Studio Build: Garage Conversion in Los Angeles

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Soundman2020
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Studio Build: Garage Conversion in Los Angeles

#61

Postby Soundman2020 » Wed, 2020-Oct-28, 00:31

There is a grounding rod right there at the panel connected with 4AWG stranded wire, and driven deep into the ground. There is a 2nd grounding rod at the front of the house that is bonded to the water pipes.
That's not such a good idea. That opens you up to ground loops, as you have two different ground points at possible different potentials. Generally, you only want one single ground for the entire building. Are there any signs of corrosion at the point where the second ground conductor is attached to the water pipes? If so, I'd be wary...

I would suggest that you hire a locally certified and experienced electrician to check things over, and tell you what is fine, and what isn't. Electrical codes vary wildly from place to place, even though they are all supposed to be based on the same thing. So get a local guy that is certified, license, or whatever they call it where you live, and get him to sign off on all the paperwork, even if you do the work yourself. You'll likely need his signature in any case, to get your inspections approved, and he can answer all your questions in terms of local code.

Question 1: is this OK? And does the size of the ground conductor matter? Should it also be 6AWG, or can it be smaller?
That's one for the local electrician to answer! Where I live, the ground conductor has to be the same gauge as the live and neutral, but I've seen smaller gauge permitted in some places.

the hot, neutral, and isolated ground conductors will be run inside the conduit together, and will all be home runs back to the sub panel.
:thu: That's the way I would do it.

As for the isolated grounds, I understand each isolated ground conductor needs to be sent to a separate ground bus bar that is not connected to the ground bus or neutral bus in the sub panel. They also need to be connected back to the ground bus at the main service entrance.
Once again, local rules vary. Where I live, that setup wouldn't pass. Here, all grounds are tied together at the main grounding point, where they are also tied to the neutral. But where you live, that could different.

Question 3: Am I correct that I do NOT need another ground rod outside the garage/studio? As long as the isolated grounds are bonded to the main service ground/neutral bar (which is bonded to the grounding rod at the service entrance), i'm good?
Where I live, that would be fine and correct! .... but where you live... :) Your local electrician can tell you what is the accepted. approved way of doing things.

Stuart mentioned putting a filter on the air intake (From outside to inside), and the return air register to keep the ducts and silencers as clean as possible. Sure having to clean these every once in a while is a chore, but I'd much rather that than the alternative. I've been researching filters, and can't seem to find something that would work. Is there a specific type of filter I should be looking for?
Contact a local HVAC supply store, and see what they have. You can sometimes buy filters in places like Home Depot too. Often sold as "furnace filters", rather than "HVAC filters". They usually come as cartridges with cardboard or plastic frames, and you just slide them into the slot in your furnace or ductwork. In a pinch, I have been known to just buy some kitchen extractor hood filter material, and use that... but once again, make sure it will pass local code! You do want to be careful that the inspector will be happy, and sign his scribbles and stamps on your paperwork, without complaining or telling you to re-do stuff!

One caution here: don't forget to take all the filters into account when you do your static pressure calculations.... You don't want to end up with static pressure that is too high for your AHU to handle.

I also met an electrician in the home depot parking lot yesterday. He seemed like a good guy and I'm going to call him to set up a time for him to come check out the space and see what he thinks.
Smart move! But do check that he is certified/licensed/approved locally!

Question: my garage is a single story gable roof style structure. Do I need a firestop at the tops of the walls between my interior and exterior leafs?
I'd suggest taking a look on your local municipality web site, and see if you can find a copy of the locally applicable building code, then check that to make sure EVERYTHING you are doing complies. You could also ask your inspector in advance! They really are not cruel ogres that are out to get you! Most of them would be happy to tell you what they will and will not pass, just from a phone call or visit to their office, so you have all your ducks in a row before he even comes out to your place for the final inspection. It's worth calling him up and ask his advice. Worst case: he tells you to take a hike! But more likely he'll be happy to know that you are interested in his opinion, and will probably give you good advice.

In the gap between the exterior and interior leafs, I plan on filling that gap with insulation. Should i put something on the concrete floor so that the insulation is not touching the concrete? Could moisture from the concrete saturate the insulation?
There should not be any moisture in the concrete! Hopefully it has cured to the point where it does not sweat any more, and hopefully it is fully sealed from below, and the walls are built properly too, with water barriers and vapor barriers in the correct locations, too. So there should not be any moisture in that cavity.

Also, if you are worried about water somehow getting onto your slab, then you DEFINITELY need to use pressure-treated lumber for your sole plates, not ordinary wood sole plates. Water and untreated wood do not get along very well! Rot, mold, fungus, and other nasty things will be the result... and it will all be hidden inside the wall, where you can't see it, until it is too late... There's also the risk of warping, twisting, bending and other structural things happening, with untreated lumber in contact with water. Bad idea!

But if you are mainly concerned about the insulation, then do NOT use fluffy fiberglass in there: use mineral wool instead. Mineral wool stands up to water a lot better than fiberglass. If fiberglass gets wet, it will dry out eventually, but first it ends up as a soggy crumpled mess, and that won't change after it dries out. Mineral wool batts keep their shape, and return to normal after they dry out.

Should there be a gap without insulation down where the sill plates are? Or should the insulation in the gap go all the way down to the concrete (in between the sill plates), but not touching the concrete?
For maximum isolation, the entire cavity inside the wall should be completely filled with insulation: no air gaps at all. Just insulation.

- Stuart -



Jag94
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Studio Build: Garage Conversion in Los Angeles

#62

Postby Jag94 » Wed, 2020-Oct-28, 13:47

Soundman2020 wrote:Source of the postThat's not such a good idea. That opens you up to ground loops, as you have two different ground points at possible different potentials. Generally, you only want one single ground for the entire building. Are there any signs of corrosion at the point where the second ground conductor is attached to the water pipes? If so, I'd be wary...


Hey Stuart,

Welcome back. I feel like we haven't seen you around in a few weeks.

The garage is detached, so it's a separate building from the rest of the house. The house has 2 grounding rods. And no, there is no corrosion at the point where the 2nd ground conductor is. When we had a brand new 200amp main service panel installed a year ago, the inspector wanted two grounding rods for the whole house. I guess that's code around here. But again, the garage is detached, and as of right now, does not have it's own grounding rod. So I guess I need to figure out if the garage should get it's own rod. Right now, the sub panel in the garage has a ground wire that feeds back to the main panel (through underground conduit), and bonds to the ground bus in the main panel. I'm trying to figure out if that is kosher, or if I need a separate ground bus at the garage, and also how the isolated grounds would play into this.

As for the isolated grounds, I understand each isolated ground conductor needs to be sent to a separate ground bus bar that is not connected to the ground bus or neutral bus in the sub panel. They also need to be connected back to the ground bus at the main service entrance.


Once again, local rules vary. Where I live, that setup wouldn't pass. Here, all grounds are tied together at the main grounding point, where they are also tied to the neutral. But where you live, that could different.


I understand that the grounds need to tie together at the main grounding point (where it is bonded to the neutral) in the main service panel. However, everything that I've read, shows that if you're using a sub panel for the studio, then the safety grounds and neutrals are kept separate in the sub panel, the isolated grounds are bonded on a completely separate ground bus that is not tied to the sub panel, and all of those (safety ground, neutral, isolated grounds) are then tied together at the main service panel.

I am having a hard time finding an electrician around here who knows star grounding/isolated ground systems.

Contact a local HVAC supply store, and see what they have. You can sometimes buy filters in places like Home Depot too. Often sold as "furnace filters", rather than "HVAC filters".


I found some lightweight filters at home depot that I can cut to size. They are very thin, so I'll probably change them out every month until i run out of the pack I bought. I have since found some filters that will do a better job, and can be cut to fit my irregular shape air intake vents. I'll post some pictures when I do a build update.

There should not be any moisture in the concrete! Hopefully it has cured to the point where it does not sweat any more, and hopefully it is fully sealed from below, and the walls are built properly too, with water barriers and vapor barriers in the correct locations, too. So there should not be any moisture in that cavity.


The concrete is old, built with the house in the 30's. So it's definitely cured. But I don't know how they poured concrete back then, or whether or not they sealed it from below.

Also, if you are worried about water somehow getting onto your slab, then you DEFINITELY need to use pressure-treated lumber for your sole plates, not ordinary wood sole plates.


I used pressure treated for my sole plates, plus added a sill sealer under them, and caulked the perimeter.



Jag94
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Studio Build: Garage Conversion in Los Angeles

#63

Postby Jag94 » Tue, 2020-Nov-17, 03:01

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.

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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.

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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.

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I found these filters that I put in the intake hood for now. They were super cheap ($5 for a pack of 12). I have to use 2 per hood, so $5 will last me 6 months if I change them every month, which is totally reasonable to me. I'll continue to look for a better option, but for now, this will work.

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Attachments
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Jag94
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Studio Build: Garage Conversion in Los Angeles

#64

Postby Jag94 » Tue, 2020-Nov-17, 03:14

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.

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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.

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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.

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I built small gussets out of scrap plywood, and used them to hold the rafters together. My Structural Engineer didn't care for the gussets, and wanted me to secure them with a 2x4 collar ties, so I did that as well. I figured it couldn't hurt to add stability to it. The gussets actually made it easier to align them and secure the collar ties.

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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.

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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.

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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.



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Starlight
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Studio Build: Garage Conversion in Los Angeles

#65

Postby Starlight » Tue, 2020-Nov-17, 05:03

Jag94 wrote:Source of the postThis build is taking a lot longer than I anticipated, and I'm severely over budget.
I think many of us have the same story to tell.
Jag94 wrote:Source of the postRod was very adamant that all of my flex duct runs were very short, and he approved of this design.
Yes, that is exactly what I did so, of course, I agree.
Jag94 wrote:Source of the postI 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.
Brilliant!
Jag94 wrote:Source of the postI hired an HVAC company to run and connect the refrigerant lines ... it cost me WAY more than I was anticipating.
Stuart explained the process to me and about how expensive the refrigerant fluid or gas is. That will account for at least some of the cost, plus the cost of the twin insulated copper pipes.
Jag94 wrote:Source of the postI wish I knew enough about this to do it myself.
I understand, at times having the same thought. I expected to do far more of my studio build myself but I have come far enough that I can see the benefit of having professionals do what they can do in their sleep better than I can when I am doing my best. Sure, it pushes costs over budget and takes time waiting for professionals to be free but in the long run we each have to choose the best balance of time, cost, expertise and legal requirements.

We have had a second wave of coronavirus and are half way through a 90-day complete lockdown, so you are now overtaking me with your build. It is good to see it coming along so well. Congratulations!



Jag94
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Studio Build: Garage Conversion in Los Angeles

#66

Postby Jag94 » Tue, 2020-Nov-17, 16:53

Starlight wrote:Source of the post Stuart explained the process to me and about how expensive the refrigerant fluid or gas is. That will account for at least some of the cost, plus the cost of the twin insulated copper pipes.


I was fine with having them come by to connect the refrigerant lines. But I should have cut the hole in the outer leaf myself, and ran the lines before they got there. They used up a lot of time (I was paying them hourly) to do tasks that I could have done. Then they connected the electrical which took them over an hour, that I could have done myself. I realistically only needed them for about an hour, and they ended up being there 3.5 hours, and the hourly rate isn't cheap. So I could have saved money there. But you are correct, and since they did do the work, I know it was done correctly, even if I could have done SOME of it myself. They have to come back when it's time to install the indoor unit, and again, I'll do as much prep as I can so their time here is short.


We have had a second wave of coronavirus and are half way through a 90-day complete lockdown, so you are now overtaking me with your build. It is good to see it coming along so well. Congratulations!


Oh bummer! 90 day complete lockdown? That's intense. We are seeing massive surges here in LA too, but I think the city/state is too worried about economic implications of another lockdown, so they're urging people to stay home if possible, and to wear masks everywhere. But it doesn't seem to be helping. Hopefully you and your family are staying safe.

I didn't want to over-take your build. You had so much useful information for when I got to each respective step. Now I have to look somewhere else! haha. I need to finish this thing up. We have a baby on the way and my wife is starting to get on my case about not having this thing finished. So... back to it!



Jag94
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Studio Build: Garage Conversion in Los Angeles

#67

Postby Jag94 » Fri, 2020-Nov-20, 20:13

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.

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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).

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