Garage -> Studio Build

Paulus87 wrote:

It's just an extra pre-caution. You're using treated lumber but even that can rot out if it soaks up enough moisture, I saw this first hand on my build where there was an exposed sole plate end that I didn't see until 3 years later and water got in there and it's pretty compromised already. If you can, get some sort of rubber to put on the bottom faces of the sole plates, it will fill in any little imperfections in the concrete/wood where air can leak through, or if not just caulk the bottom faces really liberally before erecting the frames. Then caulk all the way round the perimeter to seal it to the concrete. Paul

Ok, so I was originally going to use a sill sealer like this... https://www.homedepot.com/p/Owens-Corni ... /202080947. It does an adequate job of sealing the space under the sill plate, but it doesn't do anything for moisture build up. I was also going to caulk the shit out of the sill plates once they were bolted to the cement. But if you're suggesting I put a layer of plastic down first, wouldn't I then be caulking the sill plates to the plastic and not the cement?

Jag94 wrote:

Paulus87 wrote:

It's just an extra pre-caution. You're using treated lumber but even that can rot out if it soaks up enough moisture, I saw this first hand on my build where there was an exposed sole plate end that I didn't see until 3 years later and water got in there and it's pretty compromised already. If you can, get some sort of rubber to put on the bottom faces of the sole plates, it will fill in any little imperfections in the concrete/wood where air can leak through, or if not just caulk the bottom faces really liberally before erecting the frames. Then caulk all the way round the perimeter to seal it to the concrete. Paul

Ok, so I was originally going to use a sill sealer like this... https://www.homedepot.com/p/Owens-Corni ... /202080947. It does an adequate job of sealing the space under the sill plate, but it doesn't do anything for moisture build up. I was also going to caulk the shit out of the sill plates once they were bolted to the cement. But if you're suggesting I put a layer of plastic down first, wouldn't I then be caulking the sill plates to the plastic and not the cement?

The sill sealer is fine, you could use that. You still bolt them down into the concrete, and yes just seal them to the plastic. If you prefer not to use the plastic under the frames then that's your decision, are you building this to code? If so perhaps get advice from a local inspector or trusted builder? Paul

Paulus87 wrote:

The sill sealer is fine, you could use that. You still bolt them down into the concrete, and yes just seal them to the plastic. If you prefer not to use the plastic under the frames then that's your decision, are you building this to code? If so perhaps get advice from a local inspector or trusted builder? Paul

I think I'll go with the plastic. It'll be a pain in the ass, but I'd rather prevent the possibility of wood rot, even if it's not likely to happen. That coupled with the sill sealer, plus caulking all sides of the sill plates should be pretty good. Is there a specific type of tape that works best for securing the plastic to either cement or the sill of the exterior leaf? Thanks for the input.

Jag94 wrote:

Paulus87 wrote:

The sill sealer is fine, you could use that. You still bolt them down into the concrete, and yes just seal them to the plastic. If you prefer not to use the plastic under the frames then that's your decision, are you building this to code? If so perhaps get advice from a local inspector or trusted builder? Paul

I think I'll go with the plastic. It'll be a pain in the ass, but I'd rather prevent the possibility of wood rot, even if it's not likely to happen. That coupled with the sill sealer, plus caulking all sides of the sill plates should be pretty good. Is there a specific type of tape that works best for securing the plastic to either cement or the sill of the exterior leaf? Thanks for the input.

There are certain tapes designed for the job, try an online hardware store or insulation supplier, or passive house building website etc... Paul

DanDan wrote:

I hope someone with local build experience chimes in. Many of the words you use are unknown here. So I can only speak on Acoustic issues. The various harder insulation, Poly this and that, are thermally let's say 3 times more effective than fibre. Here a typical 4" board replaces a foot of fibre. Our houses have BER thermal certs which affect their sale value. But these boards have pretty much zero acoustic effect or benefit. Also here, and may not apply to you at all, warm layers can cause taxi aéroport problems with condensation, mould, rot. So hopefully a practical or professional builder with USA Code and other knowledge will help out now? Have you got Rod Gervais' book, Build it like the Pros?

I do remember vaguely reading on this forum that using it in this manner increases LF isolation.

It's been quite a while since I did an update, but i've been hard at work. This build is taking a lot longer than I anticipated, and I'm severely over budget. But, as they say, if you're not over budget, you're doing it wrong. Well, if they don't say that... I just created a new saying. I haven't been as good as I should be with taking pictures, but I'll post what I have. I left off with building of the wall frames. I hadn't placed them or bolted them in yet... I still had a few things to do before I got to that. First up, was widening the existing entrance doorway. It was a 28" x 76" door - which if you've ever tried to carry anything larger than a grocery bag through, you know that's just too damn small of a doorway. My goal was to open up the doorway to make way for a 36" x 80" door. I had to re-frame the doorway, and beef it up to handle the new (not yet purchased/built) super-door for the exterior. If you remember, I had to remove some overhead ceiling joists that were original "old-growth lumber", so I cut them to size and added them to create new King, Queen, and Jack studs. i then built an even better/stronger header than the joke of a header that was there to begin with. Hopefully you can see the results in the pictures below. Next was cutting the exterior stucco to match the new exterior door frame. I thought this was going to be difficult, but I bought a new Makita angle grinder, and a carbide cutting blade, and it took about 20 minutes and it was done. And not only did it cut easily, but it was smooth, clean, and easy to manipulate. I was extremely happy and surprised by the end result. I am still a long way from installing new door jambs and doors, but I was extremely happy that this part of the build was relatively simple. Next up was cutting massive holes in my exterior leaf to install intake/exhaust ductwork for the ERV. This was anxiety inducing simply because I had spent months adding mass to the exterior leaf, and now I'm putting MASSIVE holes in it! However, I think I did alright. I have a bosch bulldog, which is a fantastic hammer drill that made putting holes in the stucco super easy. Once the 8" hole was made, I caulked the perimeter and stuck some backer rod to the still "wet" caulk. Once it dried, I inserted the wall penetration hoods, and caulked the perimeter. I then went on the inside, and caulked the $hit out of the inside as well. The end result not only looks good, but I'm hoping will suffice in terms of maintaining my isolation.

Next was installing the ductwork that would go in between the inner leaf and outer leaf. This is one reason I didn't place the wall frames yet. I needed to be able to install these ducts, and not having to maneuver in between the leafs made this very simple. The vertical 8" rigid ducts are decoupled from the hoods with 8" flex duct. And the same will be done when penetrating the interior leaf. Rod was very adamant that all of my flex duct runs were very short, and he approved of this design. I used mastic, zip ties, and tape to secure the flex duct to the rigid duct. I applied very liberal amounts of mastic to all of the rigid duct to seal any and all seems in the rigid duct. There will be NO leaks in this system. Once the ducts were in, it was time to place the frames and bolt them in place. I don't have any photos of this, but... well... I did it. lol. But before I put them in place, I filled the stud bays of the exterior leaf with pink fluffy insulation. Next was cutting, and assembling the rafters for the interior frame. I had drawn everything up to the exact inch in sketchup, so getting the measurements for this was quite simple. I laid out a couple of pieces of plywood to create a deck, and cut template pieces of rafters and installed blocks to hold them in place. Now I could easily cut and align the rafters to the exact angles and lengths to join them together.

Once the rafters were installed, it was time to start filling the frame with insulation. I had to add a layer of insulation in between the interior and exterior leafs, and then another layer inside the interior leaf. I'm still doing this to the ceiling, as I need several layers to fill the gap. I installed the mini-split condenser unit outside, and ran the electrical to a disconnect box myself. I hired an HVAC company to run and connect the refrigerant lines (although I wish I ran the lines myself, and just called them to connect it all when I was ready, as it cost me WAY more than I was anticipating). The interior unit won't be installed until the multiple layers of drywall are up. The next part was installing rafter ties to the rafters (which are what are going to be holding my ceiling OSB and drywall). They are now in, and I'm currently filling the gaps with insulation. I am just about ready to start installing the first layer of OSB. My only hang-up is my electrician. He has been difficult to get ahold of, and I can't install the first layer until I get the electrical set up. Luckily I'm about a week away from that anyway, but it is causing a bit of stress. I will reach out to more electricians tomorrow to see if I can get a move on. However, I liked this original electrician because he has done work in studios before, and is the only electrician I have spoken with that understand what a studio needs. I wish I knew enough about this to do it myself.

Thanks for posting this update; it's looking good and your attention to detail / method is an inspiration.

This build is taking a lot longer than I anticipated . . .

Yes indeed - If I had five quid for every time I'd thought that . . . Easy for me to say but it seems to me like you're making fairly rapid progress.

I haven't been as good as I should be with taking pictures . . .

I've found that when I'm concentrating properly on one or other aspect of the build, I almost invariably forget to photograph the process. I'm looking forward to seeing more when you can post it. ATB John.

It's all looking good so far apart from one thing that I want to check with you: (sorry if I already asked this, I can't remember) Have you got pink fluffy insulation pressed up against the roof deck between the outer leaf rafters? Paul

John Steel wrote:

Thanks for posting this update; it's looking good and your attention to detail / method is an inspiration.

Thanks for that, John. My wife thinks I'm crazy and I'm being too particular about the small stuff. I keep telling her there is no way I'm spending this much time and money and half assing it.

I've found that when I'm concentrating properly on one or other aspect of the build, I almost invariably forget to photograph the process. I'm looking forward to seeing more when you can post it. ATB John.

Yeah, I'm exactly the same way. Plus I'm usually busy making and fixing mistakes that by the time I finally get it right, I'm too pissed off to remember to take pictures. haha.

Paulus87 wrote:

It's all looking good so far apart from one thing that I want to check with you: (sorry if I already asked this, I can't remember) Have you got pink fluffy insulation pressed up against the roof deck between the outer leaf rafters? Paul

Hi Paul, yes, there is insulation in between the rafters on the underside of the outer leaf. I wouldn't say it's "pressed", it's just sitting there nice and fluffy like all the rest. Also, remember that drywall is in between the rafters (and backer rod and caulked). So the insulation is up against that. It is a hot roof, so there are 2 layers of insulation on top of the roof under the shingles, but above the OSB roof deck.

Jag94 wrote:

Paulus87 wrote:

It's all looking good so far apart from one thing that I want to check with you: (sorry if I already asked this, I can't remember) Have you got pink fluffy insulation pressed up against the roof deck between the outer leaf rafters? Paul

Hi Paul, yes, there is insulation in between the rafters on the underside of the outer leaf. I wouldn't say it's "pressed", it's just sitting there nice and fluffy like all the rest. Also, remember that drywall is in between the rafters (and backer rod and caulked). So the insulation is up against that. It is a hot roof, so there are 2 layers of insulation on top of the roof under the shingles, but above the OSB roof deck.

:thu:

Insulation has been installed in between the rafters in the ceiling. I'm just waiting on the drywall lift to start installing the first layer of OSB. One thing I forgot to mention about the mini-split condenser. Most condenser units require a clearance of minimum 6ft in front of the unit so that when the fan is blowing, the air has enough room to flow properly. Since the garage is just 3ft away from the property line (code in these parts), after mounting the condenser unit, there was only about 1ft clearance in front of the unit. I found and purchased a "wind baffle", which are typically used for areas with high wind, but also can be used to deflect the air upwards instead of straight at the fence (which would then be bounced back towards the unit causing problems).

Update time. A lot has happened in the last couple of weeks. The drywall lift came, so I was able to start with the first layer of OSB on the ceiling. That lift was 100% worth every flippin penny. It made the install of OSB on the ceiling so damn easy. I caulked the perimeter of the ceiling, and then started install of the south wall. I had to wait for the electrician to come to figure out the routing of the electrical inside the north wall before I could install the first OSB layer. The electrician came and we got the whole thing sorted. He was super helpful, charged me very little for the small amount of work he did, but was very gracious with is advice and his time. I really lucked out with him. Once I finally got all the electrical routed in the walls, I filled last bit with insulation, and was able to finish installing the OSB as the first layer of sheathing on my inner leaf. This meant getting very specific and accurate measurements for the electrical and HVAC penetrations in the walls. I made a jig for this brand new Dewalt router I bought which has been incredible. The jig allowed me to cut perfect holes in the OSB for the ductwork. Once the North and South walls were done, I caulked them, and then put up the layers on the east and west walls (and caulked the perimeters). The other thing the router was great for, was cutting the OSB around the door opening. I installed full panels of OSB, and then used a trim router bit, which is a bit that has a wheel on the end of it that allows me to cut along the rough opening of the doorway, without cutting the rough opening. It made for a PERFECT cut around the doorway, and took about 3 minutes. I couldn't be happier. Once the entire room was covered in OSB, it was time for the first layer of drywall with green glue on the ceiling. I have waited for this moment for 6.5 months. First was loading up with green glue. The company recommends 3 tubes per sheet of drywall. I've seen a LOT of people comment you can get away with using 2 per sheet... but after all the work I've done, I decided 3 tubes per sheet is what I'm doing. First layer of drywall on the ceiling done... After backer rod and caulking the perimeter of the ceiling, I installed the first layer of drywall with green glue on the south wall, plus one sheet on the north wall (I ran out of time and daylight!). Tomorrow I hope to finish the north wall, and the west wall, and the next day finishing up the first layer of drywall on the east wall. I'm hopeful that by the end of the week I will have the entire 2nd layer of drywall (with 2nd layer of green glue) up.

I have a lot to update, but I'm not quite ready to do it yet. Instead, I have a question. I'm building custom door frames using 6/4" poplar, and will be building a beefy door. I found a solid core fire rated door at home depot for $75, and it's SUPER heavy. At least 100 pounds. I also want to add a sheet of 3/4" MDF to this door to add even more mass. I was reading THIS thread (4th post down), and Gregwor mentions gluing the MDF to the door slab. What kind of glue should I be using? Regular wood glue? Liquid nails construction adhesive? Green glue!? (I know green glue is not an adhesive, but would it not work in this application?). Any guidance would be appreciated!

screw on the MDF and consider the option of adding some MLV or green glue between the MDF and door to add some damping factor. otherwise, just screws and construction adhesive will work. hopefully you're planning on using some cam-hinges to lift the door off the threshold seals, and a proper slow-closing mechanism to ensure safety when operating a 200lb door...

gullfo wrote:

screw on the MDF and consider the option of adding some MLV or green glue between the MDF and door to add some damping factor. otherwise, just screws and construction adhesive will work. hopefully you're planning on using some cam-hinges to lift the door off the threshold seals, and a proper slow-closing mechanism to ensure safety when operating a 200lb door...

Hey Glenn, Thanks for the tips. I have a bunch of green glue left over, so I could use that. I think a buddy has some left over MLV from his project, so maybe I could use that as well. If I use the green glue though, I would just use screws to hold the MDF to the slab? I bought heavy duty commercial grade ball bearing hinges, and I'll be installing 6 of them per door. And yes, I am going to purchase a commercial grade door closer as well.

Update time. It's been about a month since I last updated, but that's just because I've been working my ass off to get this thing finished. I still have a long way to go, but I'm getting close. I'm making good progress and more importantly, I'm really happy with the way this thing is turning out so far. I'll explain why as I go. Before I get started, I just have to share this exchange with my wife. I was installing the first layer of OSB in the interior leaf and she walks in to see the progress. Keep in mind this is about month 6 or 7, and I had been out there working on this thing nearly every day for those 6-7 months. So she knows what I've been doing, even if she doesn't understand it and constantly asks... "is this really necessary?". As I was putting up the last piece, she says... "Once you're done and the room is finished, no one is going to know all the stuff you did under the drywall." I looked at her, nodded, and continued. Then I said... "I'll know." It's been a wild ride. But we're not done yet! Anyway - progress update. Next up was continuing the first layer of drywall on all 4 walls. I used a dremel with a drywall cutting bit and circle cutting jig to cut the wholes for the HVAC flex ducts penetrating through the north wall. Once the first layer was in, I backer rod and caulked the entire perimeter, and started on the 2nd layer. Again, I backer rod and caulked the perimeter. This room is sealed tight. The amount of caulking I used on this project is ridiculous. But I'm really hoping that it'll be worth it. Also, I think I used about 120+ tubes of green glue for this whole project. I bought way more than I needed. I somehow way over estimated, but I was able to sell the leftovers for about the same price I bought it for, so no harm done. I did 3 tubes per sheet of drywall. This is what Green Glue recommends, although they say 2 tubes is fine, and even 1 tube will do something, but you get more isolation with the more you use. While reading about green glue, it turns out that if you use more than 3 tubes, you continue to improve isolation. They just set the recommendation at 3 because they felt like that was a reasonable amount, instead of just saying, buy as much as you can afford... lol. Again, I'm hoping it was worth it. Next up was tape and mud. I have never taped and mudded an entire room before, I've only patched holes, so I was very hesitant to do this myself. I had 3 different contractors come give me a quote to do the room, and the prices ranged between $600 - $1200. As I'm already over budget, I decided to tackle it myself, and for less than $100 in materials, I went at it. I watched a series of videos by a guy on youtube (who has hundreds of videos and really shows the details for these types of things), and it really helped. It took me about a week to get all 3 coats on, so while it took me a lot longer than a pro would have taken, I was EXTREMELY happy with the results. I sanded the entire room, and applied the primer coat. I learned that there is a different type of primer for brand new drywall/mud & tape (never been painted), and when I first painted it, it was extremely streaky and you could see all the mud under it. I put that first coat on at the end of the night, so I let it dry over night. When I came back in the morning, I was SHOCKED at how well the room looked. It was perfect. I was really happy and quite proud of the corners of the room. They came out as close to perfect as they could get. Too bad they're going to get covered up with super chunks! Next up was painting the color of the studio. My wife wanted a light color because the room is kind of small, but I wanted a "warm" color. I found this color that has a brown/red/orange mix to it, and I really like it. I can't wait to see it with warm track lighting overhead.

Next up was the floor. I put down a 6mil plastic to cover the concrete, and then a cork underlayment. As for the floors - oh boy. I actually bought a floor, and brought the floor with me to home depot to pick out colors. The floor was pretty dark, and I thought I liked it in the store. When I started laying it out in the room, I HATED it. So I packed it back up (luckily I only opened one box, and didn't make any cuts), and I brought it back. I picked a lighter color that I really like. I don't think I have any pictures of the floor yet, but you might see it in some of the pictures later on. Next up was the door frame/doors. I have been stressing over this, because at this point, this could make or break the whole studio. Someone posted a pdf on how to build studio doors by John Brandt (I can't remember who), but it had a LOT of useful tidbits in it. The first of which, was the topic covering the gap between the inner/outer leafs at the rough framing of the door opening with a specific type of rubber.. I hadn't thought anything about this until I read it, and it made sense. So I bought the rubber stuff, caulked both frames, and installed it. It looks clean, and now the rough frame is ready for a door jamb. I went to my local lumber yard and bought 6/4" poplar. I measured 4 times, and cut the frame to size. I used pocket holes to construct the jamb around the door. I ripped 1/8" and 1/16" spacers so that the door jamb would be EXACTLY the correct size for the door. One issue I had though, was the 6/4" lumber I used, was slightly larger than 1 1/4". I didn't account for this when making the jamb, so when I went to put the jamb in the door frame, it was SUPER TIGHT. I guess I framed my doorway so well, that I didn't leave any wiggle room. This could have been really bad if the frame wasn't perfectly plumb, square and level... but because of my extreme diligence, it turns out the rough framing was basically perfect. When I finally wedged the door jamb in place, the entire thing was already plumb. I didn't have to use a single shim. I couldn't believe it. I also primed and painted the jamb before I installed it. I didn't take any pictures of this, but you'll see it when I show the door. As for the door, I painted the interior side the same color as the room, and I installed a 3/4" MDF panel to the exterior side, and painted that side black. The I mortised the hinges using a router, and a door hinge template. It made the entire process SUPER easy. I was really nervous about the hinges, so I mortised the hinges on the door jamb about 1/16" bigger on both sides in case I needed a little play the door when hanging it. I had 2 buddies come over to help hang the door. The bigger/stronger friend held the door in place while I aligned and screwed in the hinges to the frame, and the other friend (who is a native Italian) just stood there telling us how bad of a job we were doing. I would expect nothing less from an Italian. I only screwed in the top and bottom hinge into the jamb, and then tested the door. I closed my eyes, and slowly closed the door, praying to the studio building gods that this worked. And holy $h!t the door closed perfectly. It didn't snag or rub on any part of the door frame. The top, bottom, and latch side of the door have a nearly perfect 1/8" gap, and the hinge side has a perfect 1/16" gap. I was shocked. I screwed in all the other hinges and laid on the ground thanking the heavens that it worked.

Next up is the construction and installation of my silencer boxes. I designed these a few months ago, and I knew the dimensions were "big", but I didn't realize HOW big until I actually constructed the damn things. They're HUGE! But that's the point, right? I had so much OSB left over, that I used those instead of MDF. Since these are going inside the room, and being mounted on the floor, i decided to make the extremely mass loaded. So they will be 3 layers, OSB>green glue>drywall>green glue>drywall... the same as my walls. I used pocket holes to assemble everything, and these things are really well built. Oh, my wife got me a pocket hole jig for christmas, and it's been absolutely wonderful. I love it. But now I have to build her all sorts of stuff with it. I guess that's what I get. I also got to use my home made router hole cutting jig again to make the holes in the OSB. I caulked all of the edges, and dry-fitted them in place in the room. I had to add some shims under them so that the hole that penetrates the inner leaf lines up with the hole in the silencer box. You can barely tell in the photos, and once everything is done and baseboards are in, nobody will know the difference except for me. I put the bottom two layers of drywall on first, accounting for the extra layers that will need to go on as I close the box up (after duct liner is put in). I caulked around the perimeter of the boxes, as well as the back of the box before I pushed it up against the wall, and screwed it in. Then I put added duct connectors to the two openings on each box, and added the top two layers of drywall. The next couple of days I'll be putting the side layers on, putting in the duct liner, and closing the boxes up. Next up I will be installing the door seals and door stops for the interior door. My exterior door has not arrived yet, but when it does, I need to go through the same process for that door as well (building the jambs, mortising the hinges, hanging the door, etc). My wife is due to deliver our first child in about 10 days, so my free time is going to be pretty limited, but I'll update what I can when I can.

excellent work! and good luck with the new family member!

Jag94 wrote:

Next up is the construction and installation of my silencer boxes. I designed these a few months ago, and I knew the dimensions were "big", but I didn't realize HOW big until I actually constructed the damn things. They're HUGE! But that's the point, right? I had so much OSB left over, that I used those instead of MDF https://sheetmaterialswholesale.co.uk/sheet-materials/mdf/. Since these are going inside the room, and being mounted on the floor, i decided to make the extremely mass loaded. So they will be 3 layers, OSB>green glue>drywall>green glue>drywall... the same as my walls.

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I used pocket holes to assemble everything, and these things are really well built. Oh, my wife got me a pocket hole jig for christmas, and it's been absolutely wonderful. I love it. But now I have to build her all sorts of stuff with it. I guess that's what I get. I also got to use my home made router hole cutting jig again to make the holes in the OSB. I caulked all of the edges, and dry-fitted them in place in the room. I had to add some shims under them so that the hole that penetrates the inner leaf lines up with the hole in the silencer box. You can barely tell in the photos, and once everything is done and baseboards are in, nobody will know the difference except for me. I put the bottom two layers of drywall on first, accounting for the extra layers that will need to go on as I close the box up (after duct liner is put in). I caulked around the perimeter of the boxes, as well as the back of the box before I pushed it up against the wall, and screwed it in. Then I put added duct connectors to the two openings on each box, and added the top two layers of drywall. The next couple of days I'll be putting the side layers on, putting in the duct liner, and closing the boxes up.

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Next up I will be installing the door seals and door stops for the interior door. My exterior door has not arrived yet, but when it does, I need to go through the same process for that door as well (building the jambs, mortising the hinges, hanging the door, etc). My wife is due to deliver our first child in about 10 days, so my free time is going to be pretty limited, but I'll update what I can when I can.

When I was very young I thought there was wood and there was fake wood. I didn’t know anything about how or why plywood existed but I knew there was a difference between it and real wood and I simply thought all fake wood was called “plywood.” Then my brother explained to me that there was a difference between normal plywood and particle board.

"particle board" tends to be light weight and easily damaged by moisture. plywood and OSB is much more dense. MDF is even more dense although there is some susceptibility to moisture.

Ok I have another electrical question that I'm hoping you guys can help me out with. I've been reading and reading and reading about isolated ground systems, star ground systems, etc. and I feel like i have this 98% correct, but that last 2% is just killing me... and all the threads I've read don't have the exact situation I'm dealing with. Most of the electricians that I have contacted aren't well versed in audio for studios, so while I've gotten a lot of great advice for general electrical, I'm not getting the info I need for a star ground system. A few important notes. I have a 200amp main service panel at the house. I am running a 60amp breaker off the main panel to a sub-panel in the garage (being run with #6 gauge wires), which is a detached garage. The ground and neutral are bonded together in the main service panel, but will NOT be bonded together in the sub-panel, because that's code. There are 2 ground rods at the main house (one bonded directly to the ground bus in the main service panel, and one bonded to the water pipes at another point in the house). There is a ground rod for the garage that will be bonded to the ground bus in the sub panel, as it is code for every separate building to have it's own ground rod. Right now there are 4 conductors running from the main service panel to the sub panel in the garage. 2 hot, 1 neutral, 1 ground. They are running underground in conduit. I built this space to not have any holes in the walls. All outlet boxes, switch boxes, sub-panel, conduit, etc. will be surface mounted to the drywall. My plan was to run EMT conduit from the sub-panel to each metal outlet box, and use isolated ground receptacles. The metal conduit and boxes would serve as the safety ground (as they are bonded to the boxes and sub-panel), and a THHN ground wire would be run in the conduit with the hot and neutral wires to connect directly to the ground pin on the receptacles. None of the receptacles will be daisy-chained. They will all have home-runs back to the sub-panel for the hot, neutral, and isolated ground wire. From what I understand, is for a star-ground to work, all of the isolated ground wires need to come back to a single common star point, i.e. a ground bus bar that is not bonded to the ground bus bar in the sub-panel, or the sub-panel itself. I was planning on installing a box directly under the sub-panel that is fed by PVC conduit (so it is not bonded to the metal sub-panel), and all of the isolated ground conductors would connect to a ground bus bar in this box. Here's where I'm unsure. I think I screwed up in that I should have run 5 conductors from the main service panel to the sub-panel (2 hot, 1 neutral, 2 grounds). One ground would go from the ground/neutral bus in the main service panel to the ground bus bar in the sub-panel, and the other ground wire would go from the ground/neutral bus in the main service panel to the box that contains a ground bus bar that is not bonded to the sub-panel. This would have all the isolated ground wires coming to a commons star point, and then being brought all the way back to the main service panel where it would be bonded to the ground bus bar, and then to the ground rod at the panel. But I only ran 4 conductors (due to a confusion/miscommunication with an electrician who I thought understood what was happening). So now, I don't know what exactly to do with the isolated ground conductors coming from each receptacle. 1 - Do I have them all join at a common star point in a separate box that is not bonded, and then splice into the 1 ground conductor coming from the main panel? Would that not defeat the purpose as now the isolated grounds are connected to the same wire that is bonded to the sub-panel ground bus? 2 - Do I just hook up the incoming ground conductor to the ground bus in the sub-panel and forget about the star-grounding thing all together? Do I use plastic boxes, PVC conduit, or other means to just run the electricity without isolating the grounds? 3 - Can I connect the ground wire that is bonded to the ground rod to the isolated ground bus bar, and leave the green ground conductor that is coming from the main service panel bonded to the ground bus in the sub-panel? Or does that ground wire that is bonded to the ground rod HAVE to be bonded to the sub-panel? 4 - Some other option I'm not aware of? Here is a picture of the inside of the sub-panel in the garage. In the lower left is the ground wire that is bonded to the ground rod just outside the garage. To the lower right are the 4 conductors (2 hot, 1 neutral, 1 ground) being brought in from the main service panel.

you have a single ground there? and it's connected to the main box ground bar? or the ground is to the grounding pole/pipe? so if you wire wall you outlets in the room with a star ground approach, you should be ok. would be wise to read up a bit on ground loops and avoiding them - in essence having your wires take one route rather than split route around the room will help in this regard. it's also important at this stage to consider what is "clean" (lowest noise, not induction, dimmers etc) side and which will be "dirty" (lighting, dirty outlets for non-audio purposes, etc) so the wiring is kept as consistent as possible. thus later if needed, you could insert some electrical isolation to reduce the noise in the electric.