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frequently asked questions
A. Minimum R-Value, the thinnest point in a tapered system occurs at only one location in each system. Average R-Value is the measure half-way between the minimum and maximum r-value in the tapered system. Average R-Value is the quantity that should be used to calculate real heat transfer through the entire tapered system.
2. Q. What is compressive strength as it relates to Polystyrene Insulation?
A. Compressive strength is the weight, usually expressed in pounds per square inch, required to compress polystyrene to 90% of its original thickness.
3. Q. What is a Cricket?
A. A cricket or saddle is a pyramidal diamond shaped device used to divert water around an obstruction such as a skylight, HVAC unit, chimney, etc; or to divert water along a parapet wall to the drain sump or through-wall scupper.
4. Q. Would you recommend building a cricket out of wood?
A. No; wooden over-build crickets can trap moisture, even when vented. Trapped water vapor will encourage dry rot, damaging the roof system, roof substrate, and possibly the building structure. Crickets constructed of foam insulation leave no void where moisture can collect.
5. Q. What is the industry standard for slope on a commercial roof?
A. 1/4” per foot slope has been the minimum industry standard for some time. It is now a code requirement in most locations.
6. Q. Does Tapered Design do site visits / roof walks?
A. Yes; see our page Analyze for more information
7. Q. Can tapered systems be priced by the square?
A. No. Due to the many variations of drainage designs, insulation thicknesses, and many other factors, tapered insulation systems cannot be priced by the roofing square.
8. Q. What material is tapered insulation manufactured in?
A. The 4 main types of tapered insulation are Polyisocyanurate (ISO), Perlite, Expanded Polystyrene (EPS), and Extruded Polystyrene (XPS)
9. Q. What is a multiple layer cricket?
A. Typically a cricket is formed of one layer of tapered insulation. On occasion, one or more layers/tapered systems must be employed to counter a steep roof slope. (example: 2 layers of 1/2" per foot slope cricket = a 1" per foot slope cricket.)
10. Q. How much time is required for standing water to be considered a pond?
A. 48 hours when sunlight is present.