Bricks, Masonry, Asphalt and Concrete - cracking in mortar of glass block window bank

not sure if this thread belongs here or at doors and windows. i just took off the 1/4 round moldings from one of my 3 banks of glass block windows, 3'x8'. glass blocks are 8"x8". i see that they are set with a mortar completely except for the very top edge of the top row. is this the way it's supposed to be? also the middle row, vertically, has some minor cracks in the mortar. what is the best and recommended kind of caulking to use in this mortar type application? the craftsman who did this 72 sq. ft. of glass block windows did a super job. they still look great after 30+ yrs. a true craftsman!

I can't answer your question, but can tell you where to geta good answer.
Look in the yp under glass block and visit one or two. I built a glass block bar 10 years ago and did they were extremely helpful! Their prices on block was competitive with the big box stores.

Glass block windows are usually built with a soft joint at the top. Just like any other windows or doors, the loads must be carried by the surrounding structure.

Dick

what is a soft joint? there is just a little thin strip of insulation loosely on the top of these windows. can i caulk the top gap with a high quality silicone or does it need to be left as is. if i caulk with a good flexible silicone, will i be doing more harm than good? i'm redoing the walls where these windows reside. so is fixing the cracks in the mortar with some sealant now a good longterm solution? i want it to be right before i put the new moldings around these windows.

Caulking the top is entirely proper. It prevents the load from being carried by the window when the wood studs around the window shrink.

It is good practice for all windows, but not as critical for glass block because of the high strength of the glass block.

Just use a quality caulk.

Dick