Glossary

Roof Slope

Roof slope is described as inches of rise for each foot of run; e.g. 3/12 is 3 inches of elevation for each 12 inches of horizontal run. Many roofing products state a minimum slope required for proper installation, so products with a minimum slope requirement GREATER than your selected value will be eliminated from the search results. Also, many products with a minimum slope requirement will have additional installation requirements, such as a layer or layers of underlayment, at or near the minimum slope stated.

Maximum Weight

Roofing product weight is usually stated in terms of installed pounds per square, which is 100 square feet.

Minimum Fire Rating

Classified fire ratings are dependent on the roofing system components as well as the deck type and slope. This attribute indicates the product is eligible to be used in a roofing system classified for external fire exposure, but the fire rating is not applicable unless all material and installation conditions have been met.

Minimum Rated Wind Speed

Many roofing products have been tested and rated by the manufacturer for the maximum wind speed the roofing can withstand. Special installation requirements must typically be met to achieve the published wind speed rating. All products so rated that have ratings equal to or GREATER than the value selected will be included in the search results.

Minimum Wind Warranty Length

Term of wind warranty coverage, generally from time of purchase or installation. Warranty term may be longer when included in a roofing system guarantee or through an addendum.

Base Material

For steep slope composition roofing, base material defines its reinforcement. For many types of commercial/low slope roofing, base material typically defines polymer type. For other roofing types, such as metal, the base material should be self-evident.

Minimum Thickness

Mils are thousandths of an inch. 1 inch equals 1,000 mils. CAUTION: Many proofing products, such as some asphalt shingles, do not include thickness in the product data, so selecting this value will eliminate such products from the search results.

Minimum Width

For shingles, width is the long, or horizontal dimension. For sheet products, width is the roll length.

Design

Designs included are most common types available for products other than sheet or fluid-applied materials.

Minimum Exposure

For overlapping roofing (typically steep slope types), exposure is the amount of material exposed to view when the roofing is installed.

Finish

Materials with inherent finish, such as copper or stainless steel, are typically not categorized by the finish attribute, which is primarily applicable to paints and other applied finishes.

Minimum R-Value

Most roofing products do not include data on thermal resistance, since the values are typically quite small. Selecting this attribute will limit results to products such as insulated metal panels and spayed foam roofing, which typically include thermal resistance among the published attributes.

Layer

Selecting this attribute will effectively limit the results to products making up various types of multi-layer bituminous roofing systems.

Application

Selecting this attribute will limit results to various types of single-ply systems.

Minimum Reflectivity

Most roofing products do not include specific data on solar reflectivity, either because the values are low or because reflectivity varies significantly due to color or texture differences. Those products with published reflectivity data frequently do not include aged values, so the only values included in the Nominpensas database are initial values. For more complete data on roofing reflectivity and emissivity, consult manufacturer's product data or the CRRC Rated Products Directory at https://coolroofs.org/directory.

Minimum Tensile Strength

Expressed in pounds per square inch, tensile strength is a measure of the product's ability to withstand a pulling, or tensile force. In the Nominpensas database, data on this attribute is limited to green roof components, roll roofing, and fluid-applied roofing. Manufacturers do not all measure this property using the same test method, so comparison of manufacturers' actual product data is important to assure the products are being measured in the same way or by compatible methods.

Minimum Compressive Strength

Expressed in pounds per square inch, compressive strength is a measure of the product's ability to withstand a pushing, or compressive force. In the Nominpensas database, data on this attribute is limited to green roof components and sprayed polyurethane foam roofing, Manufacturers do not all measure this property using the same test method, so comparison of manufacturers' actual product data is important to assure the products are being measured in the same way or by compatible methods.

Minimum Elongation at Break

Elongation at break is a measure of the amount of stretching that can occur before the product ruptures or otherwise fails.

Minimum Puncture Resistance

This attribute is measured in pounds of force required to penetrate the product. Manufacturers do not all measure this property using the same test method, so comparison of manufacturers' actual product data is important to assure the products are being measured in the same way or by compatible methods. In the Nominpensas database, data on this attribute is limited to green roof components.

Minimum Water Retention

Measured in gallons of water per square foot of roof area, this attribute is relevant only to green roof components, where retaining water is an important trait.

Minimum Water Capacity

This attribute, expressed as a percentage, is the water holding capacity of the growing medium used in green roofing. Normally, the desirable percentage will fall between 30% and 65%.

Minimum Organic Content

This attribute, expressed as pounds per gallon of soil, is applicable only to green roof growing media. Soil used on a green roof is typiclly a blend of lightweight aggregates, sand, and organic material need for plant growth. The amount of organic material needed will depend upon the type of planting contemplated and the required water capacity in the growing medium.

Minimum Solids

Expressed as a percentage, this attribute is the ratio of solids to the total volume of fluid-applied coatings for foamed roofing.

Minimum Flow Rate

This attribute, which applies only to green roof drainage elements, is a measure of the volume of water that can flow per minute per square foot of roofing.

Maximum Permeability

Permeability in roofing is resistance to the flow of water vapor, measured in perms. Products with ratings of one perm or less are effectively water vapor barriers or retarders. Higher perm ratings do not mean the material is less water resistant -- only that water vapor can more readily pass through. In Nominpensas, this attribute relates only to coated foamed roofing.

Minimum Density

Density of polyurethane foam, measured in pounds per cubic foot, may be inversely related to thermal resistance. Denser foam therefore is more resistant to outside loads, such as workmen walking on the roof, but may have slightly less thermal resistance because less air is included.

Minimum Wall Thickness

Measured in mils, the wall thickness of green roof tray modules can be assumed to be directly related to strength and durability.

Minimum Length

Wood shingles and shakes can be used only on steep slope roofs, and the length required will be related to roof slope and minimum exposure desired.

Minimum Grade

Wood shingles and shakes are graded by different organizations according to multiple criteria. These include color consistency, clearness from knotholes and other flaws, and whether split or sawn. When comparing products from different manufacturers, it is important to verify that grading standards use similar criteria.

Minimum Flexural Strength