just wondering what everyone would recommend ?
i live in the north jersey area and have a small crawl space 24x 28 about 40’high. home does not have any exterior ridgid board and i considering putting ridgid foam sheets on the inside of the foundation ( crawl space walls ) and cutting ridgid foam to fit tight into the box beam between the joists. Does anyone see anything wrong with this ? not sure what the relative humidty is but i dont see any signs of mold and i am also concerned about mold becoming a problem because of this. i know i seen an article in fhb about crawl spaces does anyone know what issue it was ?? biggest reason for the ridgid insulation is because of the moisture and the the mice
Edited 5/2/2008 4:50 pm ET by woody18428
Replies
The very best insulation for these types of spaces is foam but it is very costly. The reason it is superior is because it absolutely seals all airflow and moisture transfer.
http://www.airtightinsulation.com
The next best thing for what you want is a variation of what you mention doing. Ridgid foam insulation cut between the joists, but loosely, say 1/8-1/4" space all around, suspend the pieces with the insulation push wires or small nails. Then foam the cracks with expanding foam. I've done this many times in crawl spaces and it's much more effective than fiberglass, and it keeps the critters well at bay.
Is your crawl space vented with a cross flow? If not it should be. Is it dirt, or is there a rat slab?
Nothing wrong with what you want to do.
Don't you have to cover the exposed foam boards with some kind of fire-rated covering? Maybe I'm wrong but I think this is true..... something like drywall or scatter-shot gypsum or cementous material.
Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?
They have rigid foam that has the proper rating for exposure in a CS. You just have to make sure you get the right product. If you really want to know what the product is, (or at least 1 product) I could probably find out...
It's a good question and one I asked an inspector not too long ago. He said if it was a crawlspace on a slab it was fine. That's just one inspector's opinion though.
Well.... if you close off the CS perimeter, you have to provide an air source from somewhere else. BTW - what is on the floor of the CS? Also, putting foam on 40' high walls in a CS is gonna use a whole paycheck... no mater who you are.... OK - maybe not for Bill Gates...