OSB Fastening to Ceiling and Walls

LarryM · 07-11-2012, 11:42 AM

I am attaching 19/32 OSB and a 2nd layer of 23/32 OSB to my ceiling. What length drywall screws should I use to attach the product?

I was thinking 1 5/8" for the first layer of 19/32 followed by 2" for the 2nd layer of 3/4" (attached to both the 1st layer and the ceiling joists)

I will also be putting 3/4" OSB on the walls, I was thinking 1 5/8"

I have a Senco screw gun so I would like to use their screws for this project (or equivelent Hilti or other collated screws)

Thanks

joecaption · 07-11-2012, 12:04 PM

Why OSB and not sheetrock?
Most codes will require 5/8 fire rock be used on a ceiling.

LarryM · 07-11-2012, 12:34 PM

Quote:

Originally Posted by joecaption

Why OSB and not sheetrock?
Most codes will require 5/8 fire rock be used on a ceiling.

Sheetrock will go over the OSB.
This is for a home theater so I am using the OSB for sound suppression.

CopperClad · 07-11-2012, 12:50 PM

Wow. You're adding a ton of weight to ceiling joist. What size are they and how far do they span?? If all your trying to do is some soundproofing there are many other cheaper and better options then OSB.

AGWhitehouse · 07-11-2012, 01:01 PM

thickening the osb won't help you with sound near as much as resilient channels. The one layer of osb is good for massing, but i'd negate the second layer and do resilient channels instead. That will mitigate the transfer of vibrations from the gwb surface into the floor framing.

LarryM · 07-11-2012, 01:09 PM

Quote:

Originally Posted by CopperClad

Wow. You're adding a ton of weight to ceiling joist. What size are they and how far do they span?? If all your trying to do is some soundproofing there are many other cheaper and better options then OSB.

I already have the material. The span is about 12' until it rests on the support beam. The joists are Georgia Pacific Wood I Beams GPI40 if I recall correctly.
http://www.gp.com/build/product.aspx?pid=1390

I would be adding 7.6 PSF to the ceiling (23/32 OSB = 2.6, 19/32 OSB = 2.0, 5/8 rock = 2.8)

LarryM · 07-11-2012, 01:13 PM

Quote:

Originally Posted by AGWhitehouse

thickening the osb won't help you with sound near as much as resilient channels. The one layer of osb is good for massing, but i'd negate the second layer and do resilient channels instead. That will mitigate the transfer of vibrations from the gwb surface into the floor framing.

I decided against the resilient channel due to the cost.

I actually don't have the 19/32 OSB yet. I have just a few sheets so I could opt to not use it. Would you not use the 19/32 if you were not using resilient channel?

LarryM · 07-11-2012, 01:16 PM

Quote:

Originally Posted by CopperClad

Wow. You're adding a ton of weight to ceiling joist. What size are they and how far do they span?? If all your trying to do is some soundproofing there are many other cheaper and better options then OSB.

What else would you recommend for soundproofing?

In addition I am using Green Glue in between layers and acoustical sealant in the seams.

AGWhitehouse · 07-11-2012, 01:24 PM

Quote:

Originally Posted by LarryM

I decided against the resilient channel due to the cost.

I actually don't have the 19/32 OSB yet. I have just a few sheets so I could opt to not use it. Would you not use the 19/32 if you were not using resilient channel?

You can use it and, technically, it will help some, but I don't know how much of a difference it will really make. Sound is a vibration wave and you need to dissipate that wave to "block" sound. Massing helps as it absorbs some of the energy by making the sound waves move the mass in order to transfer through. But, when you're talking a floor deck, the whole floor itself can kind of act like a speaker of sorts. So one layer of 19/32 OSB won't do a whole lot in dampening that speaker. The resilient channels, however help to de-couple the layers of the floor assembly and don't give the vibration waves a mechanism to travel through. The gwb ceiling vibrates from the direct intake of the sound energy and the resilient channels break up that energy before it reaches the floor structure. If you allow the sound waves to hit the structure, you'll have a tough time really dampening the sound. That all said, budgets are budgets, I certainly know how that goes.

LarryM · 07-11-2012, 01:35 PM

Quote:

Originally Posted by AGWhitehouse

You can use it and, technically, it will help some, but I don't know how much of a difference it will really make. Sound is a vibration wave and you need to dissipate that wave to "block" sound. Massing helps as it absorbs some of the energy by making the sound waves move the mass in order to transfer through. But, when you're talking a floor deck, the whole floor itself can kind of act like a speaker of sorts. So one layer of 19/32 OSB won't do a whole lot in dampening that speaker. The resilient channels, however help to de-couple the layers of the floor assembly and don't give the vibration waves a mechanism to travel through. The gwb ceiling vibrates from the direct intake of the sound energy and the resilient channels break up that energy before it reaches the floor structure. If you allow the sound waves to hit the structure, you'll have a tough time really dampening the sound. That all said, budgets are budgets, I certainly know how that goes.

Thanks for the info, I completely agree. I plan on doing the 2nd layer of OSB in order to add more dampening with another layer of green glue. The added mass is nice but wasn’t the driving decision hence my reasoning for doing 19/32. Thinking now I should have just done 2 layers of 19/32 but I already ordered the 23/32 several months ago when I originally planned on doing resilient channel. Then I was hit with the sticker shock of resilient channel and modified my plans to the 2nd layer of 19/32.

LarryM · 07-11-2012, 01:37 PM

So for the original question...what screws should I use

CopperClad · 07-11-2012, 01:38 PM

Butt joints read that post from a few weeks ago. There is a link towards the bottom of the post with good information. Any questions regarding soundproofing I would ask the original poster of that thread, seams he is very knowledgeable in the topic. I love surround sound, and encourage your soundproofing, just want to make sure you aren't wasting your time and money with the OSB and giving yourself a final product that you are satisfied with and enjoy. Good luck on your project !

LarryM · 07-11-2012, 01:52 PM

Quote:

Originally Posted by CopperClad

Butt joints read that post from a few weeks ago. There is a link towards the bottom of the post with good information. Any questions regarding soundproofing I would ask the original poster of that thread, seams he is very knowledgeable in the topic. I love surround sound, and encourage your soundproofing, just want to make sure you aren't wasting your time and money with the OSB and giving yourself a final product that you are satisfied with and enjoy. Good luck on your project !

The OP from that thread comes from the same group of nuts I get my information from. Building a Home Theater and allowing your wife to sleep is such a difficult task.