I am redoing part of a wall where water leaking in from the roof has rotten the wood. The roof is now repaired. I will replace the old boards and cedar shingles with respectively, aspenite (pressed wood chips, 4x8 panels, 1/2 inch thick) and new cedar shingles. At the store, they told me that there should be an air space between the aspenite and the shingles. This could be created with 1x3s. They also thought the panels should be covered with tyvek. 1. How important is this air-space? The rest of the house siding does not have it and it would be tough-impossible to make old and new shingles meet in the same plane. Shouldn't the shingles be nailed directly on the board behind them. With maybe tyvek and a tar paper layers? in between 2. Doesn't aspenite do the same job as tyvek as far as air-tightness is considered, if the seams are taped together. Would wind-driven rain also be stopped??? Thanks.

I need ideas on how to insulate the hardwood floor (approx. 30 inches above ground). Our home is in the very humid deep south and we have to find ways to barrier against moisture as much as possible.