What to do with a stair to wall connection?

Hi folks, This question is also included within my main design/construction post ( http://www.johnlsayers.com/phpBB2/viewt ... highlight= ) currently sitting in the queue. However, builders are doing what builders do and I need to get ahead of this issue. The below picture (holy smokes I'l liking SketchUp) shows a cross section of the basement stairs, stair ledger and studio wall. The question is what can/should be done at the ledger/wall connection to minimize footfall noise translating from stair tread into the studio? Final tread material will be oak. Looking at the illustration on pg 77 of Rod's book I notice a mineral wool 'gasket' between the ceiling backer and blocking. Would this also be the tactic to employ in the stair/wall connection? Thanks much!

From the (no longer available) US Gypsum Sound Control Manual - "A similar situation occurs when a stairway is attached to a party wall. Often the stairway is built and installed before the gypsum panels. Attached directly to the partition studs, the stairway produces a sound path directly into the adjacent apartment. The occupants complain that "people are walking through the living room." Stairs should be supported independently to allow space between them and the partition for normal drywall treatment; or better, the stairway should be installed after the gypsum panels have been hung, taped and caulked (Figure 86)." Copy of Fig.86 below - I've attempted to contact USG's webmaster to see if this resource can be reinstated - but don't hold your breath... Steve I've not tried this, but would think that a layer of Celotex or similar soft board between stringers and drywall might further deaden any flanking.

Thanks so much Steve. I'll get this infor to the builders. re: the Celotex - Are you referring to Soundstopfiberboard or underlayment?

Sorry, too many things with that name these days - I was referring to the "acoustic ceiling" looking stuff - white, with a bunch of fissures/cracks in the surface. Although any of the softer, "regurgitated paper product" type boards would help. Most would look like crap without something else over the top though. Main thing is to NOT have the stair stringers directly attached, or nailed through to, the wall frame... Steve

Lee, Figure 10.14 shows you exactly what to do with the stairwell in that condition. Seeing as I was working with multiple layers of drywall - I indicated that the wall beneath the stairwell opening frame should be offset to allow for the installation of the 2 layers of drywall required for isolation - with the existing sheet of drywall lapping over and finishing that. Perhaps you should look at it again.......... Rod

Thanks Rod and Steve. I hadn't spent any time in the 'putting it together' chapter - thanks for the gentle kick in the pants :oops: . My builders are *very* excited about this information and in learning what it takes to make the room work for the intended purpose.