Frequently Asked Questions

How do I maintain my single-ply roof?

Answer: All low slope roofs should be inspected at least twice per year and after any major storm. Look at the perimeters to determine if there is any loose metal or fasteners and pay particular attention to flashings around penetrations. Make sure they are tight and undamaged. Remove debris and ensure that all drains are open. Note any changes from the past inspection, and if questions arise, consult the contractor that installed the roof or a Registered Roof Consultant.

For more information on roofing maintenance you can purchase the SPRI/NRCA document Manual of Roof Inspection, Maintenance, and Emergency Repair for Existing Single Ply Roofing Systems from the National Roofing Contractors Association at

Are sheet membranes available in colors?

Answer: Sheet membranes come in black and white and a large variety of standard or custom colors on request. You can find more detail on availability of colors by contacting a manufacturer directly. Manufacturers can be found in the SPRI Member Directory.

How do I cover my patio deck with a sheet membrane?

Answer: Most SPRI Members provide a variety of materials utilized for and in waterproof deck systems. You can get more information by viewing the SPRI Member Directory and following the links to the members of SPRI that supply membranes.

What wind ratings are available for sheet membranes?

Answer: Sheet membranes are rated in pounds per square foot of uplift resistance. Factory Mutual is one of the more widely recognized agencies that measure uplift pressure. Factory Mutual uplift pressures are reported from 60 pounds per square foot to 999 pounds per square foot uplift resistance (FM 1-60 to FM 1-999). You can get more detail on specific product’s uplift resistance by searching through the SPRI Member Companies in the Member Directory.

How do I determine the surface roughness and exposure category (wind) for a building?

Answer:  Surface Roughness and Exposure category information is available from ASCE 7-16 which is produced by The American Society of Civil Engineers. It is available for purchase here. The information is also available in Chapter 16 of the International Building Codes.

“Simple” descriptions have been prepared for Surface Roughness and Exposure categories. They are as follows are:

B. Urban and Suburban areas, wooded areas, or other terrain with closely spaced obstructions having the size of single-family dwellings or larger.

C. Open terrain with scattered obstructions having a height generally less than 30 ft.

D. Flat, unobstructed areas and water surfaces.

Can I reuse the existing insulation on the roof when I re-cover/re-roof?

Answer: The re-use or re-cover of building products, including insulation, is typically an economic choice. Recent technology advances and product developments will not be present in previously installed products. The owner/owner’s representative must compare these product “enhancements” to the economic advantages of re-using or re-covering the existing products. Individual manufacturers should be consulted regarding specific criteria for re-use and re-cover of existing building products.

Insulation looses very little R-value after the first five years; therefore, older dry insulation is likely to maintain a significant portion of its original R-value. SPRI research has shown that damp insulation can dry to the interior of buildings if there are no barriers between the insulation and the building. (Typically, wet roofs on metal decks with no vapor barrier will dry, whereas insulation over concrete decks has no opportunity to dry to the interior.) Before re-covering over existing insulation, it is advisable to make core cuts to determine the characteristics of the existing system, primarily to determine if there is a vapor barrier in the system that would prevent drying. It is advisable to conduct moisture surveys to determine if wet insulation exists and where it is located. Most roofs will not be entirely wet. The wet insulation can be removed from areas where the system will not be able to dry, and be replaced with new insulation. Again, consult the individual manufacturer regarding specific criteria for reuse and re-cover of existing building products.

Do you have installation specifications for sheet membrane systems?

Answer:  SPRI membrane manufacturer members have guide specifications for their products available online. You can connect with specific manufacturers in the SPRI Member Directory.

Can you recommend a roofing contractor in my area?

Answer: You can find the SPRI Member manufacturers by referring to the SPRI Member Directory. Many manufacturers have information about finding a contractor listed on their website. You can also contact the National Roofing Contractors Association at Clicking on “Find a Contractor” will provide a list of contractors in your area that participate in the national organization.

How long will sheet membrane roofs last?

Answer: Due to the variety of conditions and circumstances that exist, no guarantee of length of life of any roofing product can be made. However, SPRI has represented successful sheet membrane manufacturer’s for over 20 years. Quality roof membranes, properly installed and maintained are still performing today.

Can I adhere Modified Bitumen membrane directly to a wood deck?

Answer: Most suppliers of Modified Bitumen sheet membrane recommend the use of a mechanically attached base sheet over a wood deck. Consult the Modified Bitumen membrane supplier in the SPRI Member Directory for further information.

Does an edge system need to be a complete system to meet the requirements of ES-1, or can an ES-1 designed/tested component (such as a cleat) be added to an untested component (such as a cover) to produce an ES-1 compliant system?

Answer: ES-1 requires that fascia and copings be tested to RE-2 and RE-3 respectively. In both tests, the load is applied to the metal that provides the surface to the wind. Therefore, these systems need to be tested as a complete assembly.

Does the IBC code requirement that perimeter edge metal be tested per ANSI/SPRI ES-1 mean that I must use pre-engineered metal edge products?

Answer: The NRCA has had some specific coping and fascia products ES-1 tested, and NRCA members that are sub-listed with the NRCA can fabricate those ES-1 tested products. However, simply copying the NRCA products does not mean you have produced an ES-1 tested product. The sub-listed contractors are provided detailed fabrication information and they are audited by the NRCA’s testing agency to assure that the products they produce are equal to those that have been tested.

Is ES-1 only a design standard, meaning that any organization can manufacture an ES-1 compliant edge simply by using an ES-1 design? Or, is ES-1 a manufacturing standard, meaning that the organization which manufactures the edge system needs to demonstrate that the system meets ES-1 as tested by an independent agency?

Answer:  ES-1 has been revised and is now referenced as ANSI/SPRI/FM 4435/ES-1 2017,Test Standard for Edge Systems Used with Low Slope Roofing Systems. Section 1504.5 of the International Building Code requires that edge securement be tested per the RE-1, RE-2 and RE-3 procedures described in this method. ANSI/SPRI ES-1 testing should be performed on systems as manufactured by a given fabricator because the fabrication method can influence the test results.

Do all sizes and gauges of roof edge products need to be tested or can it be assumed that smaller sizes and heavier gauges of an identical product produced by the same fabricator will provide equal or better resistance ratings?

Answer: All sizes and gauges do not need to be tested. The generally accepted position of those doing ES-1 testing is that a product has an equal resistance to that of a tested product if it is (all 5 must be met):

  • the same design and configuration
  • produced by the same fabricator
  • manufactured from the same material
  • an equal or heavier gauge
  • an equal or smaller size
Is SPF considered to be a membrane as the term is used in 1504.5 and does an edge system used with a SPF need to be tested according to ES-1?

Section 1504.5 identifies low-slope built-up, single-ply and modified bitumen membrane systems that are to be tested.