This is not a true product topic but I am tapping into the collective experience of those who post to 4specs.com.
It never ceases to amaze me that what I have seen done on the job site, no one seems to know how it was accomplished.
We do highrise condos with concrete frame. The concrete floor slabs receive a skim coat of plaster or some such product, painted white. The designers do not want a joint exposed to view at the head of the wall. We toured a finished condo in Vancouver BC with the the wall to slab interfaces with the look and feel of a typical gypsum board to gypsum board inside corner.
Someone out there (Anne W.) must have done this before for rated and nonrated partitions. I am looking for details, details, details.
There are two conditions to consider: partitions interior of the unit and those partitions that separate units. The partitions separating units require, movement, fire, and acoustic characteristics and require partition head details that carry fire and acoustic ratings (and esthetic concerns you mentioned). This can be tricky, but take a look at UL System Nos. HW-D-0003, HW-D-0016, and HW-S-0009 for examples of a gyp board partition to flat slab concrete. (Also look at the bottom detail BW-S-0001 and those following 2, 3, 4, etc.)
Thanks and we are aware of the 2 conditions you highlighted. The head of wall details will have to satisfy fire, smoke, and acoustic requirements. What I need are details on how to achieve the no-joint look at the end of the day. I will check out your suggestions.
In a cost is no object universe you could hang the wall from the upper floor slab and conceal a nested double sill track behind an appropriately expensive base trim.
The key problem that I see is concrete creep of the elevated floor slabs. The head-of-wall conditions will need to accommodate that slow, downward movement. If the gypsum board is tight against the concrete deck, it will eventually crack or crush over time.
Wayne, how old was the building you looked at? If it’s new, I bet if you toured the same building a few years from now it won’t look so nice.
Building we walked through is new, nearing occupancy. I had thought about Ralphs suggestion before. It will add a crown molding look that will be nicer than cracked drywall mud or white sealant or post painted sealant. I think it has a merit. Requires a good technicain to cut and form the inside/outside mitered corners. I think I may use this as the basis for design.
Thanks to all the usual suspects for replying. I will go forward with Firetrack.