Right - Closed-cell spray foam insulation fills the wall cavities of the exterior walls in this home retrofit | Building America Solution Center
![Spray Foam Insulation Applied over the Siding of Existing Exterior Walls | Building America Solution Center Spray Foam Insulation Applied over the Siding of Existing Exterior Walls | Building America Solution Center](https://basc.pnnl.gov/sites/default/files/images/TE7228_ExtSprayFoamRetro-S_IBACOS_12-17-14.jpg)
Spray Foam Insulation Applied over the Siding of Existing Exterior Walls | Building America Solution Center
![Spray Foam Insulation Applied over the Siding of Existing Exterior Walls | Building America Solution Center Spray Foam Insulation Applied over the Siding of Existing Exterior Walls | Building America Solution Center](https://basc.pnnl.gov/sites/default/files/TE7228_ExtSprayFoamRetro-7_IBACOS_12-17-14.jpg)