Roof Radius Caulking Cracks

**creativepart** · 02-09-2023, 10:28 AM

I check my roof radius drip rail caulking once or twice a year. My motorhome is 6-years old now. So, I checked it today, again.

The caulking appears to be Manus Bond 75 - which is what WBGO says it is. I've used Manus Bond before on a small opening on the cap radius. So, I know what it looks like.

For just about the entire roof length the caulking looks OK. But the first 2 ft of drip rail, on both sides shows some cracking. Since it's both sides I'm guessing there is some flex up front and this is why it's only in this area.

Here are two photos of the "good" section and the "bad" section. I'm thinking I'll just remove some of the cracked caulking and reapply Manus Bond 75 to that 2' or so.

The filon roof radius is not even slightly loose. There is zero movement when pressed at the point the filon enters the drip rail.

bigb · 02-09-2023, 11:46 AM

That's right where mine started, at the front. I re-did it all with Proflex about 1.5 years ago but recently noticed a slight separation on the pass side front about 7" long and like yours, it is in the middle of the bead and the filon appears to be still tight. I got a fresh tube of Proflex and it's on my to do list to clean with alcohol and touch up.

**creativepart** · 02-09-2023, 11:51 AM

When you "redid it all" you mean you dug out all of the original caulking the entire length and resealed it with Pro-Flex?

Was your cracking the entire length of the coach when you decided to "re-caulk" the drip rail?

bigb · 02-09-2023, 12:04 PM

Quote:

Originally Posted by creativepart

When you "redid it all" you mean you dug out all of the original caulking the entire length and resealed it with Pro-Flex?

Was your cracking the entire length of the coach when you decided to "re-caulk" the drip rail?

I did more than that, since the radius needed painting I removed every bit of old using small diameter wheels on a die grinder and lots of chemicals. I also stripped and sanded the filon, primed and re-painted with a two part catalyzed automotive paint using HVLP. The details are in this thread: https://www.winnieowners.com/forums/...ml#post3901615

Park Super · 02-10-2023, 07:44 AM

Do yourself a favor and use Manus Bond 75, not the Pro-flex.

Americanrascal · 02-10-2023, 10:31 AM

Creativepart- Mine has had a similar situation. Primarily about 3' over the left drivers side and then about 3 foot at the rear right pass side where the filon fits into the j rail groove. In my case I cleaned out the old sealant/adhesive and replaced with Proflex the first time. THAT WAS A MISTAKE. It did not hold up and within 2 years I had to replace it.

I wish I had not used the Proflex and now I am back to maintaining deteriorating areas along the j rail with with Manus Bond clear 75 AM.

Initially I had become somewhat infatuated with Proflex, but I have to admit it just did not hold up as I thought it might.

Joe

**creativepart** · 02-10-2023, 10:54 AM

I've heard this same story from a number of other owners. So, I'm not thinking of ProFlex at all. As I mentioned, I worked with Manus Bond and that fix has held up fine for 3 years and still looks like new. I think Winnebago gave up on it for some reason... cost? availability? difficult to work with? I don't know. But I do think it's good stuff and I'll be using it.

I don't plan to remove all of the cracked caulking. I'm going to open up the crack much larger and then fill it and cover the filling with Manus Bond. But just the cracked areas. Not the whole 65' of drip rail.

BobC · 02-11-2023, 07:59 AM

Quote:

Originally Posted by creativepart

I've heard this same story from a number of other owners. So, I'm not thinking of ProFlex at all. As I mentioned, I worked with Manus Bond and that fix has held up fine for 3 years and still looks like new. I think Winnebago gave up on it for some reason... cost? availability? difficult to work with? I don't know. But I do think it's good stuff and I'll be using it.

I don't plan to remove all of the cracked caulking. I'm going to open up the crack much larger and then fill it and cover the filling with Manus Bond. But just the cracked areas. Not the whole 65' of drip rail.

Wouldn't it be better, and not much more work, to remove all the sealant from cracked areas before replacing it? I think it would result in a better repair.

bigb · 02-11-2023, 08:06 AM

I was sold on the Proflex after watching the AZ Experts videos and many here recommended following the advice of AZ Experts. Now, after hearing reports of short lived repairs I kind of wish I had used something else. It will be a real pain to remove it all and start over, especially with my nice new paint up there. Hopefully it holds up although the slight separation I have is not too encouraging seeing as Winnebago's product lasted 10 years. I am stored indoors with only about 4-6 weeks per year of use right now so hopefully that will help.

Ray,IN · 02-12-2023, 06:44 PM

I tried something different 4 years ago and it's still looking greatl Flex-Seal white coating applied with a small brush ran down into any voids and filled them then left s smooth even bead.
It took me one day to clean and apply the sealant to each side of my MH.

tim myers · 02-14-2023, 09:33 AM

Please correct me if I am wrong, but the function of the caulk on our Roof Radius Caulk is mechanical and not for water proofing. The caulk keeps the radius tucked inside the extrusion which also acts like a gutter to run away any moisture. As long as it is keeping the roofs edge from coming out of the extrusion you are ok?

I had mine completely removed and reapplied a couple years ago but check it at least twice a year, and have also noticed some cracks in the first 2 or 3 feet at the front of the Journey.

Always learning aren't we?

**creativepart** · 02-14-2023, 09:41 AM

Quote:

Originally Posted by tim myers

Please correct me if I am wrong, but the function of the caulk on our Roof Radius Caulk is mechanical and not for water proofing.

I believe that is true.

I plan to still just fill the cracked area with Manus Bond 75 after widening the cracking in the caulking. If when I open up the crack the rest of the caulking seems at all loose I will then remove that whole section (only) and recaulk just that area.

Even in the section showing the most cracking there is zero movement in the tucked in roof material. You can't push it in or pull it up even a tiny amount.

BobC · 02-14-2023, 09:41 AM

Quote:

Originally Posted by tim myers

Please correct me if I am wrong, but the function of the caulk on our Roof Radius Caulk is mechanical and not for water proofing. The caulk keeps the radius tucked inside the extrusion which also acts like a gutter to run away any moisture. As long as it is keeping the roofs edge from coming out of the extrusion you are ok?

Your premise is correct. The extrusion is below any areas that could cause a water leak and, if I remember correctly, the extrusion has weep holes. What I don't know is whether or not cracking is a precursor to mechanical failure.

**creativepart** · 02-14-2023, 09:47 AM

Quote:

Originally Posted by BobC

What I don't know is whether or not cracking is a precursor to mechanical failure.

I could seen cracking being a precursor to loosening and that loosening enabling the roof coming out of the drip rail.

Though just looking at it it seems it would have to have no caulking left in there at all. Seems realitively simple to keep doing some basic maintenance on an regular basis.

When James/AZ Expert shows these failures it looks like a ridiculous system that can't work - but on my 6-year old coach with nearly 50,000 miles of usage it seems solid as a rock.

Perhaps it is just a bad initial install at the factory that is not recognized before shipping???

Americanrascal · 02-14-2023, 11:24 AM

Please correct me if you think I am off here, but my understanding of the material (Manus Bond 75AM or Proflex) to be used in the roof gutter system is to serve as both a sealant AND an adhesive to secure the filon edge to the coach rail. Absent the adhesive capability of the material, the filon will pop out and begin to flop free and eventually pull away from the roof.

That actually happened to me on my former 2014 Itasca when on the right rear I found the filon had popped out of the rail when the sealant/adhesive failed ( it was 2 years old) in the rail. I was able to clean out the rail and reinstall the filon with adhesive/sealant and the repair held.

cruizerEd · 02-15-2023, 04:14 PM

Quote:

Originally Posted by Park Super

Do yourself a favor and use Manus Bond 75, not the Pro-flex.

I did the pro-flex. The UV is eating it up fast.

AZ experts made pro-flex popular but his position is just replace it when it ages out. That is a real PITA or real expensive.

Guess it is good if you're the guy getting hired to redo it.

Farco · 02-15-2023, 05:07 PM

First off, use Pro-Flex CLEAR.
It holds up longer.
Do not use the Manus bond.
Manus chalks up and breaks down fast.
Winnebago stopped using it.
I did mine with Pro-Flex two years ago and is still tight.
Pro-Flex keeps its elasticity the best I’ve seen.
It’s important to clean out the channel as much as possible.
I used mineral spirits and an automotive seal puller. This tool has a flat hook on the end and scrapes out old sealer down to the bottom of the channel nicely.
It’s important to jam the tip of the caulk gun into the channel and pump it completely full as you go.
You will waste a lot, but it will adhere and seal really well.

Park Super · 02-16-2023, 07:27 AM

I used that proflex and had really poor results. AZ expert video convinced me to try it. I was removing it and replacing it with Manus bond just 2 months after completely cleaning the old adhesive out and replacing with proflex. Very disappointed. Anyway, I have contacted Winnebago and Lichtsinn rv asking what this part number is (SS0030-01-000 SEAL SPEC-JOINT, ROOF-TO-S/W) that is called out on the 2023 class A rvs. Wanted to find out what they are using now. I will respond when I get an answer.

bigb · 02-16-2023, 07:32 AM

Anyone considered 3M 5200?

**creativepart** · 02-16-2023, 08:18 AM

Quote:

Originally Posted by bigb

Anyone considered 3M 5200?

In another thread on this topic someone posted that 5200 was too rigid and that 4200 remained flexible. I’m not sure of all that but flexibility is required for whatever is used there. So if that’s the case then 5200 would not be appropriate.