2 car garage insulation

[Lovthebass]

I am insulating my new 2 car detached garage with a room roof truss on the second floor. The garage is 25X25 with a 10’ ceiling. My question is should I insulate the ceiling on the 1st floor also? Or should I just insulate the walls on the first floor and the roof trusses on the second? I am putting sheetrock over the walls and ceiling on the ground floor. The roof is made of 2x6 trusses. I will be spending most of my time working on the ground floor. Im looking for the best way to do this, but don’t want to do anything unnecessary. Here are some pics-

 

[loganb]

What are the plans for the 2 different levels? What are the plans for heat/cool? How often do you plan to be out there working? May have missed it in your profile but where are you located?

 

[ddawg16]

Logamb asked good questions.
Im inclined to say, insulate the floor.

If the lower level is open and the upstairs is being usedas say a bedroom or office, it will be easier to heat or cool that space

 

[Lovthebass]

What are the plans for the 2 different levels? What are the plans for heat/cool? How often do you plan to be out there working? May have missed it in your profile but where are you located?

The ground level will be for working on projects and cars, I will be spending time in there mostly on the weekends. The second floor will be used for storage right now but in the future I would like to take half of it and use it as a music studio. I have a 10,000 btu heater on the ground level so I can work on things during the winter. The garage is super hot most of the time, it‘s usually uncomfortable working In there in the summer. I am in New Jersey.

 

[jlv03]

I'd be inclined to insulate the floor (1st floor ceiling), more for the noise than anything!

 

[loganb]

If it was my space based on what you shared in no particular order:

• Mineral Wool Insulation in 1st floor ceiling to provide some insulation but also substantial noise deadening in support of future plans for upstairs, Rockwool Safe 'N Sound or similar
• Insulate the walls on 1st level with batt or blown in insulation or if have the money spray foam as it looks like you've got 2x6 framing so 1-2" of spray foam for air sealing then R11/R13 batt on top of that would be hard to beat
  • If doing spray foam and can do it, insulate the upstairs and roof deck at same time as your cost per sq ft of insulation will be better doing it all at once vs 2 different trips months or years apart...if just doing batt or blown in everywhere the cost savings aren't as big
• Cover the ceiling, then do walls with material of your choice. If it was my place I'd put metal liner panel on the ceiling, walls would be either drywall or plywood depending on exact usage and cost of material at the time. Hanging rock on walls is much easier than ceilings for the avg garage enthusiast, but many (including myself) would just pay to have it done
  • Doing ceiling first will help you keep the conditioned air where you want it and give greater thermal benefits vs covering walls(assuming walls are insulated)
• Install a mini split that is capable of 2 zones, 1 for garage and one for upstairs. You can install that 2nd zone when you're ready but planning for it now makes that future add on much easier if it's installed immediately

Another thing to consider depending on usage would be install a thermal "barrier" door on the stairwell upstairs. Especially in the winter if you're not using the upper area and doing a lot in the garage level and keeping it comfortable that heat is going to escape up the stairwell and into the un-used space. If you're not using it often even a basic sheet of foam board over the opening could make a big difference in keeping the heat where you want it. And regardless of what season it is, you need air movement for good temp control so a fan or two to keep air circulating and enable a consistent temp across the space is important.

 

[Lovthebass]

If it was my space based on what you shared in no particular order:

• Mineral Wool Insulation in 1st floor ceiling to provide some insulation but also substantial noise deadening in support of future plans for upstairs, Rockwool Safe 'N Sound or similar
• Insulate the walls on 1st level with batt or blown in insulation or if have the money spray foam as it looks like you've got 2x6 framing so 1-2" of spray foam for air sealing then R11/R13 batt on top of that would be hard to beat
  • If doing spray foam and can do it, insulate the upstairs and roof deck at same time as your cost per sq ft of insulation will be better doing it all at once vs 2 different trips months or years apart...if just doing batt or blown in everywhere the cost savings aren't as big
• Cover the ceiling, then do walls with material of your choice. If it was my place I'd put metal liner panel on the ceiling, walls would be either drywall or plywood depending on exact usage and cost of material at the time. Hanging rock on walls is much easier than ceilings for the avg garage enthusiast, but many (including myself) would just pay to have it done
  • Doing ceiling first will help you keep the conditioned air where you want it and give greater thermal benefits vs covering walls(assuming walls are insulated)
• Install a mini split that is capable of 2 zones, 1 for garage and one for upstairs. You can install that 2nd zone when you're ready but planning for it now makes that future add on much easier if it's installed immediately

Another thing to consider depending on usage would be install a thermal "barrier" door on the stairwell upstairs. Especially in the winter if you're not using the upper area and doing a lot in the garage level and keeping it comfortable that heat is going to escape up the stairwell and into the un-used space. If you're not using it often even a basic sheet of foam board over the opening could make a big difference in keeping the heat where you want it. And regardless of what season it is, you need air movement for good temp control so a fan or two to keep air circulating and enable a consistent temp across the space is important.

Thanks Loganb, that is alot of information. I’m not going to be able to do spray insulation, I can’t afford it unfortunatel. I’m going to do it myself with fiberglass. I’m going to do R-21 on the walls and R-30 on the ceiling downstairs. Upstairs I’m going to put R-30 where it will fit, R-21 on the 2x6 truss areas. This is the best I could come up with considering what I can afford to do. I’m definitely going to do some kind of barrier for the staircase, I just need to figure out what but the foam board sounds like a good idea!

 

[ddawg16]

For the stair barrier, make a door the size of the opening....put a hinge at the far end and either u a counter weight or spring load it