Hi all,

ive posted a few times here about my project to finish the attic. So far I’ve:

Insulated the rafters (with air gap and continuous 2” rigid board polyiso to underside of rafters). 

Pulled up the old subfloor boards and sold them to offset some costs. 

Run some new electrical to downstairs and set up for electrical to attic. 

Had a plumber lower and close off some iron pipe that was poking up about 3 inches above the subfloor on either end of the attic (presumably to put in radiators later on if desired). 

Hauled up OSB subfloor sheets and 5/8 drywall sheets (rented a scissor lift for that—man was that helpful). 

now it’s time to lay down the subfloor. Here are some questions I have for the experts:

1. My plan is to screw 2.5 inchers every 6-8 inches on the joists. I’d love to avoid glue—honestly it’s intimidating to think how permanent it is.   Is this a big mistake, or acceptable cut?

2.  I’ll leave 1/8 inch where subfloor panels butt, do I need to leave a similar gap in T&G?  How do I know when the long ends are properly spaced?

3.  I’ve asked this question before, and the answer has been no, but just want to throw it out one more time. Should I throw some batt insulation down before I close up that floor?  My logic is we’ll most likely spend most of our time in the floors below the attic. And the attic itself will be conditioned independently with mini splits when in use.  I’m thinking insulating the attic floor would help reduce our energy costs. 

4. Any other tips for dummies like me would also be appreciated!

Thanks!!!
Matt