keeping the garage comfortable

[grizzlebar]

Background: about six months ago I wrapped up the construction of a detached 20x24 garage with 12ft ceilings. At the time of construction, I insulated the walls and covered them with drywall but elected to leave the ceiling unfinished.

The garage gets quite warm during the day, even with the ridge vent that's in place. To combat the heat, can I get by with just a gable fan or do I need to commit to drywalling/insulating the ceiling?

 

[yeldogt]

Yes

You will never get enough flow thought the vent and it can only cool down to temp outside --Air temp inside.

You will have radiant heat from the roof deck.

Is it a truss or can you do cathedral?

 

[grizzlebar]

Truss

 

[k1rodeoboater]

You'll want a radiant barrier on the underside of the roof sheathing. My house was built with sheathing that had it pre-attached. How useful that is I don't yet know. I have been meaning to put a temp sensor up there to monitor the attic temps so I can determine if I can put my NVR up there or not.

How tightly sealed is your garage? Are your soffits vented? If it's tight, and the soffits aren't vented, a fan isn't going to do a whole lot of good to get air movement through the structure. As has already been stated the best you'll get is a temp equal to the ambient air temp, usually slightly warmer.

 

[grizzlebar]

Soffits are vented and the garage is well sealed. Small gap at the bottom of one side of the garage door due to uneven cement.

With the ceiling being open I’m not as worried about the temp in the “attic” as I am with the temp in the whole garage

 

[ripperd]

If you separate the attic space from the main fllor with drywall that will help quite a bit. Some of what you feel is radiation from the underside of the hot roof deck.

After doing that, I would blow in some insulation up there.

 

[grizzlebar]

I think I’ll go that route... eventually. Putting it off because of the price honestly.

Will putting in a roof turbine or gable vent fan help in the mean time?

 

[grizzlebar]

There’s the overhead for anyone wondering

 

[nutjob]

We moved into this house 3 years ago, attached garage 23' x 24' no insulation in walls or ceiling. Last summer the garage was very hot for the same reason you are experiencing. I hired a insulation company and they installed baffles and blew in about 12". HUGE difference this summer! Garage was at least 10-15 degrees cooler than outside during the 95-100 degree days we recently had.

I use a 5k electric heater for the winter and again the space heated up faster and stayed comfortable longer

Kevin

 

[jbwilkins]

I think I’ll go that route... eventually. Putting it off because of the price honestly.

Will putting in a roof turbine or gable vent fan help in the mean time?

Anything that 'vent's' the space more will help, but it will be minimal, you're really only replacing the hot air in the 'attic' with less hot air from outside...........

 

[Bretny]

Your wasting your time trying to keep that place cool with no attic insulation. You should have done that first before the walls, it would have paid off better.

 

[grizzlebar]

Your wasting your time trying to keep that place cool with no attic insulation. You should have done that first before the walls, it would have paid off better.

 

[Bretny]

Your welcome.

Im sure you can see where im going with this? Insulate the attic and go from there.

 

[TurnipTruck]

Those are not trusses.

Insulate the ceiling and your garage will be warmer AND cooler.

 

[Falcon67]

I think I’ll go that route... eventually. Putting it off because of the price honestly.

Will putting in a roof turbine or gable vent fan help in the mean time?

Not much if any. Only ceiling material, seams taped or caulked including the intersection with the walls and insulation will block the heat. Since you used plan OSB and not reflective decking, you're radiating about 20F more than otherwise. Radiant barrier under the rafters would help but not near what a ceiling will do.