Velociflex is not a product, but a roofing system that is designed to offer high wind resistance and optimum performance, while reducing the labor required for other more traditional roofing systems. Membrane product types available for designing a Velociflex system include APP and SBS membrane offerings (2022-Velociflex-Brochure-web.pdf (polyglass.us)
The Velociflex system allows for quick installation of membranes to increase the time and labor it takes to handle and install a Velociflex system. There are numerous options and performance levels when designing and installing a Velociflex system, some of which we will cover in the following information.
There are a variety of challenges and issues is the design of a high wind resistant roofing system. Among these considerations are location; coastal, mountains, flat terrain and each of these offers many considerations. For example, if it is a coastal exposure, how far is it from the coastline, how protected in the roof from surrounding buildings, how tall are the roof parapet walls. Many of these considerations carry-over onto other locations such as near mountains, such as how protected the roof is, it is on a hillside, how tall are the parapet walls, these can all be a significant factor. Proper roof system design must consider all factors in its design. Know all the project facts and consider each in any design.
The Velociflex Systems features two main membrane components, the base membrane and the capsheet. The base sheet of the typical Velociflex system is the handling and layout of this base membrane. With its wider side laps at 5”, mechanical fasteners (deck screws and metal insulation plates) are placed at the desired spacing, the side lap is then torched together and sealed. This allows for a fast and efficient installation.
As the base membrane with mechanical fasteners and sealed seams serves as the means for the roof to resist wind forces, the cap sheet’s focus is to provide additional weatherproofing, a wearing surface and appearance. Cap sheets options for Velociflex are heat-fused, fully bonded in a cold adhesive and self-adhered.
Ultimate wind performance is not just a function of the base membrane, the choice of cap sheet and method of installation can impact wind ratings of the completed system. The highest performance options will be those that utilize a heat-fused cap sheet, with systems tested for high wind protection up to -270 psf (lbs per sq ft). Just a few examples of the many system options are shown below.
Torch Cap Sheet option up to -270 psf
Base Membrane: Elastoflex S6 HP which is an SBS membrane with an enhanced polyester mat that complies with ASTM D6164, Type II, fastened 6” o.c. within the heat-fused 5” seams.
Cap Sheet: *Polyfresko G SBS which is an SBS membrane with a traditional polyester mat that complies with ASTM D6164, Type 1 that is fully heat-fused to the base membrane.
*Polyfresko G is a highly reflective membrane with an initial SRI of 96 and 83 for 3 years weathered.
Cold-Adhesive Cap Sheet option up to -165 psf
Base Membrane: Elastoflex S6 HP which is an SBS membrane with an enhanced polyester mat that complies with ASTM D6164, Type II, fastened 12” o.c. within the heat-fused 5” seams.
Cap Sheet: Elastoflex S6 G which is an SBS membrane with a traditional polyester mat that complies with ASTM D6164, Type 1 that is fully bonded with a cold-adhesive to the base membrane.
Self-Adhered Cap Sheet Option up to -105 psf
Base Membrane: Elastoflex S6 HP which is an SBS membrane with an enhanced polyester mat that complies with ASTM D6164, Type II, fastened 18” o.c. within the heat-fused 5” seams.
Cap Sheet: Elastoflex SA P FR which is an SBS membrane with a specialized polyester mat that complies with ASTM D6164, Type 1 that is fully bonded with our self-adhesive technology to the base membrane.
The self-adhered cap sheet allows for a quick and reliable installation while still achieving a high-performance roof system. Self-Adhered technology offers unique performance advantages. Third-party peel test showed that the Polyglass self-adhered side laps are superior to all other application methods. 146% stronger than the cold process. 8% stronger than a torched lap, and 2.5% stronger than a hot-mopped SBS roofing. In addition, the granule-free end lap, which equates to 75% less labor to complete versus a traditional end lap installation.
Wind Forces and Wind Pressure
Wind is a major topic in many coastal and wind-prone areas, but what is wind speed and wind forces and how do they impact a roof.
The speed at which wind blows is very evident when directly exposed to it. Think about how even a 10 mph wind moves a normal adult around when standing in the path of the wind. Without something to interrupt the wind’s impact such as trees, buildings or walls, even relatively minor wind speeds can feel impactful.
Wind and wind speed particularly create forces or pressures upon the various surfaces they come in contact with, this creates wind pressures. Depending on the surface, flat or curved, tall or short impacts the wind pressure created, be it positive pressure or negative pressure. The impact depends on the surfaces and conditions, for example if wind blows against a building with open doors and windows the wind force inside are positive and push upward against the bottom of the roof deck, whereas the wind forces blowing over the walls at the roof level create lift and what is negative pressure literally sucking items upward.
Wind pressures impact all things it impacts be it trees, houses or large commercial structures. The impact of these wind pressures and the size and configuration of any building must be an important factor in design if you wish the building not be badly damaged by wind forces.
Velociflex – A Result of Products and Performance Working Together
Polyglass understands the value of dependability and performance offering various options within the Velociflex System. Our continuous efforts on innovation and product performance, means we are always finding ways to add value to our products and customer experience. Velociflex is just one of the steps that Polyglass can solve your high wind roofing needs be it in hurricane-prone locations or other higher wind-prone locations.
Polyglass has a team of experts to help you choose the best Velociflex System for your project. To learn more about the Velociflex System or any other many membrane offerings reach out to our team members or look to our website at www.polyglass.us.