specification (how it’s going to be done) for the roof installation. Those two questions are:
1. How are we going to prepare the roof before the installation of the roofing material?
2. What kind of roofing material will we use? (asphalt shingles, slate, tile, shakes , etc)
NOTICE THAT THE CHOICE OF ROOFING MATERIAL IS #2. Most people ignore question #1: “Preparation” and only consider the type of roofing material (To their peril)
Since asphalt shingles are the most commonly used roofing material on residential roofs in the Hampton Roads Area: Williamsburg, Yorktown, Newport News, Hampton, Norfolk, Virginia Beach, Chesapeake, Suffolk – I will focus on shingles for the remainder of our discussion here today.
Why is preparation so important? The performance of a roof, as far as watertightness, has less to do with the shingles as it does with cannot be seen from the surface of the roof. By that I mean, a roof is far more likely to leak in the flashings than it is in the open field of the shingles.
Of all the roof leaks I look at each year for homeowners (100’s every year: it is literally “raining indoors” in Hampton Roads), less than 1% of the leaks on shingle roofs are in the “field” of the shingles. By rule, shingle roofs leak where they stop, start and change directions.
Most common leak on a shingle roof: vent pipe collar. It’s not even close percentage-wise. Plumbing vent pipes protrude the roofs of almost every home. They are typically round and made out of copper, cast iron or most recently PVC. The neoprene gasket that is used to create the watertight seal around the plumbing vent pipe is made from the same material as the windshield wipers on your car. It dries out in the sun, cracks and splits and almost “invites” water to enter the home. 
Typically, they last about 7-10 years. Therefore, if you purchase a roof with a shingle that is intended to last 30 years, how many times during the lifetime of the roof do you think you will have to replace the pipe collars on the roof because they are leaking again? Are there longer term solutions for pipe collars, if you want to avoid having to spend money on roof maintenance once a decade? Sure there are, but isn’t this a decision that should be made when you are deciding “how we are going to prepare the roof before the shingles are installed”? Certainly your goals for the property will decide if this is a roofing detail that you want to invest more money into or not.
What’s a roof flashing? Does this sounds like some kind of perv? Not exactly. It is the second most common leak source after pipe collars. Wherever the shingles stop or start against a vertical obstruction on the roof, whether its a wall with brick or siding or it’s a chimney or skylights, there will be pieces of sheet metal (typically aluminum or copper) that are placed in the transition of the horizontal plane of the shingles and the vertical plane of the obstruction. These pieces of metal are called flashing. They are often installed incorrectly and leak. They are often re-used from the original roof to the new roof – as you may expect the new nails don’t go into the old nail holes – this commonly leads to leaks. Chimney leaks, skylight leaks, dormer leaks, etc. 99% of the time are flashing leaks. Replacing all the flashings while installing a new roof can significantly increase the cost of a roof installation, but it is critical to the long term performance of the roof. Your goals for the property will very much influence whether you are motivated to make this preparation detail a priority or not.
What other preparation choices should be taken into consideration? What about underlayment? What is felt paper? Should we completely remove all of the felt of the original roof (add labor cost)? Should we use a heavier felt this time (add material cost)? What about a fiberglass reinforced felt underlayment (add material cost)? What is your cost/benefit and return on investment for each? Such questions can only be answered in the context of your goals for the property.
Another important underlayment consideration that must be addressed involves the question: “do we think it is prudent to invest in additional protection in leak prone areas such as valleys, eaves (ice dam prone), and other protrusions?” A material that has become very popular for this purpose is a self-sealing waterproof underlayment like Winterguard, also commonly referred to as “Ice & Water Shield”. It has it’s place and function and can be a valuable part of roof preparation. Sadly, many less than competent roofing contractors use it as a panacea to compensate for improper roofing practices elsewhere on the roof. It will NOT prevent leaks that are caused by improper installation of flashing or the shingles themselves.
When trying to decide on question #1: How are we going to prepare the roof before the installation of the roofing material? It may be helpful to learn that there are two choices of standards to prepare the roof to:
1. The Building Code – typically a minimal standard. “The worst job that can be legally done.” Most codes will allow a second layer of shingles to be installed on top of the original roofing. If the choice is made to remove the original roofing material, the codes do not require underlayment, will allow all flashings to be re-used and have minimal ventilation requirements. A roof installed to this standard will be normally be the lowest cost option available because of the labor and material cost savings. However, a homeowner should not expect superior long term performance from a roof installed to a building code standard. Roof failures prior to shingles reaching their warranted lifespans are common, due to the fact that the shingles themselves are not the source of the failure, but rather there exists a problem with a preparation roof detail such as flashing, etc.
2. The Manufacturer’s Recommended Specifications – A detailed preparation standard based on established “best practices” for the industry, typically set forth in the manufacturer’s specification manual. Certainteed’s Master Shingle Applicator has become the standard for the shingle industry. Described by Certainteed: The Master Shingle Applicator™ program provides education in every aspect of shingle installation techniques, and the approved procedures for installing all CertainTeed shingles. The program covers topics such as workmanship, roof systems, estimating, flashing, ventilation, and product installation instructions. A roof installed to this standard should be expected to perform to length of time the shingles are warranted for, but should also be expected to cost significantly more to install than a “Building Code” roof- for the exact same type of shingles.
At this point you may be saying to yourself, “WHO HAS TIME FOR ALL THIS???” I hear you! You don’t make a living by educating yourself on roofing. FEAR NOT! 
I would suggest hiring someone who does, so that you can focus your time on what you DO make a living doing! Hire a professional contractor who is certified by a reputable shingle manufacturer. Focus less on the color of the shingle you want on your roof and more on selecting the right contractor to look out for your best interests so that you get a project you are happy with and they are proud of! We’ve discussed contractor selection here: http://www.jimhicks.com/how-to-make-a-wise-contractor-selection/