Cost-Effective Wall Assembly
I am a builder-owner at the design stage in zone 6, coastal Maine. I am considering options on my wall assembly. I am going for green-as-I-possibly-can on a budget. I will be providing most, if not all, of the labor but am also considering labor saving choices since building my house will be taking me away from my work as a contractor.
Here are the basics of the wall assembly I am considering. I am using dense pack cellulose. Its about r-38. Moving inside to out:
1. horizontal nickel gap ship lap
2. non structural 2×3 wall
3. 4 inch gap
4. 2×4 structural wall
5. structural sheathing
7. vertical strapping
8. horizontal strapping
9. board and batten
So, I can get locally sourced hemlock and pine for 60 cents a board foot. So, b and b and shiplap are looks I like and are attainable. I will prime the exterior boards all the way around before installation.
I am considering going with plywood and hydrogap MRB and saving on the double strapping listed above. If not, I would probably do a zip system and double strap it with a rainscreen. Would appreciate feedback on this cost saving choice.
Also, will I need a moisture variable wrap on the inside of the 2×3’s? I might latex prime and paint my nickel gap in some areas, or clear coat it with an alternative to poly.
Finally, does hydrogap require a mini-rainscreen at the bottom to allow moisture to get out? The website does not seem to mention it.
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