Attic - general insulation question

My son bought a house which has an 800 sq ft attic. The attic was supposed to be finished but never was except for plywood on the floor. The insulation is up on the roof rafters with the paper facing down. There are baffles from the soffit to the ridge vent. The issue is that in the summer, the bedrooms below were hot, and now that it has cooled off, they are cold. My thinking is that there is transfer through the ceiling in the bedrooms, and there should be insulation between them and the attic so that there is a barrier (heat can't escape up in winter or radiate down in summer).

I've never seen an attic that has insulation in both places (floor and rafters). Is that legit?.

 

It should be in one place or the other but not both. A finished attic would be conditioned space (climate controlled) and the insulation would be above. An unfinished attic is not climate controlled and the insulation would be in the floor.

 

What is the temperature in the attic? As X stated, this needs to be conditioned if the insulation is in the ceiling/rafters.

 

The attic isn't conditioned space, so the winter temp is whatever it is outside + a few degrees from leakage and the summer ....... well.......you know.

New project.

 

OK, then the insulation should be in the floor, not the rafters.

 

That's not a finished attic then. It just like an other attic... unconditioned storage space... and yes, the insulation should be in the floor. By putting a floor down you are compromising the amount of insulation that SHOULD be up there. Attic floors ought to have R-49 more or less.

See map.

One way around that is to build an elevated floor and small staircase above the insulation for storage purposes. If that's not possible, you could look into installing a minisplit up there in order to have conditioned space up there. Then you could rightly finish the attic, assuming the floor was engineered to be living space.

 

I think we are just gonna pull the insulation from the rafters and put it where it needs to be. Thanks for the confirmation.

 

One more question - why is it not advisable to leave the insulation on the rafters and just add new insulation between the plywood floor and the drywall ceiling?.

 

The attic is going to be hot in the summers, and you should want to ventilate it, not insulate it and hold the heat and humidity inside.