# drying wet xps foam boards



## kreator33 (Oct 7, 2017)

p.s. i ave acces to a room wit ventilation and heat,, my unused paint booth , or i can make a shelter outside, im in new brunswick canada, so i have until now till about april where i can dry them over the winter, i immagine drying would stop outside if the water freezes?


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## ClarenceBauer (Mar 4, 2005)

You most likely can not get all the water out maybe 80% take a new 1 ft. sq. and weigh it than do the same with the wet sq. Now take the wet sq. and put it in the oven with just the pilot lit and leave for 24 hrs. than weigh it again see what the difference is.


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## Bud9051 (Nov 11, 2015)

If you have xps, as far as I know it is closed cell extruded polystyrene and does not absorb water. If yours has absorbed water then I suspect it is polyisocyanurate which cautions against exposure to water. Being blue is a bit confusing because Dow xps is also blue.

Are the sheets marked in any way to tell you what they are?

Bud


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## kreator33 (Oct 7, 2017)

YES, they are dow chemicals, roofmate 2 inch extruded xps, i have read about their false claim that they dont absorb water, they test em submerged for 24 hours, but in real life, a few decades underground doesnt compare to 24 hours in a pool when new. some of the panels weigh like a feather, while others weigh a ton, you drop one on the ground, it shatters , feels dry to the toutch, but when you break it open, it is saturated with water, like a very thight sponge,,, being non absorbant, also makes em reaaaaaly hard to dry i guess, once water gets in,i have read somewhere that it is impossible to dry, but impossible aint usually part of my vocabulary, if it got in, there must be a way to get it out


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## NotyeruncleBob (Mar 9, 2017)

Sort the wet ones from the dry ones and return the wet ones from whence they came.


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## kreator33 (Oct 7, 2017)

not an option, if it would have been, i wouldnt be here. got them for dirt cheap.


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## NotyeruncleBob (Mar 9, 2017)

kreator33 said:


> not an option, if it would have been, i wouldnt be here. got them for dirt cheap.


So is it still dirt cheap if you have to throw out all the wet ones?


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## NOCAP (May 3, 2019)

Has anyone found a way to dry these 100lbs. plus sheets of XPS board that are soaked in water. My guess would be they need to bake for extended period on low temp maybe 150 deg Fahrenheit but I’m not sure. Anyone succeed or even try? Clearly XPS Foam board insulation holds water but can it be removed or ever dry????


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## Nealtw (Jun 22, 2017)

I found this. 



http://forums.sailinganarchy.com/index.php?/topic/177080-drying-out-foam-core/






I did something similar once. I drilled holes in about a 12' grid. Rather than one at a time, I did the whole lot at once using bagging film and a flow media something like this http://www.fibreglast.com/product/4925/Vacuum_Bagging_Vacuum_Infusion

Take several days to extract the water since it didn't flow out, more like boiled or vapourized out. I would say the core was more damp than waterlogged prior to vacuuming so the dump tank only had only about maybe 1/2 cup of water in it from about a 25 sq ft area. Most of the water probably came from the kerfs. Pretty tough to get water out of the foam I think. 

In hindsight, I would say it was a waste of time - and I had no expectations of removing 40 lbs of water, just tried to dry the core which it did, but wouldn't do it again.


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## Yodaman (Mar 9, 2015)

I would stack them up like green lumber with stickers between, in a enclosed room, and run a dehumidifier continuous until dry. If no room available make a tent using plastic.


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## Nealtw (Jun 22, 2017)

I wonder if there is still an R value when it is wet, there might be user uses for it.


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