FAQ Knowledge Articles

Clad Ultimate Double Hung Round Top Picture - Next Generation (CUDHRTP-NG) and Clad Ultimate Double Hung Round Top Transom - Next Generation (CUDHRTT-NG) products have minimum springline height dimension limitations due to how the bottom rail connects to the stile and manufacturing safety concerns. 

Therefore, certain round top shapes which do not have a springline height dimension are not available in these product types (i.e. RT1, RT7-8, RT17-18, RT29, RT31-32,and RT42-43 shapes). 

Available Picture and Transom shapes for these product types include RT2, RT6, RT9-10, RT21-26, RT30, RT33-34, and RT45-46.

However, there are minimum springline height limitations depending on round top shape and product type. 

For CUDHRTP-NG units:
  • shapes with a continuous springline (i.e. RT2) have a minimum springline height of 4 55/64", and
  • shapes with a non-continuous springline (i.e. RT6) have a minimum springline height of 7 5/8". 
For CUDHRTT-NG units:  
  • shapes with a continuous springline have a minimum springline height of 3 23/32", and
  • shapes with a non-continuous springline have a minimum springline height of 6 1/2". 
The CUDHRTP-NG unit uses a taller bottom rail than the CUDHRTT-NG, per the Architectural Detail Manual.

For existing openings in which round top shapes are needed but not available in CUDHRTP-NG and CUDHRTT-NG, Marvin recommends CUCART product as an In-Sash alternative which is available in many of these shapes.  The CUCART daylight openings are unlikely to align with CUDH-NG product as these products are made with different frame and sash parts, but they are fairly close and accessories such as SDL bars can be aligned across these product types.