Studs on the "flat"

Hey all -- Could someone comment on these two wall assemblies? The one on the right is from the SAE site. It has a shared, wide plate and an STC of 54 (with insulation). The one on the left is my creation, and has a shared 2x4" plate and the studs "on the flat" (as they say around here). Assume that it is also insulated. Would the STC of the second assembly be close to the 54 of the first? Is there benefit to this, or would it actually lose out because there is more wood in contact with the drywall? Guesses and/or facts are welcome! Thanks, Andy

Might result in a floppier wall, which would be considered more ideal for isolation but inferior for strength. There may be code restrictions that prohibit that type of construction. Those look like staggered stud configurations to me... Not ideal from an isolation standpoint. Separate frames is better, for sure. --Keith :mrgreen:

sharward wrote:

Might result in a floppier wall, which would be considered more ideal for isolation but inferior for strength. There may be code restrictions that prohibit that type of construction. Those look like staggered stud configurations to me... Not ideal from an isolation standpoint. Separate frames is better, for sure. --Keith :mrgreen:

Thanks Keith. On-the-flat construction (in a line, not staggered) is typically done (around here) to save space between closets and such, but usually in small doses. I know that separate frames would be far better, but I can't afford the space for that. I'm trying to lose as little space on the wall assemblies as possible, because I'm not starting out with much to begin with. I'd also like to avoid using RC on the walls, to save that money, and staggered studs (as shown in the lefthand picture, anyway), is slightly better than RC. Another question: Am I shooting myself in the foot worrying about the walls, while planning to use a single solid-core (slab) door? What's the STC on a well-sealed door? - Andy

Somewhere around STC 32 (with a dip to 25 in the range of 600 hZ) for a MDF core, flat slab door 1-3/4" (exterior door) with no additional build-up - actual mileage will be less, this figure would be if the door were actually caulked on both sides... Steve