Budget-Friendly Alternative Caulk
user-5538665
| Posted in Green Products and Materials on
Does anyone have a recommended, less expensive alternative to Pro Clima Contega HF. Current prices on Contega HF are $1.07 an ounce.
I will be using it to air seal Intello Plus to interior wood.
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Replies
HI Drew -
I am not sure why you would select a premium membrane product like Intello Plus and then not use the other components designed for use with the premium membrane. All sealants should be tuned for material compatibility and that is the advantage of a system of products/components in an assembly.
I am sure that you could find a different sealant that is compatible with the Intello but you would either need to get that confirmation from a technical source from the sealant manufacturer or do some field testing for compatibility on your own. And having done some of that sort of testing, it's the compatibility over time so put your field test through some temperature and moisture content cycles to stress the bonds to substrates.
Peter
Aside from the specific compatibility with Intello, I've found that Contega HF is great stuff to use for lots of general sealing applications, particularly where the traditional choice is acoustic sealant, which is toxic, smelly, and messy. If anyone knows of a good low-toxic-vapor sealant that is cheaper than Contega HF, I would be interested to know about it. There are other caulks promoted as being relatively chemically safe, but I don't think they are intended to stay flexible to anywhere near the degree that Contega HF is.
Contega HF is not as low VOC as some, but the VOC is ethanol. Ethanol doses have to be much larger than you get from caulking to be dangerous.
Sashco Big-Stretch at about $0.60 an ounce seems worth considering.
http://www.sashco.com/products/big-stretch/
@charlie, Good to hear you like Contega HF. Where have you purchased it?
@peter, Thank you for the perspective. Why you ask... I will offer an analogy. When buying an Apple computer, I could order it with the memory I want from them. Its guaranteed to be compatible. However, for much less, and with equal performance, I buy third party memory. Sometimes you do not have to stick with a system do get equal or at least imperceptibly different results.
I've purchased Contega HF from 475, and it was expensive but, I think, worth it.
It has 10-15% ethanol, vs. big stretch's 5-10% petroleum distillates. I prefer to breath ethanol, but how much of it you breath depends on the ventilation where you use it, etc. I don't see any other ingredients in Big Stretch that would concern me, but I might be missing something.
Regarding compatibility, I tested Intello with PL Acousti-Seal as well as Green Glue Sealant (not the Compound). Both bond well to the fabric backing of the Intello and both remain reasonably flexible. The GG Sealant also sticks well to the smooth face of Intello. I have not yet tried Contiga HF.
The Green Glue Sealant is supposed to be "non-hazardous" and certainly doesn't smell offensive when using it, which cannot be said for the Acousti-Seal.
I get the impression that Contiga HF will stay flexible, a sort of pliable "rubbery" state and allow for movement. I did not test the Acousti-Seal or GG Sealant in thick beads, only pressed thin between the Intello and a wood stud with staples. Pressed thin, both had high shear strength but peeled without too much effort. The GG Sealant resisted peeling more than the Acousti-Seal.
I do plan to test Contiga HF in the same manner, I just haven't gotten around to it yet.
My preliminary thoughts are that the GG Sealant may be a contender for sealing the back of Intello to wood in areas where I don't see much risk of movement.
Contega HF is amazing stuff. Like other Pro Clima products, in North America it's only available from foursevenfive.com. It is on the expensive side but nothing else I've found matches its combination of low-VOC, permanently flexible, quite sticky, and with broad compatibility with other materials. You might spend $250 for enough to seal everything on your house. Or you could spend $150 and have a mix of smelly products that may or may not work well with Intello.
(I have no relationship to 475 or Pro Clima and regularly spec their competitors' products. But it's hard to beat Contega HF.)
Excellent point, Michael. If I were subscribing to the Pro Clima product line for my whole house requirements I certainly would plan to stick to their recommendations rather than try to save a few bucks on sealant. Why compromise the performance of those expensive top-tier sealing products? Doesn't make sense.
In my case, I was looking to do some extra sealing above and beyond the approach recommended by 475. My ideas would involve a lot of additional sealant, so the potential savings would be very worthwhile.
Lance,
I take Peter and Michael's points, but I also agree with you. You can play the "it's only an extra 20%" with almost anything you use on a build. On a typical new house that can add up to $80k.
I have a specific, and time sensitive question about Contega HF sealant from 475:
My modular house ‘boxes’ are schedule to be set early Thursday morning, and I would like to use the Contega HF in addition to the standard foam sill seal before they set the modules onto the foundation wall and framing (house is on a hill).
475 indicated "HF should be applied within minutes of contact to both surfaces for maximum adhesion. Once it is exposed to air it will start to set, though it will not dry out”, and their site indicates 1-2 days when used with membrane to sheathing connection.
On my site, It will be impossible to apply it a few minutes before a huge crane begins its maneuvers, and I’m wondering if anyone has applied it, and left it exposed until the next day before adhering the materials?
Thanks,
Based on my experience with it, there's no way I would lay down a bead of it and then expect it to permanently bond to anything the next day. It remains somewhat sticky over time, but not such that it would still seal, I don't think.
One thing to observe is that it changes color. It dispenses as a creamy green color and then cures into a bolder, but more translucent green color. That may be indicative of how much it has set up.
Could be useful to run a test.
Stuart,
Rather than sandwiching sealant under the modules, I would tape the exterior intersection between the concrete and wood. This has the added advantage of dealing with possible air-leakage between the bottom-plates and sheathing.
Once you see how embedded it is in the Intello, like their tape, I don't know why you would skimp. Go cheap somewhere else. Cheap light fixtures or something else. You get one chance to air seal correctly. I would not use anything else.