New R60 attic requirement

[kerry lev]

Just found out Virginia's 2021 building code that went into effect last year requires R60 for unvented attics now, up from R49. I'm planning a renovation and trying to figure out how to actually achieve this without eating up all my headroom or blowing my budget. My attic currently has maybe R30 if I'm being generous, so the jump to R 60 means I either need nearly 20 inches of blown insulation or I'm looking at spray foam, which costs way more. The inspector I talked to was pretty clear there's no wiggle room on this.
Also, I find it annoying that nobody seems to talk about how much this adds to project costs. I've seen estimates that these stricter codes are adding several thousand to builds, and for retrofits it's even worse because you're working with existing structure limitations

 

[RidWan]

Try a hybrid approach, some closed cell spray foam against the roof deck for air sealing, then blown in cellulose or fiberglass to hit the total R value. That should cost less than full foam and keep more headroom. You’re right though, those newer code requirements quietly add a chunk to renovation budgets

 

[Alan]

@kerry lev hybrid is usually the sweet spot. Spray foam against the roof for air sealing, then blown insulation to hit R60. Saves money and keeps some headroom without breaking code.