polystyrene (styrofoam) as insulation

[Malibu surfer]

Hi all,
Had a quick question about Styrofoam boards as insulation. I have a friend who owns a hot tub shop and has a ton of 12"x 4-5 ft boards of 2 or 3 inch Styrofoam packaging boards they ship new hot tubs in. I know the R value is not the best, but my climate is pretty mellow here in S. Oregon/ N. California. Best part I can have them all for free.
Thinking of gluing them together and fitting/cutting them in my E150 hi top project.
Are these packaging boards safe? Curious what you all thought. Looking at it just from a safe breathing standpoint.. It will be behind luan sheets.
thanks.

 

[djkeev]

How worried are you about fire?
They won't cause a fire but they may kill you in a fire.

Dave

 

[Malibu surfer]

In most of our vans we have stuff that can kill us if a fire starts. I'm thinking carpet, bedding, cabinets and walls would go first.. I'm just trying to weigh out the free stuff over the pink or white board at say like Home Depot....

 

[highdesertranger]

Styrofoam is actually a good insulator. if you try to glue it you need to find a glue that is compatible with it. a lot of solvents eat Styrofoam. highdesertranger

 

[GypsyDogs]

If I was going to try to stick sheets of styro together, I'd probably use double stick tape. Just the thin sticky strip stuff, not the mega gorilla nonsense. especially if you are going to sheet over it with Luan. so you just want it to hold in place..

 

[Malibu surfer]

Styrofoam is actually a good insulator.  if you try to glue it you need to find a glue that is compatible with it.  a lot of solvents eat Styrofoam.  highdesertranger

thanks HDR. When I was younger (12) I tried to make a surfboard out of Styrofoam. I learned then that it does not like solvents of any type or poly resins for that matter haha

 

[sushidog]

My Aliner is constructed out of Styrofoam composite. It is an inch of foam with thin aluminum sheeting glued to the outside and 1/8' plywood covered with thin fiberglass on the inside. The construction is super light, well insulated (I think R-5), making a very rigid SIP (structural insulated panel.) If you used a spray glue to sandwich the foam between 2 thin hard layers (like plywood or Filon) it will increase the rigidity of the structure in addition to providing excellent insulation. My shower enclosure is made in this manner, as is my counter top and cabinets inside, making it super light yet strong.

Remember, as far as insulation goes, you can hold a cup of super hot, almost boiling coffee in a 1/8" thick Styrofoam cup. The disadvantage of foam is that if not glued or screwed firmly in place it will squeak while traveling down the road. This may or may not bother you, but it aggravates the heck out of me.

BTW, I've used this glue for Styrofoam in the past and it works great. https://www.amazon.com/3M-78-Polyst...coding=UTF8&psc=1&refRID=BZ4A8M2Q46Z46BXS4WN1

Chip

 

[DannyB1954]

I believe a primer paint called Glidden Gripper can be used as a glue. Just give it plenty of time to set up, (being between plastic may take longer to set).
http://www.therailwire.net/forum/index.php?topic=32025.0

 

[anewbiewannabe]

Great info here thanks.

Sounds like a great way to freecycle. It might work for those cabinets built out of foam board too. Lightweight and free construction materials? SCORE!!!

 

[TrainChaser]

Polystyrene has an R-value of 3.85 per inch; if you put 2" of it on the walls and ceiling, you're exceeding the rating of 1" of polyiso. And it doesn't absorb moisture. The little house people recommend it.

I don't know what kind of adhesive would be best to join it to metal, if that's what you're doing. Just don't use hot-glue: the hot-melt melts the foam, and the low-melt softens when the metal skin heats up.

 

[sushidog]

The pink, blue and green extruded polystyrene foam board has an R-value of 5 per inch of thickness. It's the cheaper white expanded polystyrene that has the lower R-value.

http://www.ehow.com/info_8561934_difference-pink-blue-foam-board.html

Here's a link that describes the differences between the various foam boards with prices:
http://owensupply.com/Docs/supplies_insulation.htm

Chip

 

[One Awesome Inch]

I've found that Gorilla Glue, in the industrial size tube, bonds polystyrene and metal well.