A Roof’s Design is VERY Important


It's a busy season for building custom homes in Iowa. Unfortunately, many of these new, beautiful homes have flawed roof plans. They may look incredible, but without the proper design, roofs are susceptible to damage, which could cost homeowners thousands of dollars to repair. If you're buidling a new home in the Ankeny, Huxley, or Des Moines area or considering installing a new roof on your current home, consider the following factors very carefully. 

How Shingles Are Applied

There are two ways to apply shingles to a roof. One way is to lay new shingles on top of old (existing) shingles. The other way is to first tear off the existing shingles, and then lay down the new ones. While the first option is less expensive, it could cause major problems down the road. Your initial thought may be that layering shingles will offer your home additional protection. The truth is, however, that there are many reasons that layering shingles this way is considered bad practice.

Disadvantages to laying new shingles on top of old ones:

  • A second layer of shingles will add a lot more weight to your roof and may compromise your home’s structure.
  • Manufacturers' warranties often won’t cover shingles laid in this way because the new shingles are not able to lay flat and conform to the roof or each other properly. Instead, they will conform to the old shingles beneath them.
  • If shingles cannot conform properly, then they will not seal properly, which means they may not be able to stand against winds as they are guaranteed.  They could more easily be blown off, necessitating further  repairs.
  • Your roofing contractor would not be able to inspect the roofing deck for current damage or moisture problems.

Advantages of tearing off old shingles first and then laying down new ones:

  • Any defects in the roofing deck will be revealed when the old shingles are torn off. Defects will then be able to be repaired before new shingles are applied.
  • You will be able to have waterproofing underlayment installed underneath the new shingles.
  • Your contractor will be able to see if your roof or attic has any condensation or moisture problems that need to be dealt with.
  • A good ventilation system will be able to be installed, if needed.
  • Your roof will look smoother and more expertly finished.


A proper ventilation system should be installed beneath the roof deck. This will reduce the buildup of heat, moisture, and condensation in your attic, as well as prevent snow and rain infiltration and ice dam buildup. A good ventilation system keeps the attic temperature closer to the outside temperature by creating a continuous and balanced flow of air, removing humidity and drawing in cool, dry air.

Water Flow

Make sure your roofing contractor considers how water flows off of a roof during heavy rains. If this is not considered thoroughly in the initial design and installation stages, your roof could be susceptible to water intrusion, costing thousands of dollars in damage to the interior of a brand new home.


By installing underlayment, you are giving your roof an extra layer of protection. It will be placed between the wood decking and shingles. This protects your home against heavy or wind-driven rains and ice dams.


Installing a new roof is a big investment. Don’t cut corners just to save a little money now when you may regret it later. Take a good look at your options and carefully consider what is best for your home, both now and years down the road. If you need assistance in making a decision or would like more information about roofing in general or Hedrick Construction’s roofing, installation, or repair services, feel free to contact us anytime!

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