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mahatmacat1

mongo--pocket door sound insulation?

mahatmacat1
18 years ago

Hello, master-of-all-trades :) G'web is an amazing place and you seem to have knowledge in SO many categories--hope you don't mind my picking your brain here too...

We're putting a pocket door into our Master Bedroom as part of this master suite epic project you've been reading about on the bathrooms forum, and I was reading up here on various approaches to sound deadening. The pocket door frame is posing a challenge, since we can't do the alternating-stud/split 6" sill thing we've been doing for the other walls.

What would you recommend for insulating between the frame of a pocket door and the drywall? Is there something really nice and slim? We can only go with one layer of drywall, but we are having only a small jamb on the other side of the pocket (the side where the door extends to, not the side it tucks in on) before we jog inward, so we could pretty easily match thickness there if necessary. Here are some suggestions you made in another thread:

"There are the metal isolation channels that hold the drywall off the framing, you might want to take a look at those.

there are also foam products (almost like tape) that can be placed between the drywall and the framing.

There is also a product called "green glue", it's used between two sheets of drywall as a sound deadener. Fairly pricey though, if I recall the tubes are about $12 and you use 2 tubes between two sheets. So you're looking at about another $25 per sheet of drywall.

There are other membrane-type materials that you could use as well, they are stapled over the framing and covered with drywall. With the membrane you could likely go with just one layer of drywall."

Which one(s) of these would you recommend for our situation to give us the best soundproofing around that pocket frame? And what kind of membrane material are you talking about (please name names, it's o.k., considering how much Kerdi and Ditra get mentioned here)

As ever, many thanks :)

Comments (14)

  • MongoCT
    18 years ago

    If I'm your best hope, well, then just give up all hope here and now...(g)

    I'll do a quick and dirty now and try to post links later, but in the meantime try googling on these:

    The aluminum channels are not all the same. Resilient channels are specific to sound deadening. RC-1 is used on walls. On walls, mount with the narrow flange on the bottom and the wider flange up. This causes the weight of the drywall to pull itself away from the framing. Isoaltion is the key. The flanges should all be pointing in the same direction.

    Screw the drywall to the RC channel in between the studs, not over a stud. You don;t want to bond the two together. Use RC-2 on ceilings Same thing sort of, just a double-wide flange.

    RC adds about a half-inch to the thickness of the wall or ceiling.

    Homasote: It's a cellulose-type board, comes in varying thicknesses, 1/2" is the norm. Good for sound deadening. Comes in 4' by 8' sheets, it's about $15 a sheet, might be more.

    Mass loaded vinyl: This is GOOD stuff. This is the membrane material I mentioned in a previous post. Very dense (high mass), comes in rolls, usually 48" wide by as long as you need. HEAVY (from the high mass, obviously), about 1# per sqft. This might be your better bet. Different thicknesses as well.

    If you only have additional thickness for one product, I'd recommend the MLV. When I order MLV I order "MLV". I'll dig through invoices to see what the actual brand name is.

    MDF doors will deaden sound better than wood or hollow core.

    Got to run, but this should get you started. Look at MLV first. It'll give you the most STC for the thickness.

    In addition to the regular RC channels, there are neoprene clips that can be used as an additional isolation layer. Cha-ching!

    Don;t forget to use an acoustical caulk beween the framing and the floor, etc. Or a thickness of membrane. It'll minimize vibrations being transmitted from wall-floor or floor-wall.

    You might consider a floor sweep on the bottom of the door to seal the gap between the door and the floor. Not the most visually attractive, but it does get the job done.

    Gotta go!

    Mongo

  • mahatmacat1
    Original Author
    18 years ago

    Excellent, mongo--I just looked up the MLV and I think this is what will be best for us. I found some online--does this resemble what you're thinking of?

    And we didn't know about using the acoustical caulk or membrane between the framing and floor--that's brilliant. We'll definitely use it.

    Just wonderful. Thanks so much.

    Here is a link that might be useful: is this it?

  • MongoCT
    18 years ago

    Yes ma'am, you found it.

    Here's another site for price comparisons. Seems like they have a lot of info there as well.

    I'll be running up to Beantowm tomorrow, so if you have more Q's post them but I won't see them until Tuesday night.

    Mongo

  • mahatmacat1
    Original Author
    18 years ago

    Thanks, mongo. We'll be ordering some and sharing the info with our friend who's doing the framing. Looks like there are *many* options for soundproofing other than that really expensive drywall, after all. I just love this.

    And my bigger question: how in the heck do you know so much about so many areas?? I meant what I said in the first line of the thread...I hope the people you work with appreciate what amazing luck they have.

  • brickeyee
    18 years ago

    The noise problems with pocket doors are caused by no door protruding into the pocket when the door is closed, and the lack of a stop bead on the non-pocket side of the jamb.
    All the insulation you put in the pocket will have zero effect on the sound transmission when the door is out of the pocket and closed.
    When I install pocket doors I routinely extend the pocket edge about 2 inches to catch a guide rail in the bottom of the pocket that keeps the door from swinging (door bottom is grooved to engage the rail), and add stop beads on the non-pocket jamb.
    The rest of the noise issue is taken care of by using a thicker wall and 2x studs turned flat on 12 inch centers.
    The small loss of room space is more than maken up by the far more rigid wall created.

  • miruca
    18 years ago

    check out QUIETROCK at www.quietsolution.com
    It installs like sheetrock but is equivalent to multiple sheets of sheetrock. Amazing product - it's going in my floor/ceiling assembly between floors and it will encapsulate an efficiency apt.

  • mahatmacat1
    Original Author
    18 years ago

    brickeyee, we're doing a 6" wall on that wall--I'll mention the studs turned flat...I'm not quite clear what you mean about the guide rail in the bottom of the pocket--do you mean attached to the floor inside the pocket area of the wall? Where can I get this--we're using Johnson pocket door hardware...thanks very much for your help.

  • brickeyee
    18 years ago

    I use 3/4 inch aluminum angle.
    Groove the door 1/8 inch wide and 1/4-1/2 inch deep on the bottom. Stop short of the 'show' edge of teh door so the groove does not show.
    The aluminum is fastened to the floor in the pocket.
    The plastic guides Johnson supplies are the only complaint I have about their stuff. The tracks and rollers are good except the old style one they started carrying. Probably to compete with the Stanley junk.
    The 3 wheel bogies are smooth, strong, and reliable. There is n o way for them to come 'off the track' like the older systems.

  • mahatmacat1
    Original Author
    18 years ago

    OH, I get it--are you talking about the sound of a pocket door /frame itself? Like in terms of rattling inside the pocket, etc? I meant insulation inside that wall when the door is pulled closed, since the wall is so much flimsier than a stud-built wall.

    We're using the three-wheel kind of hardware; glad to hear it works well. I'll show our framer the 3/4" angle idea. I'm so constantly impressed by the quality of workmanship shown by professional folks who frequent this forum. But then again, only people who really care about their work would bother to find a place like this in the first place! Thanks again. :)

  • miruca
    18 years ago

    fly when you get that door in let me know how the sound issue was resolved. Thanks....

  • brickeyee
    18 years ago

    If you beef up the studs in the wall by using 2x6 flat on 12 inch centers the sound properties are actually pretty good.
    You will leak a lot more sound around the door when it is closed than through the two layers of wall and double studs making up the pocket.
    A typical pocket door installation has no stops on the non-pocket side, just the door butting against the jamb.
    Adding a single (or even a double set) of stops eliminates the direct path for sound.
    The other sound path is past the door on the pocket side. The door should be wider than the opening by at least 2-3 inches. This can be accomplished by using either a wider door than the opening or extending the door by attaching some 2x lumber planned to match the door thickness to the pocket edge of the door. These are all the routine things for a pocket door in a residential bathroom.
    Adding additional layers of drywall to the walls on each side of the pocket also reduces sound transmission significantly.
    With all the fancy products on the market, when I build rooms that must stop sound transmission I switch to steel studs and multiple layers of 5/8 drywall, and then fill the cavities with un-faced fiberglass insulation. Acoustic caulk is used to seal the top and bottom plates to the ceiling/floor decks.
    These rooms are built and many are actually tested to verify the sound rating of the completed walls. They are used to protect classified discussions from being heard outside the room.
    Drop seal doors with sound rated seals (not the thin little smoke seals), steel doors with sound foam filling, and white noise generators for any ducts penetrating the sound walls complete the typical package.

  • mahatmacat1
    Original Author
    18 years ago

    Thanks again -- now I have a follow up question about the door hardware itself. Should we go with Johnson or Cox 32 series? The Johnson is the normal three-wheel hanger with the completely covering (jump-proof) aluminum track, sold as a set at HD.

    The Cox is hardware sold separately from some "ABS" pocket door frames. It's the 32 series, with 4 wheels and the jump-proof tracks as well.

    What do you use?

    Thanks!

  • brickeyee
    18 years ago

    I use Johnson 111PD hardware for most doors, but switch to the 100PD for larger or heavier doors.

  • mahatmacat1
    Original Author
    18 years ago

    Thanks, brickeyee. Maybe we'll use the 111 for the single-light glass/fir doors, and the 100PD for the solid-core...or should we just use the 100 for all of them?