Great Stuff Foam used intead of end cap ? Dangerous ? Okay ?

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Great Stuff Foam used intead of end cap ? Dangerous ? Okay ?

Lele H.
Washington, DC · Member since 2017 · 4 posts · 0 votes


Hired contractor to remodel kitchen.

Needed vent pipe capped off .

He was supposed to cap off an open hvac pipe that is blowing hot air from the ceiling.

It used to lead to a heating vent in the old wall that was removed.

Instead of using foil duct tape, he sprayed "Great Stuff" foam INSIDE of the 8 inch in diameter active vent/pipe.

I told DH to turn off HVAC heating to avoid drywall dust. Sub didn't even mention turning anything off.

I have looked and looked online but can't find anyone using foam to seal off the entire end of an HVAC vent/pipe.

His excuse for not using the foil tape he had was that it would stick.

Anyone ever use Great Stuff to seal off an entire vent ?

It says it uses a highly flammable gas to expel it form the can and that Great Stuff itself is hugely flammable.
Should we be scared to turn the HVAC back on ?
He used ton in the hole ?
Is this really bad form to use that intead of an end cap ?    
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JD MartinBusiness Member
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Rock Star Extraordinaire · Northeast, TN · Member since 2015 · 10k+ posts · 16k+ votes
9y

I wouldn't be scared. Once the stuff dries it's not volatile. That doesn't mean it's not flammable, but it's not going to catch on fire from warm air from a heating system. But I wouldn't have used expanding foam to seal off a vent, either. Why didn't he just put a cap on the vent? They make caps with gaskets. 

If you had a picture it might make better sense.

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  • Roy N.Pro Member
    Rental Property Investor · Fredericton, New Brunswick · Member since 2013 · 7k+ posts · 4k+ votes
    9y

    Instead of what kind of end-cap? .... what is the application (plumbing, HVAC, siding, etc)?

    [OK ... just saw the embedded post].   Using expanding foam as an end-cap on a heating / vent run is a little unorthodox.  It's not likely dangerous - while Great stuff is flammable - the hot air in your duct line will not ignite it.

    What may happen is the foam will eventually loosen over time with the repeated expansion and contraction of the vent pipe and the seal will fail.  This will result in warm air being discharged in your wall/ceiling, which could cause problems.

    Why not install a proper 8" duct end-cap or, better yet, disconnect that branch where it comes off the trunk and cap it at that point.

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  • JD MartinBusiness Member
    Moderator
    Rock Star Extraordinaire · Northeast, TN · Member since 2015 · 10k+ posts · 16k+ votes
    9y

    I wouldn't be scared. Once the stuff dries it's not volatile. That doesn't mean it's not flammable, but it's not going to catch on fire from warm air from a heating system. But I wouldn't have used expanding foam to seal off a vent, either. Why didn't he just put a cap on the vent? They make caps with gaskets. 

    If you had a picture it might make better sense.

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  • Lele H.
    OP
    Washington, DC · Member since 2017 · 4 posts · 0 votes
    9y

    He covered it up with drywall before telling us what he had done. Probably will ask him to do it properly as it just seems crazy.

    Thanks for the fast replies !

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  • Mike Wood
    Developer · New Orleans, LA · Member since 2015 · 1k+ posts · 898 votes
    9y

    @Lele H. I am also perplexed on why he chose to do that.  The expanding foam is more expansive than other methods. I would not worry about it if it is sealed.  This stuff is used to seal houses, so it should be fine on the duct.  I dont think it will ever loosen or leak.

    Once dry, there is no concern about the product.

    Since it is drywalled in, are you sure its closed off? They crazy explanation would have me questioning.  You definitely do not want an open duct inside a wall, that will just be wasting money.

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  • Lele H.
    OP
    Washington, DC · Member since 2017 · 4 posts · 0 votes
    9y

    Starting to think this guy is cray cray. We explained to him that no he could NOT use a 120k BTU kerosene heater in a smallish 400 sq foot enclosed space. Its 55-60 degrees in here, but he wanted to speed up drywall drying.

    Gave him a new electric heater. Asked him to please remove his open canister of kerosene and kerosene heater and take away.

    Instead he snuck out the back and left the kerosene heater AGAINST the gas hot water heater[ kerosene heater turned off, of course] With kerosene still in it. Figured this out when I moved it away from the gas hot water heater.

    He also handled eco fiberglass by hand and told us its safe because it's ECO. Nope.

    Should I just complain to his boss , the contractor ?

    Already paid them 11k and starting to feel dumb.  

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  • Lele H.
    OP
    Washington, DC · Member since 2017 · 4 posts · 0 votes
    9y

    Today more madness from contractor sub.

    The sub came back, I know I should have barred him from doing so.

    But he had all his materials here.

    Another part of the remodel is to remove some cheap peel and stick vinyl tiles were over 70 year old asbestos tiles.

    I wandered into an insane scene a little while ago. Have you ever shook with rage ?

    Everyone involved was told the asbestos stays and will be encapsulated by self leveling concrete and hardwood. This is what the EPA.gov website said was best [pre Trump, don;t know if its still up there] and I agree.

    Yesterday I looked the sub square in the eye and went over with him that he was ONLY peeling off the vinyl from the asbestos tiles.

    He said oh yeah he used ot own a ServPro and a job like that would have cost 5k with his biz.

    So I took comfort that this blithering idiot at least understood NOT to remove the asbestos tiles.

    Long story short he took up the peel and stick just fine.

    And then he apparently went to town chipping and breaking up a bunch of the asbestos tiles.

    And scraping the asbestos mastic too.

    I took video and photos and am basically in shock.

    I am in Maryland am now figuring out what to do.

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  • Manolo D.
    Contractor · Los Angeles, CA · Member since 2015 · 4k+ posts · 1k+ votes
    9y
    Lele H. Asbestos... Ok, not that alarming right? Or so you think. I had just paid someone to remove 1500 sq ft of asbestos mastic on floor vinyl tile and/or carpet glue. Paid 30k for "properly" removing and disposing it, with all the testing and insulation, that is how alarming it is, if you don't "touch" it, it is fine, and peeling something is more than "touching", right now asbestos fibers might be circulating in your house, it will be like that and you might inhale it. That is, if you want to remove and dispose everything correctly.
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  • Luc Boiron
    Specialist · Toronto, Ontario · Member since 2016 · 564 posts · 425 votes
    9y

    @Lele H. I can't imagine it's your fault that he removed the asbestos - get his boss to make sure it is disposed of correctly, make it clear in writing that you had understood it was not to be disturbed, and it shouldn't be a problem.

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