Hello

  I was interested in your dicusion on the double wall. The way I would build this wall is. The first wall would have two layers  of

1 1/2″ of poly foam. then I would layer 5/8″ sheeting on outside with a layer of tyvek. then on the outside I would layer 2 1″ sheets

under the siding. On the inside I would layer a 1″ poly sheet horizintally. This would be covered by a 1/2″ Gyp board painted.

Then then the inner wall would be added for the utilities. This would create a thermal barrier amd a fire barrier. and would be

nice and warm and would befire proof. I’m still looking for ideas as to the top plate to  address the thermal probrem. maybe use

steel Truss plates to reduce heat transfer.

                                                                                                                                                        This is my two cents to this problem!

                                                                                                                                                                           Ted