Recommendation on insulate att garage ceiling - Michigan

[ED26]

I have 2x4 rafters which are 2' on center.

What is best way to insulate..not looking to blow insulation, would prefer a combination of batts or roll type insulation.

1) Put standard fiberglass insulation that's appropriate for the climate (probably R-38) between the joists. Since this insulation will be 12 inches thick, the top will sit above the joists, but will not cover them. Some amount of thermal transfer will still occur through the joists themselves.

2) Put insulation meant for 2x4 R13 framed walls between the joists (which will be the same height as the joists), then lay a perpendicular layer of attic insulation (maybe R-30) on top of them.

 

[burleyfarm]

No. 2


Sent from my iPhone using Tapatalk

 

[ED26]

thats what i was leaning towards doing, just wanted to make sure! thanks for the help

 

[FDNYRETIRED]

I live in NY and had my house elevated. My architect plans called for R-30 rolled between the joists. Then R-30 closed cell pink board over the joists and then 5/8 sheetrock mold resistant and fireproof. I have a full home pressurized fire wet system. So he wanted to make sure the pipes stayed warm in the ceiling. I also wrapped the pipes. My walls were done with ICF fox blocks. But because of the Smart Flood Vents. 4 of which have the louvers for air exchange. You should feel the drafts coming in. They are suppose to close with bimetal springs has temp changes. But it has been 35*F at night and they are not fully closed. No matter what anyone says there is no way without putting covers over those flood vents to keep the garage from having drafts and being cold at the floor. I have 8 of them. 4 insulated and 4 vented. But I also think #2 is the way to go for you. Mine is just over protection in my ceiling IMHO.

 

[burleyfarm]

thats what i was leaning towards doing, just wanted to make sure! thanks for the help

2 will help stop the thermal transfer. Do you have truss webbing that will get in the way? If you do you could do blown in on top of the r13 or blow in full depth cellulose.


Sent from my iPhone using Tapatalk

 

[ED26]

2 will help stop the thermal transfer. Do you have truss webbing that will get in the way? If you do you could do blown in on top of the r13 or blow in full depth cellulose.


Sent from my iPhone using Tapatalk

i have some webbing, i will do my best to keep insulation tight against it