Recycled Styrofoam Block Insulation

Introduction: Recycled Styrofoam Block Insulation

About: Neo-Renaissance Man

This instructable is to show you how to insulate your house using recycled Styrofoam glued into blocks.
Here's what you will need

Recycled Styrofoam foam peanuts or packing material made form Styrofoam ALOT of this stuff its easily found since its thrown away alot.

Great stuff expanding foam insulation, the large gap filler in the black can this can be bought at home improvement stores by the can at 4 dollars a can, or this stuff can be bought in 2 large separate cans called true green.

cardboard box


disposable gloves

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Step 1: Step One: Make Your Mold

 First you have to make a mold for your insulation brick, measure the space your going to fill with insulation.  Make sure to make the mold slightly lager then the space you want to fill.
  Then cut and form a cardboard box that size,  The box should fit securely into the space your going to fill.
  Then line your mold with some newspaper or other kind of paper.

Step 2: Step Two: Filling the Mold

 Now that you have your mold its time to fill it.
 First break apart your Styrofoam into no more then 1 inch chunks. and fill the bottom of the box with this. Then fill a bucket or box with enough chunks fill the rest of the mold.
   Now once you have the first inch layer of the bottom of the mold filled its time to use the great stuff to bind it all together.

Step 3: Step Three: Binding the Material

 Ok now you have a bucket of broken chunks of Styrofoam, and a inch layer of the stuff into the bottom of your mold. your ready for the binding material (great stuff).
  First USE GLOVES great stuff is super sticky and is hard to get off of anything!! Especially finger nails.
So now spray a layer of the great stuff onto the inch layer of the Styrofoam. (don't use the plastic tube that you attach to the can,  it will expand more this way)

 Now that you have a good layer on top of the first layer of Styrofoam now use yoru extra chunks of foam to make the secodn layer, then spray on a second layer of foam, this is your top coat and when smoothed out.
   Let this cure over night to harden.

Step 4: Step Four: Installing Your Insulation Block

 Now that your foam block is harden it looks like a giant rice crispy treat, You can take it out of the mold the paper should help it pop right out.
   And now just stuff it into the space in the ceiling your trying to fill. if you made the mold the right size then it should squeeze right into the space with out any other adhesive. other wise you can use a little more great stuff to cement it into place.

  Assuming you get the Styrofoam for free, and the great stuff for 4 dollars a can this insulation costs 1 dollar a board foot
a board foot being 1 foot by one foot by 2 inches thick. The block you see is 1 foot by 2 feet by 6 inches. i used one can per block.

THANKS FOR READING THIS AND IF YOU HAVE ANY STYROFOAM YOU WANT TO DONATE TO MY INSULATION PROJECT I COULD REALLY USE IT!! email me at i will pay for the shipping and handling for the foam or packing material but cant offer any money beyond it.


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    8 Discussions


    1 year ago on Step 1

    ive heard of grinding it into even smaller pieces and 3 parts styro "dust" 1 part cement mx then add water to make bricks. havent tried it yet but seemed easy enough and would save $$on the cans you have to buy.


    Question 1 year ago on Introduction

    If my pieces are large enough to cut and fit in layers where I need them do I really have to break it all apart and make blocks with the can's of spray foam?

    Reuse Portland
    Reuse Portland

    8 years ago on Step 4

    Be sure and spray great stuff between the blocks once they are up to block drafts. Also, have you tested how one of these things burns? Great stuff doesn't really burn but styo will. Future inspectors will not like this.


    8 years ago on Introduction

    Why not just save the four dollars each time you have it and then eventually you have enough to do the real spray foam! And what about the cost to the environment with all the propellents in the individual cans?


    8 years ago on Introduction

    I'd thought of doing this sort of thing, and I got worried that "packing" styrofoam might lack the sort of flame retardants that might be considered mandatory when using foam as a home insulation material. If you've seen styrofoam burn, you might be worried too...

    You can frequently find free styrofoam in great big blocks from companies that install big bulky items, like hottubs. They like to get rid of it because garbage disposal is pretty much charged for by volume, and styrofoam really sucks...
    Also large-screen TV vendors, and medical facilities (vaccines get shipped in disposable styrofoam coolers.) This sort of thing used to show up on "Industrial reuse" sites a lot, but lately they've been pretty empty :-(


    Reply 8 years ago on Introduction

    im aware of the fact that packing foam is not very safe in case of fire, but the great stuff does have a fire rating and will kinda act as a flame retardant.
    I am more worried about lowering my heating oil bill then my house burning down.
    but thanks for the tip for looking for foam ;)


    8 years ago on Introduction

    Great idea for recycling the foam.
    Good proof of concept.
    Needs refining before you put it into production on the farm.

    not sure how cost effective that is gonna be on a larger scale... the stuff-in-a-can is ALWAYS more expensive.

    This Old House has done a number of spray-foam insulation jobs, over the years.
    I think that may be a MUCH better way to go.

    Here's where the ideas merge into a better option.
    Tack flat blocks of your recycled foam to the wall voids, where you plan to insulate.
    leaving a 1" gap around all the blocks.
    Now, rent a foam sprayer(or get chummy with the local insulation guys :-)
    Use the spray foam to fill the gaps and topcoat the Styrofoam.
    The spray on stuff will not only glue everything into one homogeneous mass... the top coat will also act as a sealant (think vapour barrier, for that cavity).

    I think this would work MUCH better, unless you plan on building a foam-block structure on the farm, and then using a plaster/papercrete/adobe coating on top.
    In that case, certainly go with the block concept. But again, for the cost of 3-4 cans of spray foam, you could get a couple of POUNDS of 2-part Urethane Pour Foam. Fill the form with scrap, pour the mixed 2-part in, and let it fill the voids, and glue everything together.

    P.S. start stockpiling the foam and forms now.
    once you get rolling, you'll probably be producing 20-30 blocks in an hour.
    with help breaking up the foam... probably double that.
    with help mixing the 2-part...maybe up to a block a min?
    I can see pre-breaking the foam into large garbage bags.
    preping the forms.
    then blockmaking day = Fill boxes with loose foam(30 seconds per box?), mix 2-part, and pour...moving on to next box, once first has it's fill of foam(expands like crazy, so it won't take much), then off for a sandwich and soda, while the foam cures.
    80% of your processing time will be un-moulding the bricks.


    Reply 8 years ago on Introduction

    This is in a ceiling and i want to fill a space 6 inches thick so "tacking in" a piece doesn't really work of foam that yes as i mention you can use the spray in foam but as of right now i dont have the money for it, buying it at 4 dollars a can at ace hardware is more with in my budget then the 300-600 dollars for the two part spray in foam.
    ALSO i dont have all of the foam i need at one time i collect it in small amounts so if i had all the foam i needed yes this would work, but i dont. so i am doing it one brick at a time. with what foam i can collect.

    but yes if you had all the foam you needed and were doing walls this would work.
    i expect this to take me more then a year.