Vertical metal siding support over 8" rockwool - GreenBuildingAdvisor

Vertical metal siding support over 8″ rockwool Northwinds | Posted in Green Building Techniques on March 22, 2026 01:33pm Hello,I am beginning construction on a new home this spring. Most of my plans are in place but I just realized that the steel board and batten siding I plan to use, is designed to be fully supported at the bottom of each section and the clips that hold it to the wall leave it floating. I have engineered plans for ISO clips that attach horizontal metal girts (every 4ft) over my 8″ of exterior rockwool insulation to hold this weight. This siding though, requires all weight supported at the bottom where it would rest on a drip flashing.I have asked the supplier if they have any recommendations but being unusually thick exterior insulation I’m not sure I will get much of an answer back. I want to consider all options before deciding on one.I would also like to have a solution in mind before I ask my engineer to figure it out, as they likely haven’t dealt with this before. Especially considering they didn’t already spec the supports based on the siding I specified. In my mind the most likely way to proceed is with 12-16″ spaced ISO clips (over the rim boards) instead of 32″ spacing like elsewhere. With a heavier girt along the bottom of each run of vertical siding that supports the drip flashing which returns to the sheathing.We are also considering trying to do some areas in a stucco finish, or something else different, to break up the board and batten.I’m ...