Exterior insulation behind stone chimney
We are planning to add exterior insulation to an old house. House has 2 layers of siding. There is a large external field stone chimney on the east side and the siding runs up to this. I don’t know if this is the same for the inner layer of siding; could be that the siding was installed and then the chimney built. This inner layer has lead paint and may be left in place when adding the exterior insulation (likely spray foam). If removing all siding to access the wall sheathing gives us options for insulating the wall cavity behind the chimney, seems like we should consider this.
House had formaldehyde insulation blown in (70s). Not sure if they did the wall cavities behind the chimney – don’t think so since I don’t see drill holes on the inside of the house where the chimney goes up the wall.
What options should I consider for insulating the wall behind the chimney? Tear it down as much as possible and add a new metal chimney seems extreme.
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