Mystery of Leaking Front Left Roof Vent Solved

Steppy · 04-27-2018, 09:52 AM

I purchased my TM last Feb and after some snow and rain, noticed water leaking from the front left roof vent. Yesterday I finally got a clear day to tackle the removal of said vent and base to install it correctly. Lo and behold, the water was coming in through one of the vinyl base butt joints, none of which, BTW had a vestige of any type of sealer or caulking, an omission I lay at the feet of the TM factory. There was plenty of cau
lking gooped on all over the outside of the vent and base, which was ineffective in preventing the leak. From the appearance of the butt joint itself, and the internal rusted clamp holding down the vent to the vinyl base, the leak had been there a long time.
I hate scraping and removing old caulk/sealant. I used a putty knife and razor blade scraper to remove the most and then used Goof Off to remove the vestige. What do y'all use to remove old caulking?

I cut new PVC strips for the base and when it stops raining will be using 3M Marine Adhesive/Sealant 4000 UV to re-bed the base and vent, first clamping the base until it cures, then the vent.

I had similar leaky issues with my 2004 2720Sl TM, again, caused by poor factory installation where the vinyl base was screwed on to the roof without first being pre-drilled, causing cracks in the vinyl everywhere there was a screw. For what these TMs cost new, one would expect better quality craftsmanship. Here's hoping the new TM factory owners take heed.

**Larryjb** · 04-27-2018, 10:27 AM

I noticed this too. Are you sure it came from the factory like that, or did vibrations, heating, cooling, and flexing cause the separation of the but joints?

I did notice that the screws can leak, even they appear to be sealed. I had to remove all the screws, ooze RV sealant into each screwhole, then re-insert the screws. This solved all my leaking issues so far.

Shane826 · 04-27-2018, 12:17 PM

I rebuilt my vents using 3M 4200 adhesive sealant. I put a bead on the bottom of the riser, smooshed it down on the roof. Put a bead on top of the riser, smooshed the vent down on top of it. Had an assistant screw the assemblies together to “clamp” them to the roof while I tooled the smooshed out adhesive to make it look nice and smooth. Haven’t had a leak from the vents since then.

Steppy · 04-27-2018, 12:52 PM

Quote:

Originally Posted by Larryjb

I noticed this too. Are you sure it came from the factory like that, or did vibrations, heating, cooling, and flexing cause the separation of the but joints?

I did notice that the screws can leak, even they appear to be sealed. I had to remove all the screws, ooze RV sealant into each screwhole, then re-insert the screws. This solved all my leaking issues so far.

As I said "Lo and behold, the water was coming in through one of the vinyl base butt joints, none of which, BTW had a vestige of any type of sealer or caulking" and I mean nada, zilch, zero on any of the 4 butt joints.

I made a new vent base and used the 3M on all the joints and screwed them together, eliminating the possibility of water migration through them.

After this sets up, I'll install the vent itself, clamping it like I did the base. Just using the 4 interior vent clamps IMHO won't insure good contact in the middle between the corners of the vent. I do NOT want to mess with this vent EVER again!

rollsrep · 05-17-2018, 06:34 AM

What are the dimensions of the pvc riser? Any idea where to buy the material? I am getting ready to do this job and want materials on hand before I start. I have an '02, so I'm assuming my riser is rotten wood......

**Larryjb** · 05-17-2018, 07:16 AM

Mine is an '02 and has the pvc riser. I put some RV sealant into all the joints then used Terabond.

One could get vinyl wood from Home depot and cut it to size. Then you could use lap joints. Bert cutting vinyl wood is very dusty, and it's not a nice dust either.