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Insulating and Ventilating Detached Garage with Hip Roof

viggs79 | Posted in Energy Efficiency and Durability on

Good Morning All.

I am looking to insulate my detached garage. It is a 25×25 structure with a pyramid hip roof. Currently, the roof is not insulated at all and there is no roof or soffit ventilation. Also, the “attic space” is all open. No wall or ceiling finishes.

I would like to insulate between the roof rafters and leave the ceiling joists open. I use the joists for light storage. The items are awkwardly shaped and if I were to close in the joists, these items would not fit through an attic access.

I am in central Ohio so we can have hot summers and very cold winters. I am concerned about condensation on the roof sheathing as I would also like to add a mini split hvac unit to keep the space somewhat comfortable when in use.

My questions are:

1. Is spray foam an option here?

– I have seem all kinds of info for and against and it is a bit overwhelming. Also I cannot get pros to come out and talk to me about it because the job is so small.

2. If I choose to vent the soffits, what type of vents should I use for the air to exit if I am insulating the rafters?

– I don’t know I like the idea of hip vents. I have read that these tend to leak at a much higher rate than ridge vents if not done right. If I add roof vents just to vent the longer rafter channels

3. Is my desire to insulate only between the rafters a lost cause and should I just create an attic space and insulate the ceiling?

Thanks in advance!

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