Silicone sealer or spray foam? Reflectix or Panda Film?

[SBudz08]

Hello all,

I started building an enclosed grow room in my garage about a month ago. I'm almost done mounting all the exterior plywood to the framing and I'm wondering how I'm going to seal the gaps between plywood sheets. I've read about silicon caulking and it seemed the way to go but then I saw some videos on spray-on foam insulation and I'm not sure which would be best.

I have a mix of used fluffy yellow insulation I bought cheap off an ex-grower from Craigslist and some hard foam insulation a friend had left over from a soundproofing project. Would any of these be a fire concern?

Finally, I'm not sure what I want to put over my insulation - Reflectix or Panda Film. I'm leaning toward Reflectix from what I've read so far but I'm having trouble figuring out if single or double reflective Reflectix is right for my project.

I'll be running 2 1000 watt XXXL Magnums.

Thanks for reading and for any constructive criticism / suggestions!

 

[Hold Your Fire]

I'd have put the plywood on the interior and used flat white paint. It's nice to have a real wall inside, instead of something floppy.

Not too late to use it still.

 

[Waterlab420]

Roxil insulation, and panda film.

All personal preference though, depends on who ya ask.

 

[Midwest sticky]

im with holdyourfire on this one its
cheap easy durable works well but if you dont feel like putting up a wall and painting it then go with the panda film

 

[Jhhnn]

I'd have put the plywood on the interior and used flat white paint. It's nice to have a real wall inside, instead of something floppy.

Not too late to use it still.

Yep. Insulation first between exterior studs, then vapor barrier, then plywood or sheetrock on the inside. I like sheetrock because it's fire resistant & because it's easy to fiberglas tape & mud the joints & corners. Kilz primer & Benjamin Moore flat white paint. There are lousy pics of my new space in my albums.

Cheap paint sux.

 

[Granger2]

I've use silicone caulk a lot. It only offgases for a few days, mostly the 1st 24 hours, and just ammonia and methyl alcohol. I've never smelled either during cure, even after applying a lot of it.

I like white paint also. Im not sure about spray foam, but I've heard and read that some of them outgas some stuff your plants won't like. Nor you. Good luck. -granger

 

[Mad Lab]

Yep. Insulation first between exterior studs, then vapor barrier, then plywood or sheetrock on the inside. I like sheetrock because it's fire resistant & because it's easy to fiberglas tape & mud the joints & corners. Kilz primer & Benjamin Moore flat white paint. There are lousy pics of my new space in my albums.

Cheap paint sux.

Second that. Sheetrock.If you have negative/positive pressure off your panda tent will suck in or expand, hard to build tight.

Cheap paint sucks, good paint is ok.

I prefer super reflective mylar, its the only thing I really notice a difference on the outsides of my canopy footprint, a huge effect on my overall yield.

Most will disagree stating white is as reflective. And those who admit mylar is 5-8% more reflective (91/98 I think) say that it creates hotspots. I find this to be untrue if you have proper ventilation and your room not too hot to begin with, and i run DE gavitas.

 

[SBudz08]

Thanks for your feedback everyone! Gonna go with the silicone sealer. I found an ad for some surplus Gold Bond 5/8 fire resistant drywall not far from me. Gonna put that up and shoot it with some flat white paint that isn't cheap

 

[Jhhnn]

Thanks for your feedback everyone! Gonna go with the silicone sealer. I found an ad for some surplus Gold Bond 5/8 fire resistant drywall not far from me. Gonna put that up and shoot it with some flat white paint that isn't cheap

5/8 is good stuff- nice find. Tape & mud will cover your sins much better than silicone seal. It's not hard once you get the hang of it. A grow space would be good practice because it doesn't need to be a great job. Don't forget the primer unless you're using some of the new self priming stuff.

 

[SBudz08]

Hey Jhhnn, isn't a good idea to still caulk the outside plywood to make sure I don't get insects creeping in? I'd rather be safe than sorry, plus I'm having a blast doing this project! Can I use the drywall mud to patch up my plywood?

 

[queequeg152]

if you are not cladding the exterior OSB sheathing in foam board, you should tape it tight, and then wrap and cap nail a tyvek or similar material.

you should spray foam gaps and aggressively air seal prior to laying in batts. id suggest buying a dow foam gun... this is the one i own.

http://www.bestmaterials.com/detail...inblliKV0pWfFOZpMj0xSVUlbIRF1uoiF-BoCuyPw_wcB

you will need like 1 can of enerfoam for a small project like this... and a can of cleaning solution for when you are storing the gun.

ive put like 6 cans through my cheap shit gun, and it continues to work fine, provided i keep it cleaned and dont store it with the foam can for excessive periods of time.

i would not use plywood indoors as it costs a criminal amount, and its a fire hazard. mylar is also a fire hazard.

for the love of god, read about how to properly lay bats BEFORE you lay batts.

like 80% of fiberglass batts that are layed in residential construction are criminally poor quality, dont be another hack builder.
take some pride in what you build.

 

[Jhhnn]

Hey Jhhnn, isn't a good idea to still caulk the outside plywood to make sure I don't get insects creeping in? I'd rather be safe than sorry, plus I'm having a blast doing this project! Can I use the drywall mud to patch up my plywood?

Caulk won't hurt. I like the acrylic latex stuff. I never tried drywall mud on plywood.

 

[queequeg152]

the only thing that you should be caulking is sill plates. lay a fat bead, like 1/4 across. you should empty one of those small 10oz tubes like every 50 ft.

foam everything else... outlet boxes, door frames, top plate penetrations, duct boots ... i cant think of anything else.

caulk is not great at air sealing, its better at preventing water from penetrating places it should not.

to seal OSB, like i said. you need to tape the seems.... cheaper than caulk
products are called seam sealing tape or seam sheathing tape...

oh yea, some of those tapes require primers before you lay down the tape. make sure to read the manufacturers instruction. if you do it correctly, the tape will last far longer than any caulked seem.

 

[queequeg152]

i mean.. caulk IS good at air sealing... better than foam really. its just too difficult to apply into large gaps, as you need to push in backer rods and shit. its also expensive as fuck.

I use DAP dynaflex on very difficult to reach air leaks such as in the eves of the attic, where a foam gun will not reach. Its a pita, but the only way.

a 12 dollar can of enerfoam will lay hundreds of feet of caulk like 1/4" beads of foam. the stuff expands reletivly little, and cures to a very sticky flexible foam. you can use it as a foam adhesive as well.

 

[LowlyWorm]

I used the purple mold resistant drywall and mudded and taped it all up. I was on the fence between it and osb but I figured for a similar cost the rock made the most sense. DAP makes a low VOC sealant that can fill up to 1/2" at a time, thats what I used for the door gaps and other larger spots. Make sure to seal up your outlets as well (foam cut in the shape of the face plate works great). For paint I used the Behr Ultra Pure White all in one (flat). Its bright as all hell and tight as a ducks ass. You'll be stoked on your design.

 

[SBudz08]

Thanks everyone for your feedback! Here's my Lowe's shopping list so far. Keep the suggestions coming! I'm by no means a know it all or a pro at this kind of thing, but it's been pretty fun so far.

1) Roxul R15 insulation since my framing is all 2x4.
2) Looked further into the listing for cheap leftover Gold Bond fire resistant 5x8 and compared that with the purple, which is a little more expensive because it's also moisture and mold resistant. Purple seems worth the extra investment.
3) Blue Hawk Underlayment Seam Tape for exterior plywood seals
4) DAP silicone caulk. For sole plates inside and out?
5) DOW Gaps & Cracks foam sealant, gun & cleaning solution. This is probably the OCD freak in me talking, but I feel the need to use this shit between every stud and joist!
6) Probably gonna just get my handyman friend to come in to spray primer and paint the interior. He did a great job mounting my framing into the concrete.

Also another question - when I'm cutting holes out for ducting / fans, what do people usually do? Do they insert some sort of short duct tube and then run the ducting through that or just run the ducting on its own? I also built a little wooden stand and mounted my outside intake fan and filter to it. I plan on sliding it right up to the outside of the grow room next to an outdoor vent. Just a hole here or some sort of tube?

I'm a noob when it comes to anything more than a low-budg closet grow. Thanks!

 

[queequeg152]

Thanks everyone for your feedback!
4) DAP silicone caulk. For sole plates inside and out?
5) DOW Gaps & Cracks foam sealant, gun & cleaning solution. This is probably the OCD freak in me talking, but I feel the need to use this shit between every stud and joist!
Also another question - when I'm cutting holes out for ducting / fans, what do people usually do? Do they insert some sort of short duct tube and then run the ducting through that or just run the ducting on its own? I also built a little wooden stand and mounted my outside intake fan and filter to it. I plan on sliding it right up to the outside of the grow room next to an outdoor vent. Just a hole here or some sort of tube?

I'm a noob when it comes to anything more than a low-budg closet grow. Thanks!

a silicone caulk is not ideal in this situation. pure silicone caulks are for glass or ceramic joints mostly... you really want a cheap acryllic or water based SEALANT type caulk.... to the premium sealants of this type they may add like 2% siloxane to aide in flexability.

i think Dynaflex has this 2% if i recall correctly... hence why its always reccomended for retrofit air sealing. i can reccomend it first hand... get the jet black, as the transparent and titanium white SUPPOSEDLY shrink more than the black.

 

[queequeg152]

you will not need gaps and cracks foam imho. unless you are looking to seal rough in holes like from plumbing drops.

for wire penetrations use enerfoam... like i said enerfoam is more sealant and adhesive than it is an actual foam... it will remain flexible and stick to wood and drywall very very well... whereas the window foams and gap foams become more rigid, and tend to pull away from wood and drywall, and especialy from wire hole penetrations... where one might expect the wire to periodically be molested... this molestation can cause the foam to loose adherance to wire sheathing and wood.

under ideal circumstances... wire hold penetrations should be sealed with very specialized mastic tapes... i forget the name, but its far more time intensive than caulking and foaming... it will however hold up to endless abuse and molestation.

 

[queequeg152]

oh and for the love of god... BUY EXTRA FOAM TIPS... my gun came with like 5 foam tips... i went through all 5 in less than a day. problem is... when you start and stop for like an hour or so... when you pull the trigger the tip will just shoot off... as foam has semi solidified in the tiny nozzle tip. you can clean them if you are fastidious, but i am not.

they are necessary to get into like 1/8 - 1/16 gaps... without them you have to cap the gap... which is not ideal, and will result in you wasting more foam than is necessary. these guns can throttle the foam to extreemly low flows... making the filling of very small voids and gaps very easy unlike those straw can abortions.

i got a bag of 100 of these tips

http://www.amazon.com/DOW-Enerfoam-...8&qid=1423863397&sr=8-3&keywords=dow+enerfoam

these are what im talking about, though you can get them on amazon too.

http://www.awarehousefull.com/tapered-nozzle-tips-for-barbed-tip-pro-foam-gun/

 

[SBudz08]

So far so good! Thanks everyone for the help so far.

Started a new thread for the room here: https://www.icmag.com/ic/showthread.php?t=301792