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Community and Q&A

Tremco acoustical sealant vs. Tremco TREMPRO JS-773

Dillon Vautrin | Posted in Green Products and Materials on

Does anyone know the difference between the two? I know the Tremco accoustical sealant is the black death that is known to have properties which make it good for air sealing. The Tremco TREMPRO JS-773 is quite a bit cheaper and is described to be non-skinning and non drying like the acoustical sealant, but I don’t really hear of anyone using it. The TREMPRO JS-773 also seems more readily available online. Would the TREMPRO JS-773 be suitable for sealing the sill plate if used in conjunction with an EPDM gasket?

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  1. User avatar GBA Editor
    Martin Holladay | | #1

    I suggest that you telephone Tremco and ask for customer service or technical help. I'm sure that one of their reps can answer your question.

    3735 Green Rd.
    Beachwood, OH 44122-8067

  2. Charlie Sullivan | | #2

    This isn't what you asked, and you are probably aware of it, but tremco acoustical sealant smells nasty, and continues to smell at least somewhat bad for months. Its ingredient list includes residual oil--the bottom of the barrel leftovers after a refining process. That means it's an unknown mix of hydrocarbons, some of which are almost surely harmful to the installers or the residents of the well sealed house. What I don't know is whether the concentration of the harmful components is significant. When a product includes a specific VOC ingredient, you can asses risk to workers and use ventilation and or respirators appropriately; with a mix of unknown sludge, it is harder to know what is appropriate.

    I am not familiar with Trempro js773, so I don't know whether it has the same problem. I like contega hf as a less nasty alternative that works well, but it's more expensive, not less.

  3. Dillon Vautrin | | #3

    According to a representative they are two very similar products that Tremco distributes through two different distribution channels. I didn't really get much more out of them than that. But it sounds like they can be used interchangeably for this application.

  4. Charlie Sullivan | | #4

    The MSDS sheets for the two show that they are nearly identical They both have the same solvent and residual oil content. But the Trempro has titanium dioxide instead of carbon black. And it's described as off white vs. the acoustical sealant which is black. So it may be mostly a question of which color stains you want on your pants. The datasheets do, however, specify different solvents for cleanup for the two, which doesn't make sense to me.

    Note that neither one has the "reduced VOC" or "improved IAQ" box checked on their list of features on the Tremco web site.

  5. Dillon Vautrin | | #5

    I plan on using this for the sill plate which will be outside during construction. My home will be a lot of self build so I shouldn't be in it for 6 months or more so I am not terribly concerned with VOC at this point in the game though I do realize all off gassing does not occur in just the first six months. Thanks for the good info and for Martin pointing out who I should have asked in the first place.

  6. Malcolm Taylor | | #6

    As Charlie pointed out you are going to end up with some Tremco on yourself sooner or later. That's inevitable. What I do try and avoid when the sequencing of construction means it will go on early is getting the Tremco covered in sawdust and other debris from the site during the remaining construction. If you are laying a bead that will be exposed, it's worth bedding a thin piece of poly or building paper in it to keep it clean.

  7. KauaiBound | | #7

    I compared the two Tremco products (Tremco Acoustic/Curtainwall Sealant and TremPro JS-773 Sealant). Other than the color (and the price), they seem to be very similar, although not identical. The TremPro seems a bit less smelly, but has similar gooey/stringy non-skinning consistency as the Black Death and comes in a soft grey color. S&S Sales sells it for $6.34+ tax for a 20 oz sausage, which is significantly cheaper than what I've been able to source the Acoustic.

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