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Foam board for duct work

byoung0454's picture

I am in the process of build a small weekend home, I am getting close to doing the  HVAC system. I was told by a HVAC installer that I could foil backed foam board for the duct system, he told me he has used if many times and was easy to install with the use foil duct tape. Now to me this dose not seam like a good idea, I am concerned about the pressure in the system. So has anybody ever seen of heard of doing this.

(post #110964, reply #1 of 38)

All the time. Get the installation manuel, proper tools and go for it...

 


                                      Here fishy fishy....

"Some days it's just not worth chewing through the restraints"

(post #110964, reply #2 of 38)

IMERC is right.


The guy wasn't talking about 4x8 sheets of foam board. He was refering to a product called Duct Board. It is designed for HVAC duct installation. Comaes in various sizes, pre scored, so you just fold it together and tape the seams.


Go for it.


Dave

(post #110964, reply #3 of 38)

Do you have a manufacturer and web site for this product.

(post #110964, reply #5 of 38)

no he said it was the same stuff you on the exterior of you house

(post #110964, reply #8 of 38)

Duh... Foam board...


Even with the reinforced poly filmed or foil on both sides it's a dissater waiting too happen. The foam board begins to break down to the point of total disignagration to the point of no more duct and all those little foam balls are are in everything... Now foam panels over metal ducting works. Glass insulation on the inside metal ducting of breaks down over time to the point that all you have left is metal duct. 




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                                          Here fishy fishy....

    "Some days it's just not worth chewing through the restraints"

    (post #110964, reply #9 of 38)

    "The foam board begins to break down to the point of total disignagration to the point of no more duct and all those little foam balls are are in everything.."


    IMERC,


    If the product were that bad, why do they sell it for use as exterior insulation?  The ducts I fabbed up eight years ago (out of foil faced isocy.) appear to be in perfect shape.....other than a little dust. 


    Jon

    (post #110964, reply #10 of 38)

    As a main duct trunk the forced air tears it up, friction and resonation I suspect. At turns or diverters and higher pressure points it's worse. It doesn't seem to wear well.

     


                                          Here fishy fishy....

    "Some days it's just not worth chewing through the restraints"

    (post #110964, reply #12 of 38)

    Thats art supply foam board Einstien..can't use it for ducks.


    A model of a duck OK..but not duckboard..


     




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    (post #110964, reply #4 of 38)

    "I was told by a HVAC installer that I could foil backed foam board for the duct system,"


    Byoung.


    Why do you not want to use metal ductwork?  Also, I have fabbed up ductwork out of foil-faced foam for a few "unique" situations.  I does work.


    Jon

    (post #110964, reply #6 of 38)

    I have no objections to using metal duct work he just suggested it because it has to be insulated because it going in the attic of the house

    (post #110964, reply #7 of 38)

    "I have no objections to using metal duct work he just suggested it because it has to be insulated because it going in the attic of the house"


    Byoung,


    OK, I see what you are trying to do.  Be aware foamboard ductwork is pretty fragile, and I have no clue as to the code compliance, but it works quite well in the VERY limited places I've used it, That being creating vents out the kick plates of cabinetry.


    Here's how I did it. Rip up on a tablesaw 3/4" foil-faced polyisocanurate insulation boards to the appropriate sizes (you could probably use a knife too). Fab them into ducts by gluing them with RVT silicone caulk, and tape the corners LENGTHWISE with FOIL tape, NOT duct tape.  Duct tape is not for use on ducts. Do this in half sections first, then put the two half-sections together forming the duct.


    Jon


    Edited 3/11/2004 11:07 am ET by WorkshopJon

    (post #110964, reply #11 of 38)

    Buy a cheap steel blade to do this.  It will dull the crap out of a good carbide blade fast.


    remodeler

    (post #110964, reply #13 of 38)

    Where are you located? I have TONS of fiberglass DB with foil and scrim..you can have all ya want..central KY here.


     




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    Repairs, Remodeling, Restorations. 


     


     

    www.richmondrenovationsandrestoration.com  

    (post #110964, reply #14 of 38)

    I am in Missouri

    (post #110964, reply #15 of 38)

    not far..how much ya need? I got approx. 3' x4' pcs..all 1 inch thick..some 16'' x4'  some 22'' x 4'..good stuff brand new..


    FREE..


     




    Spheramid Enterprises Architectural Woodworks


    Repairs, Remodeling, Restorations. 


     


     

    www.richmondrenovationsandrestoration.com  

    (post #110964, reply #16 of 38)

    i woulds say about 25 of the 3x4

    (post #110964, reply #17 of 38)

    That's a deal. Make it 50 and you're covered.....

     


                                          Here fishy fishy....

    "Some days it's just not worth chewing through the restraints"

    (post #110964, reply #18 of 38)

    that will work for me

    (post #110964, reply #19 of 38)

    Since you saved a BUNCH of $$$ now go get the notch and shiplap slicers, there's 3 that you need and the clinching stapler. DON'T FORGET the duculator or the rolls of reinforced foil tape.


    Check with an area supplier while you are picking up all your STUFF and get the how to manual...


    Have fun...Hehehehehehehehehehehehehehe.......



     


                                          Here fishy fishy....


    Edited 3/11/2004 8:36 pm ET by IMERC

    "Some days it's just not worth chewing through the restraints"

    (post #110964, reply #20 of 38)

    when would be a good time to come get it?

    (post #110964, reply #21 of 38)

    it has the ship lap already.., you will need the tape..my cost is around 5 bucks for 350ft roll.  what is the overall sixe duct ya need? the shiplap will give ya 4' lengths..by? what width and height?..you can miter the edges easy for a box duct..3'board with cutting equal sides gives a 9x9 outside duct..gonna work thata way?..or ??


     




    Spheramid Enterprises Architectural Woodworks


    Repairs, Remodeling, Restorations. 


     


     

    www.richmondrenovationsandrestoration.com  

    (post #110964, reply #23 of 38)

    Using 2 pieces will give ya a 12x24x48 or 3 pieces will give ya an 18x36x48 sortta. A tad more realistic for trunks....

     


                                          Here fishy fishy....

    "Some days it's just not worth chewing through the restraints"

    (post #110964, reply #25 of 38)

    now tell me the lbs. per sq. ft...see if he'll pay for UPS. I ain't THAT generous..I do know that 5 @ 3x4 is a handfull to carry in the wind..especially the wind INSIDE the house cuz all the (*^%$#%^  CHINKING is gone..


     




    Spheramid Enterprises Architectural Woodworks


    Repairs, Remodeling, Restorations. 


     


     

    www.richmondrenovationsandrestoration.com  

    (post #110964, reply #27 of 38)

    I will pay for shipping I have a UPS account.

    (post #110964, reply #32 of 38)

    How you two link up is your problem... I'm gonna go back to snooze....

     


                                          Here fishy fishy....

    "Some days it's just not worth chewing through the restraints"

    (post #110964, reply #33 of 38)

    me too...I gotta hang rock in the AM...finally.  A ductulater..what else ya got cookin there?..


     




    Spheramid Enterprises Architectural Woodworks


    Repairs, Remodeling, Restorations. 


     


     

    www.richmondrenovationsandrestoration.com  

    (post #110964, reply #34 of 38)

    All that duct was a SWAG with out having the whole word and it's "latOr" BTW. Have him come and get the sheets, any cracked or broken sheets are about useless. WTB that UPS won't have his best intrest in mind either. He may get just so much junk delivered. If he plans on enough material to make a 12x36x?? trunk, a couple of feeder branch stubbs and adds a fudge factor.... Good to go.  

     


                                          Here fishy fishy....

    "Some days it's just not worth chewing through the restraints"

    (post #110964, reply #35 of 38)

    he's drivin out end o month to p-u...I should MOST of mine put up by then...yeah, UPS would trash it..gonna start brokering all the free stuff I get..this Co. where I get it throws out 4x4x4 pallets every 3 days of it random widths all 4' long.


    I can get the foiltape 4 bucks a roll..but I just been using packing tape for my install..no ducks anywhere in my house. Hell, I got no heat anywhere yet.


     




    Spheramid Enterprises Architectural Woodworks


    Repairs, Remodeling, Restorations. 


     


     

    www.richmondrenovationsandrestoration.com  

    (post #110964, reply #24 of 38)

    I think the 12x24 is the way to go for the main trunk. Thats what  I was told by a HVAC guy. The main trunk will be 32' long.

    (post #110964, reply #28 of 38)

    that works out to 16...25 ought to do fine..they may not be right at 36" so I would say at worst case 35 will work..( I seem to remember a lot at 32"..) and there is always more..how do we get it to ya?....Lexington here..4 hrs maybe?


     




    Spheramid Enterprises Architectural Woodworks


    Repairs, Remodeling, Restorations. 


     


     

    www.richmondrenovationsandrestoration.com