jeff5295
Well-known member
Just trying to get some info/advice. I'm looking to add some insualtion under my roof. Already have about 2" of closed cell spray foam (but looks to be a little less than 2"). Planning to nail 4x8 sheets of insulation boards to the underside of the roof purlins (open truss, not a flat ceiling).
I found a guy selling used 1" "ISO" foam boards so I went to Menards to compare new prices.
They have Owens Corning pink Extruded poly and also a white Expanded poly (similar to a styrofoam coffe cup).
The Extruded has a higher R value per inch, but the Expanded is substantially cheaper when comapring R values.
Obviously the pink is a denser, smoother finished inuslation.
I'm sure the pink would hold up better to impacts and abrasion, but this will be on a ceiling and it's way too high to be hit by anything so damage is not a concern. I will probably be covering either of these with white ribbed steel at some point to finish and protect the foam.
The pink is almost 50% more expensive, but has only 20% more R value than white (when comparing equal thicknesses). Seems like the white is the better deal. I would need to use thicker boards to achieve the same R, but would still cost less and I'd be looking at white instead of pink on the ceiling until I can afford the steel.
Still waiting to get a price on the used board, but thought I'd check other options for comparison.
Anyone know of any drawbacks to using the white Expanded poly on a ceiling instead of Extruded poly?
I found a guy selling used 1" "ISO" foam boards so I went to Menards to compare new prices.
They have Owens Corning pink Extruded poly and also a white Expanded poly (similar to a styrofoam coffe cup).
The Extruded has a higher R value per inch, but the Expanded is substantially cheaper when comapring R values.
Obviously the pink is a denser, smoother finished inuslation.
I'm sure the pink would hold up better to impacts and abrasion, but this will be on a ceiling and it's way too high to be hit by anything so damage is not a concern. I will probably be covering either of these with white ribbed steel at some point to finish and protect the foam.
The pink is almost 50% more expensive, but has only 20% more R value than white (when comparing equal thicknesses). Seems like the white is the better deal. I would need to use thicker boards to achieve the same R, but would still cost less and I'd be looking at white instead of pink on the ceiling until I can afford the steel.
Still waiting to get a price on the used board, but thought I'd check other options for comparison.
Anyone know of any drawbacks to using the white Expanded poly on a ceiling instead of Extruded poly?