Whereas the outside of the house has gone blue, the inside is going a fetching green colour. The ceilings and walls are being covered in SmartPly VarPairTight: an OSB board which comes with an airtight layer already attached. 
The blue tape seals the cracks between the boards to make it completely airtight.
Once everything has been boarded the Warmcell people can start filling the gaps between the Ibeam joists with insulation.