Thanks Rod. (Got a lot of mileage out of your book, BTW...)
I've considered an independent ceiling, but because the existing timber framing is at 8", I prefer not to cut into my headroom another 6 inches, though if the performance were to be significantly better, I suppose I'd have to consider it.
I'm not familiar with the clips, but I'll see if I can find a UK supplier to see about cost.
Thanks again.
Why would you have to loose 6" - you can step the new joists up betwwen the old ceiling joist with no problem.
I can usually get a new ceiling down to only 1 1/2" to 2" of loss.
Rod
What a great idea. I never would have thought of that. So the old & new joist would be like interlocking your fingers.
I guess you would need to have nothing in between those existing joists: duct, gas lines, wiring, etc.
Very cool...
This is something I gave alot of thought to. I really liked the benefit of NO weight being added to the deck with an independantly framed ceiling. I also liked the idea of the lack of contact - the reason it's the most effiecient ceiling frame...
To your question of utility line - Yes, you'd have to have a clear path or run an aditional beam across to bridge under utility.
To give an Idea of what I did (right or wrong, it's what I did and I think it worked.. ) -
Cross bracing for the existing deck:
Those triangle braces are also in the middle of the ceiling joist against the drywall. If you're spanning greater than 10', I'd likely do something a bit more sturdy.
If dealing with wood framing - if you're REALLY close as I was in the difference between the floor joist and ceiling joist (1'' or less), then pick your lumber carefully (no hockey sticks) and put drywall up right after you frame it up. This way the boards won't kick/warp on you. I had to sister one joist up with a 2x4 as the 2x6 length had lifted.
An update: builder and I have chatted and are both looking into insulation options. It was actually quite difficult to find the density information for many of the products as it isn't listed on the UK manufacturers websites, even under the technical specs. A few calls to the manufacturers themselves were met with an immediate reluctance to deal with a non-tradesman. Only after being rerouted through suppliers (who sent me back to the manufacturers) was I able to get to speak to anyone with useful information. Then, they would ask what I was doing and when I told them I was soundproofing, I would then have to go through explaining to them why I wanted lower density materials, because as far as they are concerned, their expensive, high-density acoustic insulations are the only way to go. Even after mentioning the Canadian government report, many thought that I was barking mad to use flimsy fibreglass for acoustic purposes. When I tried to circumvent that conversation with one bloke by telling him my purposes were "thermal" he retorted, "well why would you need to know the density, then?" Around the mulberry bush again.... :D
Anyway, we all knew this before, but it's clear that even the materials suppliers don't have a full understanding (or have a willful blindness and greed) of the principles of sound isolation, in spite of the data (quite convincing to me) available out there. Heck, the builders are in on it, too. I had a guy come out to do a quote and I was very specific with him about using certain materials, like bog standard plasterboard as opposed to "acoustic" boards, etc. He had crazy ideas about how my concrete slab (isolated) was going to create so much flanking noise that I would need to put down rather expensive rubber matting, etc. and seemed genuinely shocked when I said that I didn't think a little rubber matting was going to make a difference at frequency levels low enough to rattle a concrete slab surrounded by tonnes and tonnes of dirt... By the time his (utterly extortionate) quote came back after nearly a month, he had filled it with so many unwanted and unnecessary products/techniques that his price was fully 3x higher than what I'm going to end up spending. And I'm not doing a DIY build but using a reputable qualified builder. I was quite lucky to find a conscientious guy who didn't have a lot of preconceived notions about sound isolation so when I started showing him diagrams and information gleaned from here, Rod's book, etc. he was open and receptive. I said "do this" and he asked "why" and once I explained the reasoning and showed him the research, he said, "okay". A huge contrast to some of the other know-it-all guys I've dealt with through the quote process.
Anyway, I just want to say thanks to all the forum members here, especially the heavyweights like Rod, and Knightfly. But not to forget all the people who have shared hundreds of pages of their designs and experiences. I've gotten more useful information from here than I did from months of hunting the web, talking to builders, suppliers, and manufacturers. This forum is an incredible resource. Cheers!
:D
Construction has begun with the concrete block wall being built where the roll up garage door used to be.
However, a question about drywall has come up. 15mm plasterboard (5/8" for the folks in the colonies..) is not "standard" in the UK and can be quite a bit more expensive. To keep my original quote intact we're considering using a mixture of 12.5mm and 15mm boards. The builder's initial quote mistakenly used 12.5mm/0.5 inch boards because the measurements were lost in translation... And while that's not a conversion mistake on the scale of the Hubble, it is significant on my budget. My initial reaction (besides the fear of reduced LF isolation :shock:) is to concentrate the heavier plasterboard closest to the sound source - i.e. on the inner wall rather than to mix the two thicknesses on each wall.
Can any of the gurus (or anyone else with relevant experience) chime in? Would that be the safest bet?
I'm in luck in the case that it doesn't turn out because I will still have access to the outside of the two plasterboard "outer" walls to add another layer of 12.5mm board if I need to add mass after the fact, when I've got a few more pounds in the bank again.
Any help would be much appreciated.
Great news, for me at least! :):):)
Construction is almost done on my drum studio. The two outer plasterboard walls need to be taped, muddied and caulked, insulation installed over the ceiling and the second of two doors hung. There may be some nooks and crannies in the outer garage shell that need to be plugged up as I caught sight of some daylight creeping in at one of the corners earlier today while crawling around in the ceiling joists. :evil: I'm definitely getting a lot of isolation loss through the doorway, which will be doubled-up tomorrow, hopefully cutting off a primary sound escape route.
But, here's the good news. In spite of being unfinished, I appear to be getting some good results. My wife kindly stood outside with a sound meter while I whacked a snare drum tonight. The drum was clocked at 116dB inside. She got readings at about 2 feet from the outside wall of 66dB. Closer to my nearest neighbour's house, she registered 56dB. We are about a 1/4 mile from a motorway and have a constant background noise of between 50-54 dB until very late in the evening. In other words, a little more work, and I should be able to blend into the background! She described the sound outside the studio as a quiet radio or footsteps. Now, I understand that's only an (mostly useless, I know) STC of around 50, and I figured I'd be doing better given my construction. However, I may have underestimated the porousness of the clay tiled pitched roof, and my ceiling is currently just 2 layers of 15mm plasterboard on an independent frame resting on my inner walls.
The real test will be my bass drum, but I'm happy with my results so far. I'm not really concerned with STC points, or decibel levels, as much as being able to blend into the noise of the neighbourhood and not be noticed.
Looking forward to being able to practice and teach again!
:D
Boomka77,
As I'm also in the UK I am intersted in what type of insulating material you decided to use eventually to replace the RWA45.
The builder I've been talking to also recommended RWA45 so I need to give him an alternative.
I'm also struggling to find the density of many commercial insulating materials.
I'd appreciate any help you can give here.
Dave