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Guide to Door Lite and Sidelite Inserts


Note: to see our selection of lites, visit our Door- and Side-Lite Section of Products

The surround insert in a door panel or sidelite is a full 3-piece component, consisting of exterior moulding, interior moulding (both of which make up the lite frame, or rim) and glass sandwich. Over time, usually due to heat absorption, many plastic door lite rims crack and need to be replaced.


When this happens, there are 2 options:


  1. 1) The entire surround component, glass and frame, can be replaced.
  2. 2) The glass frame can be replaced and original glass retained for reuse.

When replacing a surround, 4 measurements must be noted to order the correct replacement:


  1. 1) Tip-to-Tip: Basic width and height of outside edge of plastic rim

  2. 2) Glass Size: Basic height and width of glass within surround (not just visible glass); call size

  3. 3) Glass Thickness: Thickness of inslated glass unit (glass sandwich)
    • Typically either 1/2" or 1"

    • If only replacing frame but not glass, you need to purchase a frame requiring the same glass size and thickness or the surround will not fit in the cut-out properly.


  1. 4) Cut-Out Size: Basic height and width of cut-out in door or sidelite for surround
    • Typically between 1" and 1-1/4" bigger than glass size

This guide to door lite and sidelite inserts deals with Therma-Tru brand lites. We can sell these as full components with glass included or just the door lite rims -- no glass. Our stock currently consists of five standard; lite frames are white composite and glass is 1/2" thick and clear without embellishment. Frames are paintable, although we advise against painting frames dark colors, as dark colors can cause frame to absorb more heat and crack over time.


Standard sizes (call sizes) that we stock are listed below; all are in inches:


  • 8 x 36
  • 7 x 64
  • 20 x 36
  • 22 x 36
  • 20 x 64
  • 22 x 64

Note: Other sizes, frames and embellishments are available for special order upon request. All leaded glass surrounds come with glass thickness of 1"

For detailed installation instructions, see Replacing Glass Surrounds.

For video on removing Therma-Tru sidelites and door lites, see How to Remove Therma-Tru Door Lite and Sidelite Inserts