Roof Sealants – Further Info

12-03-2010, 08:45 AM

During a recent light rain, I noticed water dripping from the ceiling under where the antenna is attached to the roof. After reading some of the posts here about re-caulking leaks, I went shopping online and here is some further info on what has already been posted. Hopefully, it might be helpful to others who are just starting to explore a leak problem.

*** I found posts that recommended 3M 4000 UV Polyether Adhesive Sealant which currently can be found online at westmarine dot com for $15.99 per 10oz cartridge and $12.99 per 3oz tube. Here is West’s description of the product:

“4000 UV Polyether Adhesive Sealant@Body Text:Resistant to weathering, salt water and stresses caused by joint movement. White, non-yellowing formula is ideal for above and below waterline applications where aesthetic appeal is a priority. Seals between mechanically fastened joints on wood, fiberglass, metal and most plastics. Applications include sealing deck to hull joints, thru-hull fittings, window and door frames,etc. It is also paintable. Highly recommended for ABS, Lexan and other plastics.
• Formulation: One-part polyether adhesive/sealant
• Recommended Usage: Fiberglass, wood, metal, some plastics
• Cure Time: Tack free: 2 hrs; complete cure: 24 hrs
• Clean Up: Mineral spirits or kerosene
• Removal: Mechanical removal
• Tensile strength: 300psi”

*** Note the use of kerosene (and Mineral spirits) as a possible clean up material. I haven’t seen this possibility mentioned in previous posts.

*** I also found posts that recommended C-10 Flow Seal Self Leveling Caulk which currently can be found online at Amazon.com (*** Note: C-10 is made by Dyco which has been mentioned in some posts as available in trailer parts stores at a much higher price than Amazon.) and is priced by Amazon at $6.20 per cartridge for the white, ivory and for the grey. Product description is:

Perfect for use on horizontal surfaces, such as roofs of recreational vehicles, mobile homes, metal buildings and utility sheds. Provides a tough, flexible, synthetic rubber seal.

*** Amazon also has Eternabond RoofSeal white 4” x 50’ for $54.90.

*** Amazon also has the 3M 4000 Marine Sealant for $8.23 and $13.46.

I am sure that there are other sources for these products but hopefully this info is a starter.

**ShrimpBurrito** · 12-03-2010, 09:55 AM

Excellent summary, thanks for posting. Which did you decide to use? I just noticed a similar leak in our unit during very heavy extended rains (like at the end of 48 hrs of raining), and it was a very slow leak. I took a look up there when I got home, and I'm wondering if the leak is not where the mounting plate meets the roof, but rather where the coax goes down into the base. There was some caulking in there, but not much. Pooled up in there long enough, I'm wondering if it eventually soaked through. I don't know exactly how that antenna is mounted, but if that's the case, you could end up removing the antenna and reinstalling only to have the leak continue.

Dave

**Bill** · 12-03-2010, 10:06 AM

Wayne -

The coax entry into the base is a notorious water entry point. There should be a rubber boot that covers this joint, but it is sometimes found either to have moved up the cable and off the joint, or to be missing entirely. With the boot in place, I have had no problems. I'm not sure I would try to seal this joint with caulking ...

Bill

**ShrimpBurrito** · 12-03-2010, 10:26 AM

Bill - That's exactly where I am talking about....I didn't realize the point had such notoriety. My boot was in ok condition, but I don't think it provides a tight seal around the cable any longer....it looks a little loose. I have a new one I could put on there, but of course there is no way to get it on there with disconnecting the cable. I have some stuff called Coax Seal that I am going to put on there, and I might even cut off that boot before I do as it would be a much better seal. I put it on all the coax connections on our roof antennas (on our house), and in the few instances where I have had to remove it to disconnect a cable, the connectors look like new, despite the salt air we have from the ocean and the intense UV here in SoCal. Highly recommended stuff, and it's not expensive.

http://www.coaxseal.com/

Someone on eBay usually has it pretty cheap. You would only use 1 strip for this application. Here's a listing for 10 strips for $3.50 delivered.
http://cgi.ebay.com/Coax-Seal-10-pieces-/190468134256

Dave

12-03-2010, 05:12 PM

Quote:

Originally Posted by ShrimpBurrito

Excellent summary, thanks for posting. Which did you decide to use? ...."

ShrimpBurrito, after posting, I was curious what products in my earlier list are carried by Home Depot so I went online to check it out. I was pleased to find that their online site will also tell you what your local store has on hand.

Of the choices I listed earlier, I found that they had the 3M products in our local store for about the same as Amazon's price; so, I went there and got a 5000 (permanent) tube - it is faster curing than the 4000 UV. Also, because the 3M product is NOT self-leveling, I thought this would be the better product for my antenna problem. Tomorrow, I will scrape the old and reseal with the new.

BTW, I forgot to mention earlier that my leak seems only to drip when the antenna is in upright position. When I lowered the antenna during the rain, the drip seem to stop.

What's that Forest G. saying: "Life is like a box of chocolates ..."

12-04-2010, 06:28 PM

There is a lot of talk about the 4k and 5K sealants. After researching this a lot myself I ended up doing a blend of eternabond around the vents and AC and sealed the trim on the top and sides with the 4K. I ended up choosing the 4K because it's much more flexible. 5K will seal but it's much more rigid and from the posts I saw on the marine forums truly permanent meaning stronger than many of the materials it's holding. That would make for difficult removal if necessary.

I dealt with the antenna by lifting the boot up put some of the 4K around the cable and then slipped the boot back on then wiped off the excess.

Good luck!

12-06-2010, 09:18 AM

Quote:

Originally Posted by greentrail

... I dealt with the antenna by lifting the boot up put some of the 4K around the cable and then slipped the boot back on then wiped off the excess....

Thanks greentrail, I did basically the same treatment for both boot and cable. However, while I had the boot up, I looked closely at the cable and I really don't see how it can leak there while the TM is standing still in a fairly gentle rain.

I think if the leak continues, I may need to spread my re-caulking efforts to other parts of the roof.

Good luck to you also.

12-07-2010, 08:30 PM

A simple tie wrap placed above the antenna boot will keep it from sliding up...

12-07-2010, 08:31 PM

Quote:

Originally Posted by TravlinOn

Thanks greentrail, I did basically the same treatment for both boot and cable. However, while I had the boot up, I looked closely at the cable and I really don't see how it can leak there while the TM is standing still in a fairly gentle rain.

I think if the leak continues, I may need to spread my re-caulking efforts to other parts of the roof.

Good luck to you also.

Water can wick down the cable itself, not from under the boot. Had the problem on our previous 3124.

**Bill** · 12-07-2010, 09:43 PM

Quote:

Originally Posted by MisterP

A simple tie wrap placed above the antenna boot will keep it from sliding up...

Well that's a uniquely simple idea that ought to work very well! Thanks! I've gotten real tired of sliding that boot back into place, but it never occurred to me to actually do something about it.

Bill