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Discussion Starter #1
Hi All,

I got a detached 24x24 garage made for tinkering around cars, hanging out and smoking herb since I can't smoke it in the house with the wife and kid :)

I'll eventually put a heat pump in there so I can literally hang out in there.

I live in Canada so winters can get quite cold too.


My main issue right now is I don't know how to insulate the attic, (I was going to start with that first)





Sorry for the lighting as its early here and no sun out yet.

I'm going to use 2x4 R14 Rockwool for the entire main level.
I'm presuming I need rafters like this as I do have soffits and I want air flow? https://www.homedepot.ca/en/home/p.22-inch-x-4-ft-rafter-vent-10-pack.1000136854.html

Then do I just put more rockwool ontop of it or what?
There is no ridgevents or anything either.

Also, any ideas on what you'd use the attic space for? Should I put plywood down and use it for storage?

Thanks everyone!
 

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Exterior Construction
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The bottom chords of trusses aren't designed to carry weight to be perfectly honest as it relates to your storage question. If you have some intermediary walls throughout the garage that are effectively supporting the load, then sure...you are fine on the storage part. I would be very cautious of putting any weight up there otherwise.



On the insulation question, you have two options: Vented or un-vented. If you are going to be running just a flat ceiling across the bottom of the trusses, a vented assembly (must have intake and exhaust air) is probably easiest and the cheapest to do.



There are some pictures of examples here on this pdf.



https://www.finehomebuilding.com/pdf/021221068.pdf
 

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Discussion Starter #3
The bottom chords of trusses aren't designed to carry weight to be perfectly honest as it relates to your storage question. If you have some intermediary walls throughout the garage that are effectively supporting the load, then sure...you are fine on the storage part. I would be very cautious of putting any weight up there otherwise.



On the insulation question, you have two options: Vented or un-vented. If you are going to be running just a flat ceiling across the bottom of the trusses, a vented assembly (must have intake and exhaust air) is probably easiest and the cheapest to do.



There are some pictures of examples here on this pdf.



https://www.finehomebuilding.com/pdf/021221068.pdf
Thanks for the response and thanks for the pdf, great info! From reading it, if I want to insulate the attic I'd have to put the vents in, then put insulation ontop of it.. then close it in whilst making sure there is insulation on top.

Can I use those 1x6s for anything, are they there for any specific reason?(dumb question)
 

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retired framer
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Start with an attic access between the trusses 30" long and 16" high so you will be above the level of any insulation. OSB and 2x4 around the outside is good. Then around it fill in the spaces between the strapping. Start with 2 2x4s between the trusses 31 inches apart. Square to the trusses. Then you want to deal with venting at the peak and the soffits and air chutes at the soffits. No storage.
 

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Discussion Starter #5 (Edited)
Start with an attic access between the trusses 30" long and 16" high so you will be above the level of any insulation. OSB and 2x4 around the outside is good. Then around it fill in the spaces between the strapping. Start with 2 2x4s between the trusses 31 inches apart. Square to the trusses. Then you want to deal with venting at the peak and the soffits and air chutes at the soffits. No storage.
Hi Neal, thanks again for responding to one of my questions again :D !

I can't visually picture what you're trying to tell me.

So, make an attic access (probably back of garage).
OSB and 2x4 for the ceiling of the garage itself?

So attach 2x4s to the bottom of the truses and attach the OSB to that?
 

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retired framer
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Hi Neal, thanks again for responding to one of my questions again :D !

I can't visually picture what you're trying to tell me.

So, make an attic access (probably back of garage).
OSB and 2x4 for the ceiling of the garage itself?

So attach 2x4s to the bottom of the truses and attach the OSB to that?
Anywhere that will be convenient to put a ladder and not to close to the sides where you want have room to climb up. You want an open in the ceiling with high sides up in the attic.
Your trusses are somewhere around 22 1/2 inches apart cut 4 2x4 to fit that and 2 pieces of OSB 22 1/2 x 16 2 OSB and 2 at 30x 16 for the sides of the box and 2 2x4 34" long.
the 2x4 wrap around the outside at the top. and between the trusses at the bottom
 

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Discussion Starter #8
Great info Neal, thank you.

One last question for you, if I'm not going to bother with the attic of the garage I might as well skip insulating it right?
 

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Great info Neal, thank you.

One last question for you, if I'm not going to bother with the attic of the garage I might as well skip insulating it right?
If you are heating the garage you want insulation above the ceiling, insulating the roof cost way more and is hard on the shingles.
 

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Discussion Starter #10
Okay,

To make this clear,
I'll follow Windows on Wash and put rafters up and insulation right infront of them like the pdf he showed..then I'll make the attic access as you suggested Nealtw and make sure that is done right, then I can buy a boatload of OSB 1/4 4x8 Oriented Strand Board to cover the entire ceiling and walls once everything is insulated. Can I just screw the OSB to those 1x6s that are already there?

Can I just shove any old insulation up in the attic or should I continue to use Rockwool throughout?

Thanks.
 

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retired framer
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Okay,

To make this clear,
I'll follow Windows on Wash and put rafters up and insulation right infront of them like the pdf he showed..then I'll make the attic access as you suggested Nealtw and make sure that is done right, then I can buy a boatload of OSB 1/4 4x8 Oriented Strand Board to cover the entire ceiling and walls once everything is insulated. Can I just screw the OSB to those 1x6s that are already there?

Can I just shove any old insulation up in the attic or should I continue to use Rockwool throughout?

Thanks.
What ever insulation that you like will work and you can discuss that with people who have preference.
If you will be doing some living and heating in the space, You want to stop as much warm moist air from leaking into the attic, so if you are using paneling you want a vapour barrier first. If you were doing drywall you might skip that.
The air chutes get stapled to the underside if the roof deck and between the chute and the top of the wall you want to fill that little space with some kind of batt to close it off, So if you or others ever use loose fill insulation it will not fall out into the soffit area and plug everything up.
 

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Here is what I did in my detached 26 x 28 man cave . I am no expert just an average DIYer . My garage started as a pole barn so I only have 6 trusses spaced evenly apart but they are 2 x 4 like yours . The first thing I did was staple 4 ' wide roll reflective foil to the bottom of the roof trusses up near the roof deck . In your case that would give you an " air space " roughly 23 " wide by 3.5 " deep by the length of the truss from the bottom to the top . This foil is relatively inexpensive and the theory is it reflects a major portion of heat/cold back to the roof deck so it doesn't get into the attic space . I do have 28 ' of soffit vent on each side and a full length ridge vent , this is VERY important .

In my case my finished ceiling is metal roof panels , they are lighter than sheetrock , already painted and offer some fire break . I went with white and screwed right to the bottom of the rafters there was no sag between rafters . Once the ceiling was in place I layed one thickness of kraft faced R19 insulation on top of the metal . Sometime down the road I will add a 2nd layer of unfaced insulation in the opposite direction to get to at least R38 . I am in north GA. so don't have the cold you do but I have very high heat and humidity . I am heating and cooling with a 24K mini split for about $10.00 a month , the heat I keep at 61 degrees the AC I keep at about 78 when I am not in the garage . I adjust the temps as needed when I am in there . I also have R19 wall insulation .

In your case spend the time to eliminate any draft areas with caulk/foam before you do anything . I personally would remove those 1 x's under the rafters , whatever you decide to use as a ceiling the screws will hold much better in the 2x4 than the 1x .
 

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Discussion Starter #13
Here is what I did in my detached 26 x 28 man cave . I am no expert just an average DIYer . My garage started as a pole barn so I only have 6 trusses spaced evenly apart but they are 2 x 4 like yours . The first thing I did was staple 4 ' wide roll reflective foil to the bottom of the roof trusses up near the roof deck . In your case that would give you an " air space " roughly 23 " wide by 3.5 " deep by the length of the truss from the bottom to the top . This foil is relatively inexpensive and the theory is it reflects a major portion of heat/cold back to the roof deck so it doesn't get into the attic space . I do have 28 ' of soffit vent on each side and a full length ridge vent , this is VERY important .

In my case my finished ceiling is metal roof panels , they are lighter than sheetrock , already painted and offer some fire break . I went with white and screwed right to the bottom of the rafters there was no sag between rafters . Once the ceiling was in place I layed one thickness of kraft faced R19 insulation on top of the metal . Sometime down the road I will add a 2nd layer of unfaced insulation in the opposite direction to get to at least R38 . I am in north GA. so don't have the cold you do but I have very high heat and humidity . I am heating and cooling with a 24K mini split for about $10.00 a month , the heat I keep at 61 degrees the AC I keep at about 78 when I am not in the garage . I adjust the temps as needed when I am in there . I also have R19 wall insulation .

In your case spend the time to eliminate any draft areas with caulk/foam before you do anything . I personally would remove those 1 x's under the rafters , whatever you decide to use as a ceiling the screws will hold much better in the 2x4 than the 1x .
Your Man cave sounds awesome.

Thanks for the recommendations, actually do you have a reference as to what a metal roof panel looks like is it something like this? https://www.homedepot.ca/en/home/p.cor-pvc-12-feet--white-opaque.1000412024.html

Also, I tried to use gap filler in my garage when it was -10c out and it failed to work properly lol.

Thanks again for your input and help!
 

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The Home Depot product you listed is garbage in my opinion . You want real metal panels I like the R style . See link below this represents what an R style looks like , the link is the local to me company that I purchased from . I like this type of panel for a ceiling for several reasons .

1.The panels come painted so once installed you are done . I went with white .

2.Unlike sheetrock there is no taping/sanding/priming/painting .

3.The white panels reflect lighting very well . I went with perimiter 4 ' long LED lights mounted about 6 " below the panels it's like working on the sun :biggrin2:

4.Your local metal shop will cut to whatever length you want . In my case I went with panels long enough to have just one seam in the middle that overlaps by about a foot .

5.One man can install these by himself ( I did ) by renting a ceiling lift . Just balance the panel and crank it up . Doing one panel at a time it's very easy to hit the studs with the screws .

6.DISCLAIMER: Check local codes to see if this is an acceptable product to be used in your area . This may or may not meet fire code .

Hope this gives you a rough idea why I suggested it . Good luck with whatever you choose .


http://bmmetalroofing.com/r-panel-metal-roofing/
 

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Oops a few more things :biggrin2: . Some folks say the room will sound tinny with a metal ceiling I did not have that result . Sounds like any other room to me . And cutting it is a little harder than doing sheetrock . I found that using a good set of snips and a metal cutting blade in a circular saw worked best . Very noisy so use hearing protection and safety glasses ! And finally installing that first panel sets the tone for the entire install it HAS to be square or as close as you can get it . When you overlap the panels there is a little wiggle room for adjustment but you want to end up at the far wall with a cut piece of aprox. the same size end to end if that makes sense . I installed a 1x6 at the top plate to have something to screw to on the perimeter . My ceiling came out great , sounds good and reflects light very well . And adds minimal weight to the trusses .
 

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Here is what I did in my detached 26 x 28 man cave . I am no expert just an average DIYer . My garage started as a pole barn so I only have 6 trusses spaced evenly apart but they are 2 x 4 like yours . The first thing I did was staple 4 ' wide roll reflective foil to the bottom of the roof trusses up near the roof deck . In your case that would give you an " air space " roughly 23 " wide by 3.5 " deep by the length of the truss from the bottom to the top . This foil is relatively inexpensive and the theory is it reflects a major portion of heat/cold back to the roof deck so it doesn't get into the attic space . I do have 28 ' of soffit vent on each side and a full length ridge vent , this is VERY important .

In my case my finished ceiling is metal roof panels , they are lighter than sheetrock , already painted and offer some fire break . I went with white and screwed right to the bottom of the rafters there was no sag between rafters . Once the ceiling was in place I layed one thickness of kraft faced R19 insulation on top of the metal . Sometime down the road I will add a 2nd layer of unfaced insulation in the opposite direction to get to at least R38 . I am in north GA. so don't have the cold you do but I have very high heat and humidity . I am heating and cooling with a 24K mini split for about $10.00 a month , the heat I keep at 61 degrees the AC I keep at about 78 when I am not in the garage . I adjust the temps as needed when I am in there . I also have R19 wall insulation .

In your case spend the time to eliminate any draft areas with caulk/foam before you do anything . I personally would remove those 1 x's under the rafters , whatever you decide to use as a ceiling the screws will hold much better in the 2x4 than the 1x .
I like the metal roof but do you notice any condensation
 

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No condensation on my metal roof as it is protected from the warm air in the garage by R19 insulation in the ceiling AND the radiant barrier stapled to the perlons . Plus I have full length soffit vents on both sides and one full length ridge vent .
 
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