There will be 2 types of insulation – both at 4″ for the perimeter walls. Interior walls will only have the second insulation. This does not count for the attic which requires a minimum of R-49. Therefore 7″ of spray foam insulation will be required in the attic.
The first insulation will be closed cell spray foam insulation. This insulation will provide an R-28. This goes a long way to meeting a higher R-Value standards. Because removing the insulation will require a bit of work and time, the infrastucural lines that might need replacing will not be installed in this insulation. This will include plumbing, electrical, and communications. Cent-Vac, and HVAC can have spray foam insulation surrounding the infrastructure. Spray foam insulation also has an added bonus of being a thermal break which keeps the cold from transferring to the warm side, and therefore prevent condensation.
The second insulation will be fiberglass insulation. This insulation is chosen to provide for a means of replacing, or repairing infrastructural lines such as electrical, or networking. There will be a manual created for the building, and will show where all of the lines runs from – therefore making it easier to repair. The repair person will just cut out the space they need, remove any insulation, and do the work. If spray foam insulation was to be used, it would require a lot more work such as chiseling the foam out, and then respraying when the work is done adding time, effort, and money to the repair project. Fiberglass insulation will be an R-14 which added to the 28 will be 42.