Flimsy exterior wall.. how to construct interior walls?

Hi all- I'm planning to convert a small (15.5'l x 9.5'w x 8'h) un-finished, one room backyard workshop / shed to a music studio. Overall objective is a space suitable for a small band to rehearse with electric instruments, at moderate volume. Given the limitations of the existing building (photos here) and my limited finances, I'm not looking to re-create Abbey Road here. Hence the budget is tight, and though I'll be satisfied with "good enough" isolation, of course I'd still like to maximize the isolation to the extent possible. The exterior walls are currently near-nothing: simply a layer of tar paper, i.e. building paper beneath the outside cedar shake shingles, affixed to a 2x4 frame. Interior walls are un-finished. I currently plan to finish out the walls and ceiling with two layers of 5/8" sheetrock, attached directly to the 2x4 studs and with 3" un-faced batt insulation loosely placed in the cavities. Question: is there a way to improve upon this design significantly without incurring more than ~$200 in incremental costs? I've read Rod's book (great book!) and others by Alton Everest, etc... and of course have learned a ton from this forum after lurking here a while. I've considered several alternatives and so far cannot justify their added expense vs. putting these funds towards better door and windows: RC, iso-clips mounted on hat channel, and Green Glue. Creating a second interior wall is similarly problematic, and also eats up floorspace that is very scarce in this case. Rod's book actually describes a situation similar to this (p.56 "Existing walls are going to be your biggest challenge. The exterior walls are probably a long way from being airtight...") as a common problem for which there is a solution... but I'm not seeing an obvious way to improve on the simple "two layer of sheetrock" approach without spending several hundred dollars in material + labor. But... please feel free to point out where I've overlooked something! :) Thanks, Greg

Aloha and welcome to the forum, Greg Congrats on your studio build! Any chance you could please:

Edit your profile to include your location. This is very important, because this is a worldwide resource, and as such, material costs and availability vary widely. For example, masonry is cheaper than gypsum in some parts of the globe, whereas it's the exact opposite in other regions.

You'll probably get more of a response by doing so and this will really come in handy two or three posts down the road. It's also part of the forum guidelines: http://www.johnlsayers.com/phpBB2/viewtopic.php?t=7572 http://www.johnlsayers.com/phpBB2/viewtopic.php?t=3231 Thanks! Here's a diagram to give you an idea of what kind of STC you might be able to accomplish. Looking forward to your build! Aloha 8)

Thanks Kendale- Just added my location to my Profile. Thanks for pointing out it was missing! About the STC ratings... I've seen several of these, and most of them, incl the image attached, assume that sheetrock will be mounted on both sides of the wall frame, which is certainly preferable to installing sheetrock in multiple layers on only one side of a frame, as I'm planning to do. Unfortunately, mounting sheetrock on both sides of the frame is not an option in my particular case. The frames + exterior walls are already in-place, and I have neither the budget nor physical space to add a second wall inside the first (which would allow me to properly mount a layer of sheetrock on the exterior side of the wall frame). I recognize that this is inherently sub-optimal, but it's what I have to work with on this budget, unfortunately.

Lots of necessary details missing. How loud are you? How close are your neighbors? Is the shed slab on grade? Ventilation? I'm afraid your tight budget is probably going to get in the way of your making substantial improvements.

It'd certainly cost more than $200, but you know what you should do -- rip down the shingles/clapboard and start over with exterior sheathing. At the very least, switching to T-111 siding would give you more mass than the clapboard. - Andy

sharward wrote:

Lots of necessary details missing. How loud are you? How close are your neighbors? Is the shed slab on grade? Ventilation? I'm afraid your tight budget is probably going to get in the way of your making substantial improvements.

I hear ya... I'm OK with the idea that this is never going to be a bullet-proof structure that will host the next OzzFest without the neighbors noticing (until their pet bats start disappearing :wink:). As such, I'm not looking to invest a ton of money into it, which limits the options. I guess I'm mainly checking in here to see if I may have overlooked any relatively minor, but important idea before I finish out the flimsy walls. For example, if a heavier insulation like rockwool / mineral fiber would yield substantial benefits over regular ol' batt insulation in this particular case, given the low-mass of the walls. Re: the questions above: the closest neighbors are about 20 yards away, they're friends of ours. In other directions, the neighbors are a good distance away, and here in Texas (as in Sacramento, probably) folks spend a lot of time indoors with the AC running for many months of the year. Volume will be "low" most of the time, but I'd ideally like to allow for the scenario in which a 4-person band with electric instruments (moderate volume) wouldn't be hard throughout the neighborhood. The shed is on pier + beam, the existing floor is merely a layer of 3/4" plywood sitting atop the 4x8 floor joists. As you might imagine, I'm looking to fortify this on a minimal budget (given the fundamental limitations of the structure + my finances available for this project!), hence am planning to add a layer of MDF (or plywood) on top of this, then a final layer of flooring (probably bamboo or Pergo), with some sort 'cushioning' of between layers. Will also add support below in the form of additional 4x4 piers on top of precast concrete pilings, and cross-bracing between some of the piers, with the idea that I'd prefer that the structure not collapse with the weight of the extra drywall and such. :) Finally, I'm planning on a Soleus cooling-only mini-split and a separate electric baseboard heater. The electrician who will do the wiring recommended this approach instead of an all-in-one heat pump, for simplicity, cost, and overall effectiveness reasons. So... as you can probably tell, the overall design objective here is "just make it adequate." :) But of course, there are varying degrees of "adequate", just hoping to hit the higher end of it while still remaining within the "adequate" budget! :)

Bass Rocks wrote:

It'd certainly cost more than $200, but you know what you should do -- rip down the shingles/clapboard and start over with exterior sheathing. At the very least, switching to T-111 siding would give you more mass than the clapboard. - Andy

Thansk Andy- I hear ya on the above, I actually did consider the possibility of re-doing the exterior, but abandoned the idea for budgetary reasons. Also thinking that, in the event that (i) the final product just isn't working for sound isolation purposes, and (ii) we decide to stay in this house for longer than the next few years... then it would still be feasible to replace (and fortify in the process) the exterior side of the wall even after the interior is all finished-out, without much, if any, "re-do" work.

Honestly, I would recommend you do what you want to do for your own sake (comfort, appearance, acoustics) and assume you will have no appreciable reduction in soundproofing. What you've described (especiallly the single leaf floor system) spells soundproofing failure to me. Fortifying the sides of a bucket without patching the holes in the bottom won't stop the bucket from leaking. Be aware of the noise ordinances in your town. In all likelihood, your noise levels will be illegal, even if nobody complains right away. If you keep your spending minimal, you won't feel too bad when you eventually get shut down. Sorry, that's just reality. I wish I could be more optimistic or encouraging. --Keith :mrgreen:

I second Keith's comments - my first studio was built into a pole barn, nearly identical construction except the outer covering was T1-11 - my wife could hear from the house 100 feet away exactly what song I was playing on an acoustic piano. If nothing can be done about your budget, I'd resolve the idea that you won't get much isolation - besides the flimsy outer walls, there is only one leaf of mass in the floor, and probably not much more in the ceiling. Glad your neighbors are also your friends 8) Steve