So I'm looking at replacing my existing masonite siding with Hardie as a DIY project. I've done quite a bit of online research and thoroughly read through the Hardie install instructions, etc. Now I wanted to ask a few questions here and see if I can get some advice comments.
Background info on the house is it's a 30 yr old Pulte house. I haven't ripped any of the old siding off yet to verify, but as far as I can tell basically the exterior walls are drywall/2x4 frame with batted insulation/tar paper/masonite siding. Once I start pulling siding, I'll know better but based on a couple of holes I've drilled for wiring through the exterior, this is what I have.
So on to the main questions:
1. It seems like current wisdom is to go with OSB sheathing on the new houses. Any downside to adding OSB since I'll have the wall torn completely down?
2. Some of the tar paper is going to get torn off with the old siding removal, but not necessarily all. If I go back with OSB, I'll need to do a new house wrap on the outside of that. Is there a problem leaving the tar paper up under the OSB?
3. After deciding the OSB question, the next one that comes to mind is whether to add foam sheet under the hardie. 1/2" foam isn't going to make a huge difference for the wall R value, but its not that expensive and it's relatively easy to do. Once again, any issue with this? Any particular type of foam?
4. So if I do the foam, I've seen references to doing the house wrap both over and under the foam (I'm not planning to use the foam itself as the water barrier as the tyvek type wraps seem easier to work with). So does over or under really matter and should I be looking at going with faced foam as the barrier instead?
5. My house has good tree shade on about 75% of the front and back. It's generally east facing, so the sides only get incident sunlight at about a 15 degree angle. However about half of the front house gets direct sun for about 4 hours in the monring and you can definitely feel the heat in that room coming off the wall. Luckily that section of the front siding is separated from the rest of the front by an architectural design element. So I could treat it a bit differently that the rest of the front without it bein noticeable. I've been thinking about putting up radiant barrier on that portion to help cut down on the radiated heat. My options are to go with an OSB product like Techshield if I didn't do the foam, a foil faced foam if I do the foam or a RB foil. Since the RB needs an air gap, I'm assuming that all of these options need to be facing out and I need to use batten boards to attach the siding to maintain the air gap. So could I do std OSB/foam/tyvek/RB foil/batten/siding? Is there an issue with this? Is the foam overkill under the RB foil? Obviously this somewhat depends on whether you do the tyvek under the foam as you could go with foil faced foam in that case.
6. If I'm going to go with the radiant barrier on the spot that gets all the sun, should I go ahead and do the whole house? While the thought of doing battens all the way around is a bit scary, the actual fact is that if I'm going to do the foam, I'll need to snap chalk lines to mark the studs. And since I'll be working by myself on a lot of this, I don't know that nailing up battens with an air nailer is really any slower.
Anyway, thats a flood of questions covering a lot of topics.
Just as some background on me, I'm a pretty serious DIY type and have done major interior remodeling projects including a complete basement build out from bare concrete to master bedroom suite with bath. But I've never worked with siding more that just some small patches in the masonite and minor repairs to brick facade. And I like to get input from others with experience if I have never done a project of that type before.