SIMO Studio - Construction Phase

you should mud the screws and the joints...but that wall is going to be heavy as hell, how do you intend to lift it in place?

Hi Brien, I know ! it's VERY heavy indeed ! … the problem is that I'm doing the build on my own and to lift and hold in position the sheet rock whilst screwing it to the stud frame is quite difficult and I'm not sure if I would do the job as accurately as doing it having the frame on the floor. :oops: This is my first finished wall and for this time I managed to recruit 3 friends of mine to come around to rescue me on Saturday, so (I hope) in four we "should " be able to lift it in place. Then, if it proves to be too hard a job I'll think of an alternative…perhaps having the stud frame at circa 45 degrees (resting onto something like a pedestal / scaffold-ish-thingy)… a bit more tricky for me to install the sheet rock but less hassle to push the finished wall fully up right…. we'll see how it goes with this first wall. Have a great day Ciao Simo

Hi there, I was looking around for a contact cement / adhesive to attach the insulation on the back of the plasterboard sheets on my inside-out wall costruction...and I just found this product: http://www.screwfix.com/prods/42076/Sea ... ive-2-5Ltr What do you reckon? Any other suggestions / alternative solutions? Simo

Hello! Here's a little update of what's been happening around here: - caulked joints and screws of first plasterboard (Firestop) layer - second plasterboard (Soundblock) layer installed…and caulked - insulation glued with contact adhesive (Very smelly!) - …and time for lifting ! (we actually managed in two… nice to have friends bigger than me) - wall bolted to the concrete floor, with 15mm neoprene rubber strip under it and with rubber washers (to minimise vibrations from transferring from the bolt to the stud) made out of rubber strip off-cuts and then cut their depth in half

... and onwards with the second wall (front of Control room) That's all for the moment Until next time… Ciao and Be well ! Simo

Hi, ...still me :) Quick question. My next wall will be the rear CR wall, where I need to pass the electric cable from the outside of the outer construction to the inside of my inner leaf (to connect it to a fuse box). As I'm building the wall on the floor, I can easily seal the outer leaf where the cable penetrates it, from both outside and inside (as at this stage the inner leaf wall assembly is still laying on the floor). Then I can pass the cable through the plasterboard (screwed on the back of my stud wall) and SEAL all around the cable…. …so at this point everything is totally sealed - fine ! Then, when I start lifting the wall up I would have to somehow pull the cable from the outside in order to shorten its length as the wall goes up and consequently closer to the ("inside face" of the) outer leaf. My problem is: How do I maintain the assembly sealed in the gap between inner and outer leaf (which will probably be compromised by me pulling the cable through)? I'm asking this because when the inner wall will be in its correct position (i.e. 10cm from the outer wall) I won't have access to the "points of penetrations" to re-seal them (?). Of course, I can always re-seal properly the penetrations on the outside of the outer leaf and on the inside of the inner leaf… but I'm not sure if that would that be enough? Any thoughts / suggestions ?? Really hope to hear from you very soon about that !!! Thanks a lot as always ! Have a nice week end Ciao Simo

sealing it from the inner leaf should suffice. one thought - you could make a small plate from neoprene and have a friction fit over the cable up to the wall and seal all around that.

Thanks so much Glenn, much appreciated ! Great idea - I'll do that. Have a nice day Simo

Hi there all, it's been a while since my last post…. been busy between work and family, but I have managed to get ahead a bit. Here are some pics of what has been going on: Trimmed the wall by 5cm to get it down to 2.4m, to match the length of the plasterboard sheets: Firestop layer goes up: Soundstop layer next: Main cable gets fed through the plasterboard layers, with a "rubber plate" on the outer wall and on the back of the inner wall: …and sealed: Forth wall up (between Control room and Live room): .....to be continued ....

…and here is where I am at: Today I've been caulking, caulking, caulking (no pics of that at the moment though) Next I will be doing the angled front left wall (coloured in red) and the bass traps on the rear corner. My question is: Would I get any benefit from having them resting on a rubber strip (as I've done on the other walls), or wont this be necessary in your opinion? Many Thanks Ciao ! Simo

Would I get any benefit from having them resting on a rubber strip (as I've done on the other walls), or wont this be necessary in your opinion?

For what purpose? Just for sealing? Or for decoupling? You can only decouple a wall with neoprene underneath it if you also use some form of isolation on the bolts that hold the wall in place, and if you do your calculations correctly and only tighten the bolts so that they do not over-compress the neoprene. Compress it too much, and it flanks, so you gained nothing. The neoprene has to be compressed to the optimum range when the room is finished: if not, then you waste a lot of time, money and effort for no purpose at all, if your objective is decoupling the walls. But if you just want to seal them, then you don't need isolated bolts, and you can tighten them any way you want. So assuming you are just planning to use neoprene for sealing, not for decoupling: The bass trap frames do not need sealing if you are going to do superchunks or some other form of pure absorptive treatment, but if you are going to do a tuned treatment (like slot walls or some such) then they do need sealing. But what concerns me is that angled wall thing on the right, highlighted in red: What is that? Is that going to be a slot wall or something? You cannot put drywall on that, since it would create a third leaf, so I'm assuming it will be a slot wall? If so, then yes, it does need sealing. If not, then what are your plans for that? - Stuart -

Hi Stuart, Thanks for your response and advise ! The reason why I put rubber strips under the walls is because the concrete floor is quite uneven in certain areas, so it is just for sealing (Not for Decoupling). Yes, the angled wall (highlighted in red) IS a slot wall. You can see the plan on the 1st page (towards the bottom) of this tread. Ciao Simo

"You cannot put drywall on that, since it would create a third leaf," To be fair, it is already a modified mass/air/mass (a new term I learned) applied directly to an existing residential wall sheathed on both sides with a decoupled interior mass. The existing wall/structure has an exterior/studs/interior panels. This get's called a two leaf (a double sided single frame assembly) so the additional insideout walls create the multiple air spaces we all try to avoid. Certainly we try to avoid if possible, but everything matters so it may not have been possible to avoid. Just an observation,

Thankyou very much for your observation Brien ! …just a quick note tough: in my case the existing wall/stucture has not an "exterior/stud/interior panels" but it's made of concrete blocks with concrete render both on the inside and on the outside…. so I hope in my case the additional insideout walls will not create the multiple air spaces you describe on your observation ??!!? Simo

in my case the existing wall/stucture has not an "exterior/stud/interior panels" but it's made of concrete blocks with concrete render both on the inside and on the outside….

Exactly. That's why it would have been a third leaf if you would have put drywall on that angled frame. But since it will be a slot wall, then you don't have a problem.

so I hope in my case the additional insideout walls will not create the multiple air spaces you describe on your observation ??!!?

Correct: You only have two leaves and one air gap. Adding the slot wall does not really create a third leaf, so you'll be fine like that: But you do need to ensure that the cavity behind the slats is sealed. In order to work correctly, the slot wall must be sealed. - Stuart -

Hi there, Hope you are all well ! I'm building the splayed wall on the right hand side of the CR, which will be a slot wall. My question is about the area at the right of the speaker soffit …. A) shall I close and seal the cavity where the soffit frame and the splayed wall meet and put some hangers in there ? ….or…. B) shall I leave the entire cavity as it is (empty), essentially just making a deeper slot resonators ? Thanks a lot in anticipation Have a great Easter !! Ciao Simo

Hi simo, B is my choice. Referring to one of John Sayers SKP's for soffit mounting and this page, http://johnlsayers.com/Recmanual/Titles/Acoustics2.htm on the HELMHOLTZ RESONATOR, it looks like it should be a sealed cavity. -charlie

Hi Charlie, Thanks for your reply! Perhaps I didn't managed to explain myself clearly :-) sorry… I was definitely planning to seal the frame directly behind the right speaker soffit (as kindly posted by you)…. my design though differentiates from your attached pic in that I've got a "reinforcing frame" going from the straight inner wall to the splayed slat wall (let's call it "Z"). If I place a gyprock sheet just there, I would in fact be left with 2 cavities ("A" and "B"). Thus, I was wondering if it would be worth to have hangers in the sealed cavity "A" (in order to have a bit more low frequency absorption in the room) and have a smaller sealed cavity "B" (being the slot resonator's cavity) …or… not having the gyprock sheet at all attached to the "reinforcing frame Z", thus having a "bigger" slot resonators (as per your attached pic). Hope I made myself a little bit more clear :-) Thanks again ! Ciao Simo

Simo, I am no expert, just an avid reader of this forum trying to refer you to some of the documentation I have found relating to your situation. I would wait until one of the known experts on the subject chime in. Will be interested in seeing what they say.... good luck -charlie

Hey Charlie, thanks a lot for your documentation man, much appreciated !….I'm not expert either :D Let'sjust wait and see if one of the expert finds the time to have a look at this. All the Best ! Simo

cavity A should be open to the back of the speaker soffits and yes, putting hangers there would be good. the B cavity behind the slats needs to be sealed.

Glenn, Great, thanks so much for your explanation! …just to make sure before I proceed building it…is this what you mean ? : and then place hangers in there Sorry to be a pain :oops: , but I need to clear my head and ask one more question: Having hangers beside just the right speakers (as I haven't the same space on the left hand speaker soffit) won't this produce an "unbalanced sound field" (being the right side of the room more absorbent at low frequencies)? … or … giving that low frequencies are non-directional by nature will mean that it does not matter where the low freq absorbers are positioned within the room (so in practice I'll be fine :D)? Ciao Simo

yes it's somewhat unbalanced but if i'm correct - this is what you have to work with and it shouldn't be problematic. so yes, go ahead with the additional absorption with the hangers (the new construct looks right) and make sure the two soffits have equal absorption.

Great, Thanks so much for your help Glenn, really kind of you !! All the Best Ciao Simo

Hi there! Hope you are all well !! First of all: Glenn, you said "make sure the two soffits have equal absorption"… sorry but this makes me a bit confused… If the area named "A" on previous pic (which I was planning to fill with hangers) will then be part of the right soffit (being it open to its rear), won't this make the right soffit MORE absorbent than the left one (which has NO hungers behind it)? Really sorry for not getting it (and keep annoying you) :oops: ! …but …. Help!! It's not that I don't trust you (actually it's completely the opposite)…it's just that I would like to understand things and not just execute them ! :) Also, about Hangers….. Since that I can't find homasote here in UK (for the core of my hangers), when I was looking for other soft fibreboard sheets the only alternative was the fibreboard laminate flooring underlay (which it's just 5mm). It doesn't give specification about the Kg/m3… what I can say is that It's very soft, so that you can actually tear it with your hands! What do you think? here is the link: http://www.wickes.co.uk/fibreboard-unde ... vt/201508/ Do you know what else I can use as an alternative for the core of my hangers? Perhaps thin (4mm or 6mm) MDF? thin (9.5mm) Plasterbord sheet? Many Thanks Simo