Fiber cement siding over existing plywood siding
Our 1970s house is constructed using plywood T1-11 siding that we think also functions as sheathing of the house. The siding is in need of repair and repainting, so we thought this is a good opportunity to just replace the existing siding with new fiber cement siding. In talking to several people, we were told that we can install fiber cement siding over the existing plywood. The installer we spoke with suggests they’d wrap the existing plywood siding with WRB, and install the new Hardie siding on top of it. I was wondering, is this standard practice, and if so, are there any disadvantages or concerns that we should be aware of taking this approach?
We are also interested in upgrading insulation of our walls at the same time (possibly adding rigid foam insulation below the new siding). Is this an advisable approach, or would we need to install new sheathing if we want to add insulation?
Thanks in advance for your help. As you may have surmised from above, I’m not well versed with construction techniques and I’m looking at this from a homeowner’s perspective.
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