Ground-up studio build in Perth

Hi guys, I've finally finished beefing up the roof... Wow, what a terrible job. So I've got 20 bags of the insulation sitting here that I can't use in the cavity, do you think it'd be worthwhile putting it in between the rafters like in the picture? Do you reckon it'd help at all with insulating heat/cold or even make a difference to the isolation?

Birdsteeth wrote:

Hi guys, I've finally finished beefing up the roof... Wow, what a terrible job.

yeah, cutting small bits of plaster isn't much of a laugh, and there's a few issues going on in that pic that need to be addressed. I can see plywood underneath the plasterboard there which means the extra layer of plasterboard isn't doing what it's meant to. With beefing-up you have to cover the entire surface. no gaps. You have to seal all the air gaps where the extra layer of plaster meets the rafters. If you dont do this you effectvely have 'holes' in your isolation as the sound will be leaking out of all the gaps and unsealed sections. There also seems to be an issue with the MDF that you've used to span the gap between the top plate and the ceiling. I'm guessing that it's only one layer thick, which means all the work you've done with your brick walls for isolation will be void, as bass frequencies will hit that MDF and go through it like a freight train :( Once you beef that up it also needs to be sealed air tight. Any of those gaps around the rafters and between the MDF/ceiling join also need to be sealed air tight. This is why you'll go through many, many, many cases of acoustic sealant :shock: I know that all sounds quite pedantic, but that's pretty much studio building in a nut shell

Birdsteeth wrote:

So I've got 20 bags of the insulation sitting here that I can't use in the cavity, do you think it'd be worthwhile putting it in between the rafters like in the picture?

You might not have quite got the gist of the cavity here. I haven't read back through the whole thread, but i'm pretty sure you're doing a ' room within a room' construction? If so, then you'll be constructing a bunch of walls inside your brick shell that won't touch your brick shell in any way. No screws, nails, glue, skyhooks....nothing. This also applies to the ceiling. you'l be building a ceiling that rests on those internal walls that does not touch your existing ceiling in any way. No screws, nails, glue, skyhooks, nothing :wink: That means you also have a cavity between the existing ceiling and the new, independant ceiling you'll build. That cavity gets treated like the wall cavities with the same density of insulation. So with all that in mind, i think you have a bunch of insulation bound for ebay. Hope that all makes sense and sorry if it's a bit of a downer on the build, but these are the details that you really need to get right. You've gone to a lot of trouble (and expense) with the shell so far, and it's looking great....but this is a crucial part of the build that can't be rushed. (not that any of it can be rushed. Took me 3 years to get over the line :shock: ) all the best, steve

G'day Steve, Thanks for the reply. That photo is a fair few days old, I've been doing exactly what you suggested in beefing up the MDF with gyprock and GreenGlue as well as sealing the gaps with the GreenGlue sealant. I have a problem though with cutting bits of gyprock that are say 2cm by 900mm to go in the larger gaps and sealing them with the sealant will send me broke :x . Do you think I could use some joint compound http://www.bunnings.com.au/gyprock-csr- ... d_p0730736 to fill those bigger gaps? Would the density be similar? Oh, and the insulation is going on Gumtree... I've let it go haha. Thanks, Sam.

Birdsteeth wrote:

I've been doing exactly what you suggested in beefing up the MDF with gyprock and GreenGlue as well as sealing the gaps with the GreenGlue sealant.

if you can it'd be better to use 16mm fyrchek plaster for this part, as it has better density and rigidity for the job. It's also the one you want to use for the build of your internal walls.

Birdsteeth wrote:

Do you think I could use some joint compound

I don't think that'll work too well in that application. The gap will be too wide and it'll tend to slump and then crack once it's dry. It's really made for thin coverage like the joins between plasterboard and for finishing the beveled joins. I hate to say it, but you're probably stuck with cutting small bits of plaster, or MDF, or ply that have a sililar density. steve

I'm back! The studio build was put on hold for a bit with the safe arrival of my first child, Clyde! Over the past couple of weeks I've finally managed to finish off beefing up and sealing the outer leaf. One of my mates who I play in bands with is a carpenter and he was responsible for kicking me in the butt and helping me get on with it. The plan now is to build the live room first and get it completely finished so at least I'll have somewhere to practice and if any thing's not working I'll still have a bit of access to the outer leaf. Next step is to buy all my Soundscreen insulation and get busy framing up the walls and ceiling. Sam.

looking good there Sam. everything looks sealed up like a goddamn submarine :lol: A couple of quick questions, just out of intrest.....why so many small bits of plaster? were they all offcuts from the house build? (I ask becasue you would have gone through a hell of a lot of sealant sealing up so many small pieces) Why is the roof 'stick built' on RSJ's and not trusses? (just curious) all the best, Steve

G'day Steve, The roof has 15mm marine ply on top of the rafters and that's what I've fixed the 16mm gyprock onto, on the underside with a layer of Green Glue. The sheets of gyprock I bought are 3m x 1.2m, I had to cut the sheets anywhere between 830mm and 870mm to fit in between the rafters. As I did most of that work myself, that was about as much weight as I could handle without falling off the scaffold! The smaller sheets on the wall are beefing up and sealing over the 'plugs' I made with MDF to seal up the gaps where the rafters go over the top of the wall and into the eaves. So yeah, I used heaps of sealant but I'm super paranoid about any gaps, and the way things are going what's another few hundred bucks on sealant between friends? I thought they'd use trusses for the roof as well, the way they did it with the struts on the LVLs just seems to be the way they do things over here in the West. The roof on the house built at the same time is exactly the same as the studio. When we designed the house plus the room, I just asked for the biggest room they could possibly fit on the block and that's what they came back with. It's funny, a mate of mine just built a house in Victoria and it was a stud-frame build, you never see that in W.A., it's all double-brick over here. Sam.

Oh, here's a question I had too... I've been reading up on the Bradford Soundscreen insulation and found something interesting in the specs for the different batts - the 70mm 2.0 batts have a higher density than the 110mm ones. Would I be better off with the higher density or does the 40mm thickness difference negate any higher density? The cost is about the same between the two, so that's not a factor; just wondering which would be more effective? Or am I being too pedantic (if there's such a thing in studio building haha). Plus I think, unless I'm mistaken, the R numbers refer to thermal ratings which have nothing to do with what we use it for?

... and another thing I've been thinking. Has anyone ever done a combination of inside-out walls with normal walls? I was thinking of making the walls in 1500mm sections on the ground as they'd be easier to stand up with 3 or so people lifting and the thought came to me. Is there any reason not to do it sound-wise? I see plenty of studios with hard gyprock surfaces on the inside and then diffusers hung on the walls, this would be the same outcome built into the room? Hopefully the pictures explain it as well. Thanks, Sam.

Birdsteeth wrote:

I've been reading up on the Bradford Soundscreen insulation and found something interesting in the specs for the different batts - the 70mm 2.0 batts have a higher density than the 110mm ones. Would I be better off with the higher density or does the 40mm thickness difference negate any higher density? The cost is about the same between the two, so that's not a factor; just wondering which would be more effective?

that's interesting, I didn't see that difference when i was looking at them for my build. Given that it's around a 7% difference there's no real advantage to using the 70mm batts. if it was a different product and came in at 30kg/m3 then it could be worth it. You're better off going with the 110's which means you have a wider cavity, wand that is what lowers the resonant frequency. The insulation is there as a damper for the 'spring' in MSM walls so making the spring around 40% narrower (70mm batts) and raising the resonant freq, but only gaining a 7%increase in your damper isn't worth it.

Birdsteeth wrote:

Has anyone ever done a combination of inside-out walls with normal walls?

I also thought of doing this in my build but didn't for reasons that were explained to me. If you build all your walls inside out you then have flexibility with how much absorbtion and what type you put in the cavity. You can also seal up sections and make parts in to helmholtz resonators pretty easily. You can also just leave out the insulation if you want less damping for the room. If you go with half-half and then decide it's too 'live' in the room, you then have to build all your traps and hang them which is a lot more work than just putting insulation in the cavity. You'd be surprised at how large a section of wall you can lift up in one go either by yourself or with another pair of hands. I was able to lift my side walls by myself, approx 2.4m high x 4m long, by myself once i'd raised and propped them at around 1200mm high using a 4WD high lift jack. The end walls were 2.4 high rising to 3.3 in the center and around 5.5 m wide I did the same way but with another person which wasn't easy, but we got there. Three people would have been better for those :roll: all the best, Steve

Tracking down density specs for Australian insulation supplies can be a bit tricky. I couldn't find the specs for Soundscreen anywhere. Bradford only list density figures for some of their products like Ultratel and Supertel. Anyway, I happened across this today: http://www.insulationindustries.com.au/ ... siteis.pdf Might prove useful. It would be nice if all insulation manufacturers could publish a simple product comparison chart like this.

So, I put in my order for 150m2 (55 bags) of the Bradford Soundscreen batts, called the company to check stock and delivery times and they said 'yep, no problem they'll be there in a week'. So I paid for them (about $2000) only to be called today to say that there was an 'admin error' and that they don't deliver to Perth, even though you have to put in your postcode to even get a price! Then, they tried to tell me that it actually was available in Perth but it was $57 a pack, not $33 that was on their site and that I paid for. So, they basically stuffed the price up and then wouldn't cop the mistake and honour it. Sigh.... Anyway, I started looking for similar densities in other brands that were available in WA and I found that Earthwool do a 90mm, 27kg/m3 batt that's available at Bunnings for around the same price per m2. Has anyone used it? Sam.

Birdsteeth wrote:

So, I put in my order for 150m2 (55 bags) of the Bradford Soundscreen batts, called the company to check stock and delivery times and they said 'yep, no problem they'll be there in a week'. So I paid for them (about $2000) only to be called today to say that there was an 'admin error' and that they don't deliver to Perth, even though you have to put in your postcode to even get a price! Then, they tried to tell me that it actually was available in Perth but it was $57 a pack, not $33 that was on their site and that I paid for. So, they basically stuffed the price up and then wouldn't cop the mistake and honour it. Sigh.... Anyway, I started looking for similar densities in other brands that were available in WA and I found that Earthwool do a 90mm, 27kg/m3 batt that's available at Bunnings for around the same price per m2. Has anyone used it?

what a pain in the arse! sorry to hear that buddy :roll: That's a pretty bloody hefty price difference as well :evil: I believe Earthwool is a rock-wool-type product and not fibreglass. At 27kg's/meter it's too light. It needs to be more like 50kg's/meter for rockwool unfortunately. all the best, Steve

Ah crap, of course! Thanks Steve, I would've thought density is density... Gee the building materials industry is misleading. I put the call out on Facebook and a couple of tradie mates are looking for a good deal on the Bradford batts, I'm trying to not wear out my welcome by asking favours.

yeah, I did a lot of looking around and Bradford was the only suitable product I could find. With the exception of Fletcher's FI32 semi-ridgid, which is what I used for internal control room treatment. It's about double the price of Soundscreen however, so that's why I only used it where I realy needed it. all the best, Steve

I'm finding it extremely hard to find a company that'll supply Bradford insulation in Perth and I'm not sure why, the price seems to double whenever I'm sourcing it online and local suppliers don't stock the SoundScreen batts. I've got a builder mate who can get me the Fletcher stuff though, are the Pink Acousti-Therm HD R3.1HD batts okay or will I need the Pink Sonobatt Premium R3.0 batts? Man, I swear this'll be my last bloody insulation question!

Birdsteeth wrote:

I've got a builder mate who can get me the Fletcher stuff though, are the Pink Acousti-Therm HD R3.1HD batts okay or will I need the Pink Sonobatt Premium R3.0 batts? Man, I swear this'll be my last bloody insulation question!

Either should be good but the Premium will be best at 32kg/m. The HD says they have a nominal density 0f 24-32 kg/m. Does the density change as you get higher R values with those? or does it mean they don't know what density it is from bag to bag :shock: maybe give fletcher a buzz and check. all the best, steve

The insulation finally arrived (after the most hassle I've ever had dealing with a purchase) and it's started going in. The Fletchers 32kg/m3 stuff is pretty nice to use, not too itchy and easy to cut with a Stanley knife. I suppose I have to cover the exposed brick pillars with batts as well? Close to framing up now, it's starting to get exciting again!

Birdsteeth wrote:

The insulation finally arrived (after the most hassle I've ever had dealing with a purchase) and it's started going in. The Fletchers 32kg/m3 stuff is pretty nice to use, not too itchy and easy to cut with a Stanley knife. I suppose I have to cover the exposed brick pillars with batts as well? Close to framing up now, it's starting to get exciting again!

good to hear mate (not about the hassle though). Yeah, it's easy to use isn't it 8) I didn't cover the pillars in my build as it would've meant losing floor space and making the cavity about 220-250mm wide to get enough space between the pillars and internal walls. I figured that the pillars being solid double brick would make up for the fact that they don't have any damping on them. Stuart may have some definitive answers with maths on that, but I think you'll be okay with out covering them. Off topic, but there's a free dowload of a photo shop type program called photo pos pro. I used it a lot during my build thread to re-size and rotate pics whe needed for uploading. good to see you getting some build time in mate. keep us posted. all the best, Steve

Yeah the photo thing's weird, they're up the right way on my iPhone and iPad.

I think the forum has a limit on pixel width and height for pics. It could be that it's roatating them on upload to fit the pixel limits. not sure about that though. all the best, steve

Yeah the photo thing's weird, they're up the right way on my iPhone and iPad.

Maybe you are holding your iPad and iPhone sideways????? :shock: :( It would REALLY help if you could fix your photos: rotate them correctly, then edit your post with the updated versions...

I suppose I have to cover the exposed brick pillars with batts as well? Close to framing up now, it's starting to get exciting again!

It's not critical, but if you can spare the space (and the money) to do that, even if it is a thing layer, then yeah, it would be worth while. The main purpose of insulation in wall cavities is to damp the various resonances going on in there, including the standing waves that could form across the cavity, between the parallel surfaces. So even if you could fit in a bit of ordinary "pink fluffy" in front of the pillars, rather than entire batts, it would be good. - Stuart -

A bit late on the insulation front, but I got FI 32 through a WA firm in Canning Vale at a good price http://www.visualinteriors.com they may have other products you need later on. I also got ACOUSTIC suspended ceiling tiles via VI. Even though I'm in VIC, they arranged for local pickup as well. If anyone knows of local sources of low NC Air Vents and grilles I'd love to know. BTW l-o-n-g time lurker, with a few studio builds managed, and about to DIY a home listening room in my retirement.

I think I've fixed the photos?

I think I've fixed the photos?

:thu: :) - Stuart -