The Surprising Impacts of More Roof Insulation

June 17, 2022

It’s time for a tear-off and reroof. Not only has the performance of roofing materials continued to improve over the years, but so too has the need for energy efficiency. The new roof system you install won’t be the same as what was there before. One of the most likely changes will be to the insulation.

Whether mandated by building code or recommended by a roofing professional, it’s likely the roofing system proposed will have two (or more) layers of insulation. “It is good roofing practice, and most consultants, architects, and FM approved systems call for it,” explains Jack Kenney, Vice President National Account Manager, D. C. Taylor Co., Cedar Rapids, IA.

There is an obvious benefit of higher R-value, but with added layers of insulation also come some surprising impacts to the roofing project that you may not have considered.

Better Efficiency

The larger the R-value, the greater the insulating capability. Right-sized insulation provides an R-value sufficient to limit the escape of heated and cooled indoor air, as well as prevent outside air from penetrating. When this happens, HVAC systems must compensate for the heating/cooling loss by operating more than necessary

Even how insulation is installed affects its energy efficiency. “When insulating, you want to avoid thermal short, which is a direct conduit of cold and hot. Use of staggered layers should be considered,” explains D. C. Taylor Co.’s Vice President National Account Manager Ben Fashimpaur.

More Materials, More Labor

Using two or more layers, doesn’t just mean purchasing more insulation; the attachment materials are different. “When it comes to fasteners, ¾ to 1 inch has to go through the metal deck, so you might be using a 7- or 8-inch fastener,” explains Mike Poorman, Project Manager, D. C. Taylor Co., Cedar Rapids, IA. It’s not just mechanically fastened systems that are impacted. With multiple plies of insulation over a concrete deck, more adhesive is used.

While you can expect an increase in cost for adhesive or fasteners, the biggest impact of materials is the space they take up. The more insulation you decide to install on the roof, the more that is delivered to the jobsite. Expect higher freight costs and the need for a larger staging area during the project. If the site is already heavily trafficked, make sure to schedule the deliveries so the semi-trucks bringing materials aren’t in the way. With added insulation, loading materials onto the roof is bound to take longer, as will the installation; expect to pay more in labor costs.

High Profile Problems

Adding insulation at a greater thickness may prove challenging if the roof is congested with piping and equipment. If you have HVAC systems and gas or electrical lines on the roof, those may need to be raised due to the added height of the roof system. “If you’ve got a doorway that comes out onto that roof, is the insulation too high for that threshold?” asks Poorman. Your roofing contractor will be able to identify solutions and strategies to deal with these challenges.

Time for a reroof? Call D. C. Taylor Co. today at 319.731.4118 to get your project on our schedule.

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