In traditional stucco work, is there a distinction between control joints and expansion joints ?

Yes. but very little.

Yes. Expansion joints were made for two reasons-one to control cracking due to expansion and one to provide a stopping point for the application of materials. A control joint provides a stopping point or a break in applying materials.

Heavy dense materials like stucco, concrete etc. expand and contract with humidity and temperature. Lightweight materials, such as EIFS don't really expand at all, but the joint is used as a stopping point. The synthetic finishes are more unforgiving in leaving joins. The joints here are just control joints, or a place to stop.

In the old days, before anyone thought of expansion joints, big houses sometimes had decorative bands to provide a place to take a break.

In EIFS or synthetic "one-coat" stucco the control joints just give the mechanic a stopping point, even though they are referred to as expansion joints, they are really control joints, or a place to stop.

If you have followed my site, you may have seen that I don't like control joints because I think they are ugly, and completely unnecessary. Old houses didn't have control joints, and we mainly work on old houses.

I have heard that these joints are necessary. We work in old neighborhoods where the stucco houses are in good shape, and have no control joints. However, we work on fairly new houses with control joints that are rotting and falling apart.

Step flashing and kick out flashing

A view of a double "V" expansion joint.

without Counter flashing chimney or dormer will leak

A true expansion joint is made in two pieces, like this expansion joint from Flannery Trim.