Insulation question

[T2R9]

I am finishing up the insulation on my new garage. It has a full second floor which is completely insulated along with the stairwell that will be open to below.

My initial thought was to leave the ceiling below the room uninsulated to allow cooling and heat to cover the second floor. Now am having second thoughts, thinking the downstairs would maintain better if the ceiling was fully insulated. The cold\hot areas are insulated well.

Thoughts?

 

[NUTTSGT]

Personally, I'd want the spaces separate and therefore would insulate it.

 

[T2R9]

I thought about separating them but then it would require additional cooling up there. I plan on using the space as a clean room to do upholstery and dash type work. Or just add a door and leave it closed unless working in there?

Couple pictures of the stairwell and space. I do plan on running a 36k btu mini split.

 

[Fasthotrod]

Why not plan on a dual zone mini split that has two room units? That way you can insulate the top room, then set the thermostats to whatever temps you wanted in each space, and have full control of both spaces. I'd think you'd be more energy efficient that way, and wouldn't have to rely upon heat transfer and limited airflow to heat/cool the spaces. Just my two cents...

Mark

 

[CombatNinja]

If the top will not be climate controlled, you need to insulate it from the rest of the space. Speaking of which, I assume you are going to finish that wall that overlooks the lower floor or why else would we be discussing this?

I agree with Fasthotrod, why not do a mini split with two inside units on two zones? That solves your whole issue right there. Also, why did you put in shelving upstairs when the walls and insulation are not covered? You can't leave insulation exposed like that, it is not up to fire code anywhere in the country, the kraft paper facing is extremely flammable.

 

[spudley]

Without separation, you'll be battling heat going up and cool coming down constantly. I'm doing a similar build and plan to seal off the upper area completely.

 

[thammel]

I did the same thing - top room with full time stairs to it and I fully insulated the ceiling between the two for separation. However.....with an open stairwell, in the summer, you will have problems with air flow down the stairwell. I have two separate mini splits and the only way I can control thing is by blocking off the upstairs. so cool air doesn't all just roll down the open stairwell. What I did is cut rigid insulation sheets as temporary walls in the summer. It's a pain but the only thing I've found that works. In retrospect, I should have put in a door at the top. The way it's configured now I really can't do that.

So - my recommendation is to condition the attic room but close it off.

Tom