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What Is the U Value of My Low Slope Roof?

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Commercial roofs are complex systems with interdependent parts. Together, the layers of your commercial roof have a measurable U Value. U Value is the coefficient of transmission of heat through materials. It is the inverse of the more widely known R-Value, a measure of resistance to heat transmission. The U Value of your commercial low-slope roof directly affects your company’s energy bills. 

By the Numbers

U Value, having an inverse relationship to the widely accepted and coveted R-Value, suggests lower numbers are better. This is true. Consider a low-slope roof with R-19 insulation. The combined layers, insulation included, produce a U Value of U- 0.05, derived from 1/R (in this case, 1/19). 

We know R Value measures the resistance of heat flow into your building. U Value measures how much heat leaves your building. Our Florida fellow business owners may desire very high R Values, such as R-30, for their roofs. Here in New Hampshire, the lower the U Value, the more money you save heating your physical plant. 

Measuring Your Building’s U-Value

To get an accurate assessment of the U Value of your building’s low-slope roof, your local, trustworthy commercial roofer has several options available. One is to take a core sample, drilling through the layers of your roof to see its composition.  If you purchased the building from a previous owner, you may have no knowledge of the roof, its construction, repair, or upkeep.

Another method, if you are the original building occupant, is to study the roof warranty and architectural plans, then perform a roof inspection to see if the roof was completed according to specifications. 

A roof’s layers could be simple: deck, vapor barrier, rigid insulation, or single-ply membrane. A roof’s layers could be complex: deck, vapor barrier, insulation, built-up roofing, ballast, and more. 

New Hampshire Low-Slope Roofs

Beyond the obvious concerns of ice and snow on New Hampshire’s low-slope commercial roofs, U Value plays a key role in keeping your company’s energy costs down. Having a realistic measurement of your building’s U Value can help guide decisions about reflective coatings, re-roofing, adding insulation, and other economizing moves. 

To work with local experts in low-slope roofing, please contact us at J. Carnes & Son Roofing. We have the expertise to deal with R Values, U Values, and much more. We know low-slope roofing, and we are here to help save you money.