Sealing gaps in exterior structure with caulk or ?

I'm chomping at the bit to get started constructing my studio but i'm still in the planning stages. So, to give me something to do, i've decided to start sealing up the outer shell. I'm planning a roughly 11x17x18 room within a room for a single room control room/production studio but I figure regardless of what I build inside, this will need to get done first. It is a 24x24' detached garage, built on a slab on grade with exposed 2x4 studs, 16" on center and OSB sheathing and some sort of panel siding on the outside. the roof is a 3/12 slope which is 12' in the middle and 8' on the sides. It's like civ. Some rather poorly cut openings where the rafters meet the plate and exit the building to become the eaves. I can see daylight through a bunch of those. And there are various places where some plumbing for the fire sprinklers and conduit and boxes for electrical has been roughed though to the exterior wall and it has not been sealed. I bought some putty pads and backer rod and a tube of GG Acoustic caulk just to get started. (I found out about the OSI caulk after the fact which seems like th better deal?) I don't know if the GG caulk can be used for anything other than drywall corners. It doesn't say anything about that on the website and on the tube it says it's for the drywall seams or edges. Can it be used for small gaps in the OSB and stud, or conduit or pipe and OSB, or exterior siding and stud? Everything I've read in the resource section here seems to be referring to caulking drywall edges. is there something else I use for this? What about the larger gaps. there are a few places where the workmanship is letting me down. some gaps larger than 5/8" i think. What can I do for those? caulk probably is no good? and expanding foam i read here is a no-no. After I tackle this stuff I'll move on to the sectional garage door, 4x3' window, a fairly well sealed but hollow core door, and two roof vents which i'm sure i'll have to keep functional somehow. It seems a little silly to worry about small holes in the rest of the building when the re is a 16x7 sectional door on one wall but something tells me i have to try.

I can see daylight through a bunch of those.

:ahh:

And there are various places where some plumbing for the fire sprinklers and conduit and boxes for electrical has been roughed though to the exterior wall and it has not been sealed.

:shock: :roll: OK, the basic goal you should be looking for is not just to get an air-tight seal, but rather to get an air-tight seal that also retains the surface density all around the building shell. In other words, hypothetically, if you have a 5/8" OSB on the outside, and there's a gap where two of those meet, then not only do you need to seal that gap, you need to do it in such a way as to ensure that the surface density where the gap is will be roughly the same as the surface density of the OSB, which is about 9kg/m2 (roughly 1.8 psf). Caulk is a bit more than twice as dense as OSB, so you'd need to ensure that your caulk penetrates at least half way thorough the gap, to be certain you have the right surface density. So if your caulk only goes in 1/8" that's o good. 1/4" would be borderline. 3/8" would be ideal. Now if you can caulk from both sides and get 100% fill, that's fantastic. Or better still, push some backer rod into the gap, half way deep, and caulk from both sides, to get a triple seal. But if the gap is more like a crack, too small to get backer rod into, then you need to pay special attention to detail, to ensure that you force the caulk in deep enough to get at least half way through. OK, that's for gaps and cracks. For big holes, it's better to cut a piece of wood to the right shape, smother the face with caulk, then nail/screw it in place, and caulk again later.

I bought some putty pads and backer rod and a tube of GG Acoustic caulk

.... One tube? Or one box of tubes? Or one crate of boxes of tubes? Better to get a truckload of crates of boxes of tubes... :) In other words, you are going to need STACKS of caulk. More than you could even imagine.... So get the least expensive stuff that does the job! And GG caulk is not it. Much as I love their GG compound, their caulk is not so good. It cracks as it dries, if you make it too thick, so you need to go over it again, carefully. Better to go with something else. You can get pretty good results from plain old bathroom or kitchen caulk, actually. As long as it is good quality, sticks like crazy, and does not harden even when fully cured, you'll be fine. In other words, the type that stays soft and rubbery, even when fully dry.

is there something else I use for this?

Use it for everything! Air-tight seals are critical for good isolation. Inspect every square inch of your existing shell as though your life depended on it, and seal every crack, gap, hole, and protrusion. If you aren't sure that what you are seeing is a crack, then seal it anyway, just in case: And even if you are totally certain that it isn't a crack, then STILL seal it! You never know... :) Did I mention that sealing is important?

After I tackle this stuff I'll move on to the sectional garage door,

What are your plans for that? Take out hte door completely and brick up the gap? Or just lock it in place and build an isolation wall in front of it?

4x3' window,

Ditto: Plans for that? Do you want to keep the window, or do you plan to get rid of it? If you plan to keep it, then you will very likely need to replace the glass at least, to get good isolation, and maybe also the frame.

a fairly well sealed but hollow core door,

That has to go. No question. Hollow core doors have no place in studio. Poor isolation, and filled with a resonant cavity 6 feet high and three feet wide? :shock: Not much use.

and two roof vents which i'm sure i'll have to keep functional somehow

Tell us more about those vents. If you are talking about a typical garage roof, with a ridge vent along the top and inlet vents under the eaves, then you cannot use your roof as the outer leaf. In order to be useful for isolation, each leaf has to be sealed airtight. You cannot seal a roof airtight, as it needs to be ventilated. Conclusion: you cannot use a vented roof as the outer leaf. You will need to build a three-leaf ceiling, which is not as bad as it sounds. Just extra cost, and extra time.... (OK, so it is bad... )

It seems a little silly to worry about small holes in the rest of the building when the re is a 16x7 sectional door on one wall but something tells me i have to try.

That's why we need to know about your plans for sealing off the door! That's rather important! Did I mention that sealing your room air-tight is critically important? - Stuart -

Stuart, again, thank you! I didn't realize that I could use regular bathroom caulk for sealing the cracks/leaks in the shell. Are you talking about the silicone stuff or the "siliconized" stuff or does it matter? I thought it needed to be Acoustical caulk. I did realize that i would need boxes of the stuff, i just wanted to try out the GG caulk before i made some larger purchases. the OSI SC-17 seems like a great price though. it's just not readily available at the big box store like kitchen caulk. So, i'll definitely be pushing plenty of caulk and if possible backer rod into those gaps and sealing from both sides. no outright holes to speak of. thanks. on to the roof vents. there are no ridge vents or vents on the eaves. just two of these round things on the west side of the roof near the top. i didn't think it would be a good idea to seal them up completely so i was going to make baffle boxes for them. is that ok? one of them will be over the proposed control room and the other is situated over the workshop space. For the window, I wanted to keep it, not for daylight to the control room, but for natural light in the workshop space. the problem is, the way the proposed control room would be laid out, the 11' wall would end right in the middle of this window. I was planning on only sealing half of it up with drywall, so that the outer leaf of the control room could attach and seal to it. but the other half of the window would be uncovered. As i type this i'm picturing you laughing at me. I realize that this is less than optimal but i also thought that since I was planning to use this design for the build (that you graciously shared with me the other day) that i was effectively changing the outer shell to the outside of this new outer wall and that what is on the other side of that, such as this window, the garage door, and the hollow core door, would be less acoustically significant. You mentioned a three leaf system when talking about the roof vents. is this what you were talking about, except for the walls? This markup that I did on your image just shows the orientation of everything, it's obviously not to scale. And i don't know what the inside-out construction means. I was just thinking of doing this but the conventional way with the drywall placed on the inside of the control room. For the hollow core exterior door, i could replace it with a solid core door. I don't see a problem with that. again i thought it wouldn't matter as much because of the room within a room (within a room) but if matters that much the expense is not prohibitive. For the sectional door, that is a bit trickier. the city code requires that the door be functional. My wife would like the door to be functional. I think it would be a good idea to keep it functional. I realize that this means that I won't be able to get a good seal on it but i have t do my best. that is why i was wondering if it is silly doing all of this other caulking if i can't fully seal off the garage door. Again I was hoping that this room within a room (within a room) design would work in my favor here. Just for additional reference, this is my original post which was the first one about this project, (which i think i probably put in the wrong sub-forum). http://www.johnlsayers.com/phpBB2/viewtopic.php?f=1&t=20963&p=141688#p141688 I have edited it a couple of times since receiving some specific feedback from you on another post that I made about the dimensions of the room. But it contains some info about my structure and planned use and some photos.

2k4s wrote:

Stuart, again, thank you! I didn't realize that I could use regular bathroom caulk for sealing the cracks/leaks in the shell. Are you talking about the silicone stuff or the "siliconized" stuff or does it matter? I thought it needed to be Acoustical caulk. I did realize that i would need boxes of the stuff, i just wanted to try out the GG caulk before i made some larger purchases. the OSI SC-17 seems like a great price though. it's just not readily available at the big box store like kitchen caulk. .

I've used regular DAP Alex Plus for the last few studio builds. Definitely cheaper than the GG caulk and it's available at all hardware stores. http://www.dap.com/dap-products-ph/alex ... -silicone/ It's acrylic but with added silicone, which helps with the flexibility.

Did you use it on the drywall seams and for sealing up the shell?

2k4s wrote:

Did you use it on the drywall seams and for sealing up the shell?

Yes, everywhere. I'm always on very very very limited budgets or helping out someone on a similar budget as well as always doing builds in rental spaces where you never know how long you're going to get in a location. I wish I could afford the expensive stuff and now that I'm faced with building ANOTHER studio, but this time on property I actually own, I'm sure I'll be using it again. I did build a pretty solid iso booth in my last control room-less studio and had the budget to spend on nice things like caulk specifically for sound (i'm not sure what it was called, but I bought it from the same place that sold me the green glue, maybe it's the stuff that is made by green glue company?) It seemed a bit more flexible. The OSI SC-175 is damn affordable though... If you buy by the case, $6.48 for a 28oz tube (.23 per oz) while the alex plus is $1.42 for a 10 oz tube (.15 per oz) I'll have to look around here to see what other people say. Home Depot will ship it to your local home depot location.

that's great info! through the link in the caulk reference pages in this forum, I found it here for the same price for individual tubes but they charge like $10 for shipping unless you buy over $199 of other stuff. http://www.toolup.com/OSI-Sealants-SC17 ... nd-Sealant home depot, like you said, is $77.76 for a 12 pack with free shipping. http://www.homedepot.com/p/OSI-SC-175-2 ... OSI+SC-175 but i don't think I can wait a week to get started on sealing the shell. I'll get the bathroom caulk in the meantime whilst I wait for the shipment of OSI and use that on the drywall.

There's so much caulking to be done... I suffered a compound fracture on one arm almost a year ago, and then a bad sprain on the opposite hand 6 months ago!!! Both injuries have slowed me down when it comes to labor. Spent the weekend moving 5 yards of garden soil and in so much pain now... Just thinking about all the caulking I'll need to start on soon to seal up the outer shell makes my hand hurt. I need to look into an upgrade in the caulk gun department.

I need to look into an upgrade in the caulk gun department.

One word: "Pneumatic". Splurge a bit, and get yourself a compressor and a pneumatic caulking gun that takes standard tubes. You will be soooooooo glad you did. That speeds things up a lot, and makes it much, much easier. The compressor also has many other uses: get yourself a framing nailer as well, and multiply the speed of building walls, ceilings, and suchlike. And also a finish nailer / stapler to accelerate your fabric attachment, and all the small trim and finish stuff that you need to put in. ... Yeah, the compressor ain't cheap, but it is very much worthwhile. If you want your build to go faster, simpler, and less painfully, get one. - Stuart -

Soundman2020 wrote:

I need to look into an upgrade in the caulk gun department.

One word: "Pneumatic". Splurge a bit, and get yourself a compressor and a pneumatic caulking gun that takes standard tubes. You will be soooooooo glad you did. That speeds things up a lot, and makes it much, much easier. The compressor also has many other uses: get yourself a framing nailer as well, and multiply the speed of building walls, ceilings, and suchlike. And also a finish nailer / stapler to accelerate your fabric attachment, and all the small trim and finish stuff that you need to put in. ... Yeah, the compressor ain't cheap, but it is very much worthwhile. If you want your build to go faster, simpler, and less painfully, get one. - Stuart -

SOLD. I was going to borrow a friend's compressor, frame nailer and finish nailer... Now that I know there's a caulk gun that can operate from that, it just makes sense for me to get my own stuff instead of borrowing his on and off over the next year. Thanks Stuart.

I was thinking about getting a Ryobi cordless caulking gun (because those are the batteries I already have). but i do have a compressor. i didn't know they made pneumatic ones. I'll have to look into that instead because I'm sure the battery will die mid-squeeze whilst i'm up a ladder.

I just bought the Ryobi caulk gun. It was sort of an impulse buy because I was in the big orange store and it was on sale for $40 USD. I'll let you folks know how it performs once I start using it. Also bought a case of the Alex Plus caulk for $24. Will report back on that too. All they sell at that store is 3/4" backer rod. I bought some but i don't know if it will be small enough for my shell crack sealing needs. we'll see.

2k4s wrote:

I just bought the Ryobi caulk gun. It was sort of an impulse buy because I was in the big orange store and it was on sale for $40 USD. I'll let you folks know how it performs once I start using it. Also bought a case of the Alex Plus caulk for $24. Will report back on that too. All they sell at that store is 3/4" backer rod. I bought some but i don't know if it will be small enough for my shell crack sealing needs. we'll see.

Cool!

So, the Ryobi caulk gun is a joke. It is difficult to control the bead and it sometimes busts through the back of the tube which creates a huge mess and a waste of caulk. returned it to big orange store after one day. back to cramping forearms. need to eat my spinach.

Here's what you need: If I have time tomorrow, I'll try to remember to take a photo of my rig and post it here. I have a pressure gauge and pressure valve on the end of mine. Makes it much easier than running back to the compressor each time I need a minor tweak in the bead (= pressure). - Stuart -

the pressure valve is a great idea that i wouldn't have thought of it's quite time consuming. after a couple of hours i've only done a small corner of the inside of the garage. working my way along the top right now. i'm also quite sloppy with the caulk. I need to get my act together before I start caulking the outside or it's going to look like dog's dinner. do i need to caulk all of the interior vertical studs too (the ones that the OSB siding is nailed onto)? and how about the seams in the roof sheathing where they butt up against one another? it seems like those would be already covered by the paper and shingles?

the pressure valve is a great idea that i wouldn't have thought of

Aren't you glad you paid all that money, to have such great advice from us? :) OK, I managed to get a shot of my setup, for what it's worth: You can see the valve knob sticking out just next to the gauge. This has turned out to be great, as you can get very fine tuning of the bead by adjusting the pressure, and it's easy to make sure you get the same bead the next time, by just noting down what pressure you used! Different caulks and different applications need different pressures. It's a great time saver, and helps to get the job done much neater, and faster., and with less waste.

it's quite time consuming.

Yup! Welcome to the world of studio construction! :) Things will ALWAYS take much longer, cost much more, and be far more complicated than you ever imagined, even in your wildest, most terrifying nightmares... :)

i'm also quite sloppy with the caulk.

It takes a while to get the hang of it, if you are just doing it for the first time. There are some useful tolls that you can by to help clean up the caulk bead, if you really want to, put a finger dipped in water does a pretty darn good job too, and is much cheaper! (As long as you don't mind digging caulk out of your fingernails for a while, after you finish....)

do i need to caulk all of the interior vertical studs too (the ones that the OSB siding is nailed onto)?

Here's my philosophy about caulking: if there is an obvious hole, gap or crack, then caulk the hell out of it, with high pressure to force the caulk deep. If it just looks like ot might be a crack, or gap, but you aren't sure, then caulk it anyway. And if you look at it carefully, and you are absolutely certain that there is no gap, hole or crack, then caulk that too, because you never know....

and how about the seams in the roof sheathing where they butt up against one another? it seems like those would be already covered by the paper and shingles?

Whooaaaa!!! What exactly are you calking up there? Is your roof deck supposed to be ventilated? If so, then it cannot be your outer leaf.... - Stuart -

I've been using the finger in water method so far but lots of waste and a bit sloppy. I'll definitely be cleaning up more when i caulk the outside. the ceiling has plywood with silver radiant heat barrier or whatever it's called. yes it is supposed to be ventilated i'm sure but i thought that was what the roof vents are for (which i intend to make baffles for.) where those sheets of reflective coated plywood on the ceiling butt up against each other, I was wondering if I need to caulk those gaps too. there is roof paper and asphalt shingles on the roof? nice visual on the gun and valve. now i know exactly what I need. thanks I'll take some photos of what I've done so far. just some electrical and caulking at this point. it's slow going doing everything for the first time.