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Weight concern in adding an extra layer of drywall ceiling

Weight concern in adding an extra layer of drywall ceiling

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  #1  
Old 12-31-17, 04:16 PM
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Weight concern in adding an extra layer of drywall ceiling

Hi all

I'm routing some wiring for my home theater room that is 15' by 13'. The room is on the first floor with another bedroom above. The joists above the home theater room are 2x10s running along the 15' length of the room at 16" OC. I'm going to have to open up several large strips of the ceiling to run wires and cables, and stick some roxul in there fore better sound dampening.

Now the tricky part is that it is a popcorn ceiling. So instead of patching it back up to with more popcorn texture, I would like to add another layer of drywall along with Green Glue. My concern is the added weight. If I use the 5/8" type X drywall, which gives better soundproofing performance, I'm essentially adding 500lb of weight onto the ceiling joist. Should I be concerned about this?

Thank you so much.
 
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  #2  
Old 12-31-17, 04:25 PM
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Not at all. Would you worry if two 250 lb people were in the room upstairs above this? Nope! But it's essentially the same thing, except the drywall will become part of the dead load, while people and furnishings are live load. Plus your drywall weight will be distributed evenly across the entire floor system, whereas two 250 lb people could be standing in one place as a point load. Even then, its no problem, the floor can handle it.

Your span is at the upper limit for 16" oc joists, but that includes 10lb Sq ft for dead load (building materials) and 40lb Sq ft for live load (people and furniture). Your 5/8 drywall will add 2.3 lbs per Sq ft... so you are still likely under or close to 10 lbs per Sq ft.

Now a 3000 lb. hot tub would probably be a cause for concern.

I'd suggest you scrape the popcorn off first.
 
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Old 12-31-17, 04:30 PM
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If you are only opening strips of rock to add wiring and insulation.... what about the rest of the ceiling ?
 
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Old 12-31-17, 04:37 PM
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Hi XSleeper. Really appreciate your insight. But stop tempting me with the hot tub idea!

Anyway, what's the reason for you to suggest scraping off the popcorn first? I actually thought about it. And I've tested a small patch, which responded well to a spray bottle and a putty knife. However, I read that a lot of these popcorn textures contain asbestos. So sealing it in with a layer of drywall is really shooting two birds with one stone. Actually three birds:
1) getting rid of the ugly texture
2) sealing in possibly asbestos
3) soundproofing

And I'm also going to use Green Glue, which should give me a lot of play to even out the new drywall sheets despite the uneven texture behind them. So I'm really curious why it would be best to scrape off the popcorn first. Thanks again.
 
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Old 12-31-17, 04:39 PM
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I'm with Pjmax on this one.
Way more to it to do it right then just patch insulation.
How to Soundproof a Ceiling - Soundproofing Products for Ceilings
 
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Old 12-31-17, 04:41 PM
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Hey Pete
The plan is to
1) cut out the opening
2) lay the cabling
3) put the cut out drywalls back with minimal patching and sanding
4) add another layer of drywall to the entire ceiling
 
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Old 12-31-17, 04:44 PM
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You want drywall to drywall contact with the glue, not drywall to texture. And you will have a height difference at your patches if you dont. And yes, texture comes off quite easily when sprayed and scraped. It's like a 15 minute job. Even if it was asbestos, it's not friable if wet, which is what you would do. The texture would have to be from the 70s to have any chance of containing asbestos. Even if it is, you can do safely. It's your house. Cover it up and now you have concealed it, a problem if it really is asbestos and you go to sell, you must report it.

If the house was built in the 80s, it's a safe bet it's not.
 
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Old 12-31-17, 04:45 PM
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Hi Joe

I see what you are saying. I should explain that I'm not just sticking roxul in a few patches. I'm going to open up 3 separate strips of ceiling that are perpendicular to the joists. The strips will be around 2' wide. This way I can fill the entire cavity with roxul safe'n'sound.
 
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Old 12-31-17, 04:52 PM
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Well XSleeper, I can't be sure when the popcorn ceiling was applied, but yes the house was built in the 70s.

I'm using the Green Glue for soundproofing purpose, not for adhesion. The new ceiling drywall will still be secured by screws. I was actually hoping that the popcorn texture will provide further decoupling between the two drywall layers.
 
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Old 12-31-17, 04:59 PM
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If you want decoupling, use resilient channel. That's how hotel ceilings are built.
 
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Old 12-31-17, 05:11 PM
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Ya I've though about resilient channels too. But thanks for the suggestion though.

The thing is that I understand fully I'm NOT going to be able to address noise issue with simply treating the ceiling. I definitely will get noise travelling up the walls too. But really I'm not looking to do the ultimate soundproofing. I'll either be in the upstairs bedroom sleeping, or be in the home theater watching stuff. Adding another layer of ceiling drywall makes sense for me because it kills 3 birds with one stone:
1) getting rid of the ugly texture
2) sealing in possibly asbestos
3) soundproofing

So essentially, achieving SPC Ceiling Solution #1 in Joecaption's link is good enough for me. Doing anything more will enter a zone of diminishing return for me. But still I really really appreciate your advice.
 
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