Can generic silicone be used to seal a roof channel seam against a water leak?

[RMcG]

QUESTION: Can a more generic form of silicone rubber sealant, such as GE Advanced Silicone for Window & Door projects, see Amazon link (https://www.amazon.com/GE-GE500-Silicone-Window-Squeeze/dp/B000M2UPAG/ref=sr_1_4?crid=28AUQV6TVDXE1&dchild=1&keywords=ge+advanced+silicone+window+%26+door+seal ant%2C+2.8+oz+tube&qid=1620794634&sprefix=ge+advanced+silicone+window%2Caps%2C252&sr=8-4) be effectively used to seal a roof channel seam. Picture of a short segment of a roof channel at the front of the car roof is attached (this is not my car, it is taken from another post on this forum). According to the package, this GE product has a service temperature from - 60 degrees F to + 400 degrees F and it is often used on roofs (they probably mean house roofs). The product is supposed to be shrink and crack proof. And I think it is UV light proof as well based on reading

There is a similar clear 3M silicone sealant that is specifically made for auto bodies, see link (https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Clear-Super-Silicone-Seal/?N=5002385+8709313+8710891+8711413+8716717+3293242 013&rt=rud), but this formulation seems to be for professional auto body shops. And I cannot find it in auto parts stores.

I plan to use the sealant on the base of the roof channel, then use the sealant to adhere the rubber strip to the base of the channel and then run a bead of the sealant along both sides of the rubber strip and smooth the bead with a gloved finger so there is an impervious water barrier between each edge of the channel and the rubber strip.

QUESTION: Does this sound like an effective strategy? Any other comments will be welcomed.

Thanks,

R.




61721

[RMcG]

I am going to reply to my own query above. I already used the strategy described above a few months ago with GE silicone rubber sealant for Kitchen & Bath see link (https://www.amazon.com/GE-GE286-Silicone-Kitchen-Squeeze/dp/B000BQWKCY/ref=sr_1_13?crid=LOYTSAW8B12H&dchild=1&keywords=ge+silicone&qid=1621023904&s=hi&sprefix=ge+silis%2Ctools%2C286&sr=1-13). It was put on when the temperature was between 50 and 35 degrees F. According this link (https://www.adhesives.org/adhesives-sealants/adhesives-sealants-overview/adhesive-technologies/chemically-curing/two-component-(2-c)/silicone-adhesives) from adhesives.org, that is probably OK for a silicone based adhesive, since the temperatures required for cure are 40 to 100 degrees F with some humidity. The seal looks good and there has been no cracking in the past several months. Silicone rubber sealant is UV and temperature resistant. The only difference between the GE formulation I used and the GE formulation for Windows & Doors is the addition of a biocide, apparently to kill mold in a bathroom or kitchen. 3M advertises their automotive sealant to be vibration resistant as well, so there may be a difference there that is significant for autos. On the other hand, house roofs and windows and doors and seals in kitchens and baths experience vibrations as well. I called GE and they just told me that they did not advertise this particular sealant for autos.

I will try to update this post to state the success or failure of this strategy.

Addendum: I looked at the 2 week period of time in late January when I think I performed the technique/strategy in my first post above; the average high was about 49 degrees and the average low was 38 degrees. The lows here usually only last about 2 hours, so I think that if the surface of the car was less than 40 degrees F it was likely only below 40 degrees for a short period of time -- it takes time for the car surface to cool down after it has been warmer for most of the day. So the car surface was probably less than 40 degrees F for probably less than 2 hours at a time, if that. And it would not have been less than 40 by much.

Thanks,

R.

[Grindstone]

Thanks for the update. Hatch seal leaks are pretty common.

[bronsin]

Is your roof leaking?

[ralley77@?!]

If water is sneaking inside around the windshield go to a windshield replacement shop and get their advice.

[matthewbrown]

Hatch seal leaks are very common in these days and you can easily get these on amazon.

[IndestructibleYaris]

You're definitely not having a leak that silicone can fix, you were either just missing the drip rail molding or your windshield frame has rusted, either way fix it right, don't just slap silicone on it