Question for the construction experts...

FZ1inTX

FZ1inTX

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Insulating the garage ceiling?

I own a detached 24'x24' garage. The doors are insulated aluminum-clad and will be sealed fully next weekend. The walls are all fully insulated and sheetrocked. I've still got to trim out the windows and doors inside and insulate the small spaces around them.

My question is, what would be the best way to insulate the ceiling without it being 100% permanent? The garage has loft rafters and is a cape style. This left me with some knee-walls up there after I closed up the loft for storage (so things wouldn't fall out onto the vehicles). I use the leftover rafter space to store items like PVC pipe, spare siding, some wood, etc. I also have several things suspended from the rafters but those can be worked around easily.

I'd like to insulate it enough to hold some heat in for only when I want to work out there in the winter. I'm going to install a small 20k BTU wall-vented gas heater with a blower but I don't want the heat to head up into the loft and out the ridge-vent.

What are some options? Here was one thought I had and tell me if this is feasible? screw 1"x3" strapping across the bottoms of the rafters to provide support for the 2" rigid foam board and fill each space between the rafters with the foam panels? It would take 3 eight-foot panels to stretch from one side to the other per bay, thus 36 panels and she's covered. If I do this, I can then, in the summer, lift the end panels up a bit and slide them on top of the center panel to allow heat to escape when I don't want it trapped. This also still allows me to use the rafter space for the stored items and make them accessible.

Thoughts? Or, is there a better way, maybe cheaper way? I added up the costs for this method and it came to $600 to accomplish the task. This doesn't include the heater.
 
Man Eric, You already figured it out. I had only read the first two sentences and was going to tell you to go with the 2" rigid. You read my mind. I'm not sure what your joist spacing is but 36 panels 2'x8' each will do the trick. We sell them at 7 bucks a board. Why 600 dollars to complete?
 
a picture would be better to offer advice....b/c I'm envisioning it as below

attachment.php



where the space would be open to keep your present storage available which would lead me to insulate the perimeter.....with the joist running side to side....but I'm pretty drained from the days activities...
 
Thanks guys! Ok, I admit, a pic would help a lot. Here's a shot with some arrows added. This is from the day they erected the garage.

attachment.php
 
My thought that Billy has backed up was 1"x3" boards going in the direction of the arrows, about every 3 feet then slide the foam board up on top of these and snug them up then make the final one a cut to fit.

The rafters are 2' OC.

Billy, the cost was over $500 for the foam board here. They charge $13.28 per foam board without the fire protection and I wanted the fire protection so it was $15.44 per board. That was $555.00 just for the foam. Throw in the strapping and some expaning foam to seal around things I'd have to cut to fit and we're over $600. Now, $7.00 a panel? I'd have bought them on the spot! :tup:
 
FZ1inNH said:
My thought that Billy has backed up was 1"x3" boards going in the direction of the arrows, about every 3 feet then slide the foam board up on top of these and snug them up then make the final one a cut to fit.

The rafters are 2' OC.

Billy, the cost was over $500 for the foam board here. They charge $13.28 per foam board without the fire protection and I wanted the fire protection so it was $15.44 per board. That was $555.00 just for the foam. Throw in the strapping and some expaning foam to seal around things I'd have to cut to fit and we're over $600. Now, $7.00 a panel? I'd have bought them on the spot! :tup:
Click to expand...

Boy! There must be a big styrofoam shortage in New Hampshire!!
 
Haileyan said:
Why not just tac/staple the foam board to the rafters from below?
Click to expand...

I could Brad, but I still want to be able to lift and push the ends aside so heat can dissipate in the summer.

Here's the rough paint version: The red is the walls and the rafters. The black with the pink in the middle is the fire resistant foam board and the small green blocks are the 1x3 strapping. This is a cross-section of the garage at the ceiling level.

attachment.php


Thanks!!
 
Heck of a time for the forum to disappear on me... I had a nice long message typed out and clicked submit... couldn't load theforum, couldn't go back to get what I typed. Bummer!

So, I'm thinking of this for a heater (or a similar product), with the blower... thoughts?

- Harbor Freight Tools - Quality Tools at the Lowest Prices

This is a vent-free so I'll have to be careful and make sure I have the bottom of one window slightly cracked and the top of another cracked if I will be in there for a long time.

I thought of the natural gas forced hot air, but that creates a dust problem. Not good for doing finish work. The one above can work without the blower though.

Last is the radiant tube heater which is the most efficient and is great because it heats objects like the floor that will hold the heat. Drawback is expensive and you cannot work within 4' of it.

I think the cheap choice will do so long as I'm not out there for more than 4 - 6 hrs at a time or get a device to monitor the oxygen levels.
 
Another option for heat... Since a flame heater can cause problems if I am working on something with a lot of fumes... How about this?

Qmark BRH562 Portable 240-Volt 5600 Watt Electric Heater

Clean, quiet but no idea how much electricity this will eat per hour to warm up the garage. It's not like I'll be out there every day or even every weekend but it sure would be nice to have heat to do projects in the winter months..... like modding the bike!
 
ok....temp fix....just use some 3" screws with some metal washers to give the head a larger surface area to bite so it does not go through...a variation to Brad's comment

you'll also need to block off the soffit......if that is indeed the way it presently sits, b/c all your warm air will go right outside....even if you do go to the wall, you'll need to put something there....
 
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FZ1inNH said:
Heck of a time for the forum to disappear on me... I had a nice long message typed out and clicked submit... couldn't load theforum, couldn't go back to get what I typed. Bummer!

So, I'm thinking of this for a heater (or a similar product), with the blower... thoughts?

- Harbor Freight Tools - Quality Tools at the Lowest Prices

This is a vent-free so I'll have to be careful and make sure I have the bottom of one window slightly cracked and the top of another cracked if I will be in there for a long time.

I thought of the natural gas forced hot air, but that creates a dust problem. Not good for doing finish work. The one above can work without the blower though.

Last is the radiant tube heater which is the most efficient and is great because it heats objects like the floor that will hold the heat. Drawback is expensive and you cannot work within 4' of it.

I think the cheap choice will do so long as I'm not out there for more than 4 - 6 hrs at a time or get a device to monitor the oxygen levels.
Click to expand...


You'd probably get away with this H.B. unit. You could always fire it up a half hour or so before going in to work, and then shut it down after a couple of hours. Being insulated now, the garage should hold the heat in for another hour or so. All in all, you'll come in at about 900 bucks for the whole deal. Not bad if you ask me. Oh, and there's propane to buy as well.
 
BroHay said:
ok....temp fix....just use some 3" screws with some metal washers to give the head a larger surface area to bite so it does not go through...a variation to Brad's comment

you'll also need to block off the soffit......if that is indeed the way it presently sits, b/c all your warm air will go right outside....even if you do go to the wall, you'll need to put something there....
Click to expand...

Well, the 1x3 strapping is very cheap so that is likely a good option to stick with and will be quick to install. :tup:

So, I should screw in some boards to the top plate near the soffits? Sort of like bridging in rafters but just at the ends so the foam can butt up to it. I'd put some thin foam strips between it and the wall before screwing in to seal that off. Here's another paint picture, rough but I think this is what you mean?

attachment.php
 
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I'm also thinking, if I buy the foil-faced foam, I can just use the reinforced aluminum foil tape at the seams. I can, at the ends where the blocking boards are installed, just set a couple drywall screws at the top edge to act as upper cleats so the ends of the panels don't lift at all.

Anyone see any big issues with this design? I know the panels would have to be a pretty tight fit but once in place, the middle ones would never move. The end panels would move in the summer if needed but who knows, maybe it will actually keep the garage cooler in the summer with them in place?

I guess my main concern with this is the tight fit. I can always plug cracks with the tape or some spray-in foam, eh?

Seems that electric heater is the best choice, especially since I plan on doing to cabinet finishing and the fumes can be extra dangerous with the gas heaters. Can still be that way with the electric heater too but less likely. This way, I don't have to worry about buying fuel or running a gas line from the house to the garage (unsure if that is even allowed here). It will run up the electric bill but if I plan my projects properly, I shouldn't be out there many times over the winter.

would be nice to be able to do some mod work on the bike without freezing though! :D
 
This is what I was thinking... i'd use the rigid foam up in the trusses.. seal everything up nice and tight... hell, since it's a small place, maybe even get some R19 fiberglass to put in above the rigid foam... insulate the hell out of the roof... then, your ceiling "storage" is still open... you can either use rigid to cover your apex vents, or if it were my project, I'd get rid of the traditional apex vents, replacing them with apex fans with weighted louvers. .. then, it gets hot, you hit the fans and cool the place down... but, if you insulate the roof, it'll help in keeping the summer heat out just as well as keeping the winter cold out.
 
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