Insulating gaps in detached garage

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RadicalEd

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Hi all--

not sure if a Homebrewing forum is the best spot to ask for insulating advice, but I've been surprised before by the depth of knowledge here. And it's for a good homebrew cause!

I'm trying to make my workshop/homebrew space in my detached garage a bit more comfortable for these cold Michigan winters. There's an 240V electrical heater out there, but it runs 50% of the time just for a 20 degree temp rise. That gets expensive quick! Fortunately, the place is quasi-inslated: 3/4" foam boards on the walls, insulated garage door, and 3/4 foam panels (maybe for acoustical purposes?) on the ceiling. Just one glaring issue--there are gaps in between the joists on 2 walls, in between the 4x6's of the main frame.

So, what's the best way to fill those gaps? I'm thinking of just getting some kraft faced batting, cutting it down to size, and shoving it up in the gaps. This appears to be the only 'air gap' to the outside environment--will this be good enough? Or, am I really looking at a more significant outlay in insulating the ceiling space--which would probably require ripping down the foam ceiling boards and doing something in the inaccessible attic space.

20181128_214046.jpg
 
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It wouldn't be much work to stuff some R30 kraft faced insulation in the openings and then sheetrock around that beam...

Cheers!
 
This. ^

Kraft-faced fiberglass insulation, then staple some 4-mil plastic sheeting over it if you don't want to sheetrock it right away. Don't forget to push some small pieces of fiberglass up into those gaps between the rafters where the wall meets the ceiling. That will take a big chunk out of your heating expenses, even with the ceiling left as-is. If you want, you could put fiberglass batts in the ceiling, which will help even more.
 
Unfortunately I don't think the ceiling panels are sturdy enough to support fiberglass batts above them, it's really just a 3/4" foam board. Looks like sheetrock, but sure isn't!

I never even thought of plastic sheeting. Probably not a bad idea!
 
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caulk the perimeter then put the reflex in then your insulation done
 
Unfortunately I don't think the ceiling panels are sturdy enough to support fiberglass batts above them, it's really just a 3/4" foam board. Looks like sheetrock, but sure isn't! [...]

Begs the question why the builder didn't take the half hour to cut some more foam board and cover up that gap...

Cheers!
 
I heat my shop with wood stove..the picture you posted is of a Post and beam frame...a couple of ways to help . Frame a wall between the post..and install insulation .then water board purple...or you can build a room for brewing..mine is 5x12.. or you can spray foam the walls..ju ju saying that the tighter it gets . you still will have to deal with the moisture.... i over build ... sorry but I get really great money for changing light bulbs...the foil bubbles is going to be the cheapest way to start... Best done on a very windy cold day..
 
Begs the question why the builder didn't take the half hour to cut some more foam board and cover up that gap...

Cheers!

It's weird. The building has a lot of insulated 'features' (like the doors, walls, etc) but the ceiling appears to be just acoustical insulation to cut down on shop noise. Looks a lot like this:

https://www.homedepot.com/p/1-2-in-...ic-Insulation-Sound-Board-BSNAT85US/207168829

Not sure if it has any real thermal properties. So it looks like they gave up on insulating the ceiling, despite that being the most important factor for insulation. The construction of this building is a bit whack.
 
Hey 4of7--How good is that reflectix working for you? I sure like the idea of unroll and glue! But I've heard that reflective type insulation isn't always ideal for building insulation.
 
Reflectix will help a little, but its R-value is about 1. That foamboard you referenced is probably R2 or maybe R2.5.

There are two ways a building will lost the most heat. One is air infiltration; a home can lose up to 1/2 its heat just on air infiltration. So checking for and sealing gaps will help you, possibly quite a lot.

The second is conductive heat loss, which is what insulation helps with.

On the wall, you can add fiberglass insulation (using furring strips to fur it out if necessary), or you could add 2" foamboard (about R10) as long as you isolate it with drywall.

But the warmest air is near the ceiling, so the most impact will be felt there. If you wanted you could put drywall up on the ceiling, and then blow some cellulose insulation up there above it.

My garage is attached to the house, but no heat in it. The walls are insulated with 3.5" of fiberglass, and there's about 6" of blown-in insulation above. I live in Wisconsin, and that garage virtually never gets below 32 degrees. The cars give up enough heat to keep it above freezing.

But my garage is both very well sealed and reasonably well insulated. That's your target, i.e., both sealing it as well as insulating it.
 
Totally agree on air sealing. The garage door seals probably need replacing, but otherwise the place looks pretty well air sealed....ignoring the huge gaps in those header boards :eek:.

I admit I'm nervous about putting up drywall on the ceiling. Never mind the physical challenge of getting that stuff up to a 10 ft ceiling, that acoustical foam was put there for a reason. Wouldn't drywall turn the place into an echo chamber? I'm thinking a work-around solution might be to use mineral wool insulation, which theoretically should hold itself in place above the foam board. But then again my goal is to do this on the cheaper side...because if budget is unlimited I would just have someone come in and spray foam the heck out of the place! :p
 
Hey 4of7--How good is that reflectix working for you? I sure like the idea of unroll and glue! But I've heard that reflective type insulation isn't always ideal for building insulation.
Your building is post and beam..Which means there are 4x6 post that are tied by beams..it does not look whack...however you should see alot of carrage bolts used where they are tied together...it should look the post that are used outside wood decks..the part that carries the joist and decking...which your pic kindof shows...nothing wrong..normal for that type of construction method...But you now are trying to build your brew house?.I use the cheap chaulk as a glue then cut the reflect push it on the glue done...the chaulk will seal the drafts and the reflex will be the fisrt step in the insulation.I will use what ever thickness i can get..
 
20181209_164548.jpg 20181209_164559.jpg this is on the northside in the basement brew room...
 
Totally agree on air sealing. The garage door seals probably need replacing, but otherwise the place looks pretty well air sealed....ignoring the huge gaps in those header boards :eek:.

I admit I'm nervous about putting up drywall on the ceiling. Never mind the physical challenge of getting that stuff up to a 10 ft ceiling, that acoustical foam was put there for a reason. Wouldn't drywall turn the place into an echo chamber? I'm thinking a work-around solution might be to use mineral wool insulation, which theoretically should hold itself in place above the foam board. But then again my goal is to do this on the cheaper side...because if budget is unlimited I would just have someone come in and spray foam the heck out of the place! :p
I would suggest to use ridge foam board on the ceiling 2 in..it is easy to handle by you self. Do no just nail it..use for example 2 inch foam board use 3 inscrews with a plastic cap..stab the screws into the cap and stab that into the foam board..Use foam board because of the moisture..to help doing this by your self..one layout the joist an the board you want to install them perpendicular to the ceiling joist Yes you can just put the foam over the dry wall just make sure you screw the foam every 12 in the field and 6 on the ends...To hang by yourself. .screw a 2x4 16 long down 2 inchs from the ceiling .do this couple place outside walls shove it in place that is your helper
 
If you don't want to mess with drywall on the ceiling, you could install 7/16" thick OSB board. Really, all you need is something rigid enough to support insulation on top. Fill in with fiberglass batts between the ceiling joists.
 
My ceiling insulation is around 24in comb first reflex the batt in the joist then batt across the joist the blown...do not block the vents on there is vent sheilds the roof should breath yes it should be ..wherdoes the heat build up go?it comes in from the vents and out the top..i would suggest to
1. Do the ceilng with ridge foam.
2 fill in between the beams with 2x4..
3.ridge foam wall .do not forget blocking .use to hang cabinets and
4, frp panels ..washable panels like used in restroom
5.any kind of insulation used like the battt will absorb moisture
6.I am not a Beer Troll
7 stay strong and brew on
 
Your building is post and beam..Which means there are 4x6 post that are tied by beams..it does not look whack...however you should see alot of carrage bolts used where they are tied together...it should look the post that are used outside wood decks..the part that carries the joist and decking...which your pic kindof shows...nothing wrong..normal for that type of construction method...But you now are trying to build your brew house?.I use the cheap chaulk as a glue then cut the reflect push it on the glue done...the chaulk will seal the drafts and the reflex will be the fisrt step in the insulation.I will use what ever thickness i can get..

Nothing whack with the construction method---the insulation is whack. Why use an insulated garage door and R4 ish foam boards around the outside, only to leave huge air gaps in the ceiling? It's like they decided to insulate, and gave up halfway.
 
ran the math, probably looking at 40 4x8 boards to cover the ceiling and walls. That's $1200 just on the foam boards--ouch!
 
Wow that is more like a small outbuild ,40 sheets x32== 1280. Or its 30 x40. That is a big shop..it would be cheaper to build a small room within the area,not the north side.My brewing area is 5x12 working great for me..that is only 60square feet...it would also be easier to heat that room..Oh yeah its not cheap..wait till you are pulling 30amp and 50 amp lines....crazy idea you could heat the floor and tile over..
 
Wow that is more like a small outbuild ,40 sheets x32== 1280. Or its 30 x40. That is a big shop..it would be cheaper to build a small room within the area,not the north side.My brewing area is 5x12 working great for me..that is only 60square feet...it would also be easier to heat that room..Oh yeah its not cheap..wait till you are pulling 30amp and 50 amp lines....crazy idea you could heat the floor and tile over..

Specifically, it's 24x28 with 10 ft ceilings. That's 3x7 = 21 4x8 panels. Plus walls, per your suggestion, 6+6+7=19. So 40, but would need a few more for the top 2' sections and the front wall. So maybe 40 was a bit of a low-ball estimate :/.

I would like the rest of the shop space to be somewhat heated as well--being able to paint or stain in the winter would be a nice help.
 
Totally agree on air sealing. The garage door seals probably need replacing, but otherwise the place looks pretty well air sealed....ignoring the huge gaps in those header boards :eek:.

I admit I'm nervous about putting up drywall on the ceiling. Never mind the physical challenge of getting that stuff up to a 10 ft ceiling, that acoustical foam was put there for a reason. Wouldn't drywall turn the place into an echo chamber? I'm thinking a work-around solution might be to use mineral wool insulation, which theoretically should hold itself in place above the foam board. But then again my goal is to do this on the cheaper side...because if budget is unlimited I would just have someone come in and spray foam the heck out of the place! :p

My entire garage is done in drywall, and never has it even crossed my mind about it being an echo chamber.

Once you get a place like this well-insulated, it becomes a joy to use. I don't have a way to heat my garage like you do--I use a propane heater if I want to do that--but given that I have 240-v power, maybe I should consider such a heater.

If you think you're going to be there for a long time, consider doing it right the first time. Yeah, more cost up front, but in the end, you'll be happier with the result.

Good luck!
 
If you have soffit vents leading into the attic make sure that you don't block them with insulation, especially with the added moisture of brewing or you will create a huge mold and mildew factory.
 
Heated floors mats and t stat..... I would start with the ceiling.. can you move around inside the attic space.if so slid the reflect in between the joist. ..
 
My entire garage is done in drywall, and never has it even crossed my mind about it being an echo chamber.

Once you get a place like this well-insulated, it becomes a joy to use. I don't have a way to heat my garage like you do--I use a propane heater if I want to do that--but given that I have 240-v power, maybe I should consider such a heater.

If you think you're going to be there for a long time, consider doing it right the first time. Yeah, more cost up front, but in the end, you'll be happier with the result.

Good luck!

Yeah, I do want to do it right the first time--part of the reason for my concern. Wouldn't want to get all the drywall up and then find out the table saw is damnably loud! :p

If you have soffit vents leading into the attic make sure that you don't block them with insulation, especially with the added moisture of brewing or you will create a huge mold and mildew factory.

For sure.

Heated floors mats and t stat..... I would start with the ceiling.. can you move around inside the attic space.if so slid the reflect in between the joist. ..

Sadly, only about 4 ft of headspace at the garage center, with no installed ladder access. I was thinking of putting a ladder in, but not sure it's even worth it. I definitely would have a hard time getting to most of the space up there.
 
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