How to Measure the Jamb Width?
MEASURE THE JAMB WIDTH
Jamb width is the measurement of the wall thickness that the door unit will be fitting into, this includes any sheetrock or sheathing/siding that is on the outside as well. This is one of the most important things you will need to know when replacing a door unit. If your jamb is too small, the framing or rough opening in the wall may be exposed and if you jamb is too large then it will need to be trimmed and fitted to the wall. If your jamb is not the right size it may also cause problems like the door being unable to close or have a tight close ensuring protection from the outside elements or create a draft.