slope region accordingly the present teachings realize the advantage of increased stability and or tension applied to the substrate when fenestration assembly 300 is in an assembled state though fig2 shows the slope of slope region 204 at an approximately 45 u00b0 angle relative to adjacent tape bed area 208 the present teachings contemplate the use of any angle so long as the slope creates a region proximate to slope region 204 that is sufficient to receive a corresponding nipple of a tensioner preferably the angle of slope region 204 is a value that is between about 30 u00b0 and about 60 u00b0 relative to adjacent tape bed area 208 as shown in fig2 viewing area 206 spans the length of one side of base frame 200 viewing area 206 may be a region of base frame 200 that when the fenestration assembly is assembled and installed is an outer surface of the fenestration assembly in other words this may be the portion of the assembly that is visible to an observer inside a building envelope in alternate embodiments of the present arrangements however a backside of the tensioner is the portion of the assembly that is visible to an observer inside a building envelope in other words in such embodiments a back side of a tensioner represents a viewing area endcap 202 is designed to cap base frame 200 at a first end though the embodiment of.