Foam first or last in cold enclosed porch floor?
I have seen this question answered many ways while searching online, so I thought I would pose it here. I know there is another thread on this topic, but it seemed worth posting again.
When insulating an enclosed porch that is not climate controlled, should the layering be: pink foam board affixed to the floor underside, fiberglass batts, plywood for vermin control?
Here’s the application:
Home is built 1923 in the Chicago area. Screened porch with heated room above (sometimes called a “tandem room” here), two walls adjacent to main climate controlled home. Porch has double pane windows and a storm door, but it is and will remain unheated or uncooled. The porch floor is about 4 feet above grade and not enclosed.
My goals for insulating at all is, I feel, pretty realistic: 1) To get an extra few weeks use in the spring and fall. 2) Provide a more stable temperature zone/buffer to moderate or slow loss from and incursion to the main house (if that’s even possible/realistic).
My number one concern here is creating a moisture issue by layering incorrectly.
Thanks in advance!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part