Insulation and HardiePlank siding construction options question.
Hopefully in 2013 I'll be redoing the siding on my own home, which is really past its prime.
Currently the construction is 2x4 walls with fiberglass insul, plywood sheathing, tar paper, wood siding.
My plan will be to tearoff siding and tar paper to expose sheathing. Install housewrap and new windows. Install rigid foil faced polyiso. Install Hardie cement board siding.
I'm going back and forth between two constructions:
1. Install wood battens over the studs. (Maybe 1.5") Infill between the battens with 1.5" polyiso. Install 1" polyiso over everything with seams taped. Snap lines for the battens. Then install Hardieplank into the battens.
2. Install two layers of 1.5" foil faced polyiso over the housewrap. Tape seams of the outside layer of polyiso. Then install battens. Then install Harideplank into the battens. (I'd be left with a gap between siding and insulation.)
Should mention that I can get some of the polyiso for free and any more that I need at cost and Hardieplank at cost ... so any combination of thickness or number of layers of polyiso can be considered.
Labor will be my own time.
What's everyone's thoughts on each of the options I've presented please?
Anything else I should consider?
Thank you in advance.