Class C motorhomes, Do they all leak?

[rvnetter]

We've been looking for a used Class C motorhome. Every one that we've inspected, has had visible signs of water leakage/damage specially over the cab area. Can't manufacturers find a way to build these without having leakage issues? Frustrating!

[ron_dittmer]

I am glad to read that you who have class Cs with seam work in your cab-overs are maintaining them properly. But I think the original posting question is with regards to which class Cs are less prone to water infiltration. That is why I stress a seamless cab-over front, a fiberglass roof that is rolled over the edge & overlaps the sides, and finally a rear cap where the actual sealing joint is away from the corners.

Affordability versus reliability. That is the matter at hand. If your level of affordability places you into an entry model with trouble prone seam work, be diligent with your inspections and prompt reaction to early signs of water infiltration, and you can enjoy ownership just like the people who spent more on higher end ones that are better sealed.

If my class C (actually a B+) was stored outside all the time, with winter approaching fast, I would want to "tarp" the roof and sides to protect it from the worst of water damage potential. Maybe not needing a full covering, but at least to a point. It would be nice to be able to get inside during winter so don't tarp it too well.

Ron

[Harvey51]

I thought my metal roof had a serious leak problem and just about opened the cabover ceiling to see what was wrong. However, I finally deduced that there could be no leak in the metal or in the cap so it had to be the joint. Removal of the old caulking made caulking defects visible. Fresh caulking and a strip of 4 inch eternabond for the full length of the join seems to have fully dealt with the leaking.

Got another leak into the back of the fridge last summer. Quite a bit of water, clearly coming down from the fridge roof vent. Caulking problems there, too, under the big plastic vent cover. I caulked. At the first sign of trouble, I will remove the top piece and replace the caulking between the metal roofing and the plastic insert holding the screen instead of just caulking around it.

[mrmomb]

garyhaupt wrote:
Yes..they all leak..but, so do all houses if they are not looked after.

One of the things to look for then, is a C manufactured using metal framing as opposed to wood. It's the repairing of the rotted wood framing that will cost the HUGE dollars. With a metal framed unit, you repair the leak, tear out the interior wall replace the insulation and put the wall back up. No rot to contend with.

As for leaks...the clearance lights and the seams around the cap are the biggest culprits. DO NOT buy a C with a fabulous front window in the cap. Then the windows. Those can all be removed and re caulked by yourself or a shop. Then the roof itself can leak. Any place on the roof where it has got stuff into it..thru it...the A/C housing. TV and Sat cables. Vents..are all areas to check, but...again..they all leak sometime. Getting it repaired is always the key.


Gary Haupt

Excellent post!! Kudos. Well written. I agree with all your points.

I do have a squared off leak prone cab over. Routine inspections and protective eternabond tape are my preventative measures.

[ron_dittmer]

AreCF wrote:
What is a "compromising partial bucket design," for the roof cap. One of the posts on this topic indicates that Nexus uses this type of roof construction.

Look close at the two pictures. The topic and focus here is with regard to the sleeping quarters over the van portion.

This rig has a partial bucket design. Note the front facing part of the upper bunk is like a pan standing on it's edge at an angle rearward with shallow sides going rearward. It places the seams approximately 6" behind the actual corners.


Now look at this overhead bunk. There are NO seams until you get much farther back by the black vertical awning support. This is a full seamless bucket design where there are NO seams in the cantilevered section above the van portion.

Don't be fooled by this picture. What appears to be a horizontal seam that crosses above the side window in the upper bunk is only a bend in the fiberglass, assumed to prevent the side wall from resonating and for additional strength.

[AreCF]

What is a "compromising partial bucket design," for the roof cap. One of the posts on this topic indicates that Nexus uses this type of roof construction.

[ron_dittmer]

rvnetter wrote:
Thanks so much for all of the replies, especially Ron.

Your Tin Tent is better yet when it comes to water leaking in. 🙂

[rvnetter]

Thanks so much for all of the replies, especially Ron.

[Toot_Mc]

My coach house is now 10 years old and with zero maintence on roof has never had one leak. Coach made with fiberglass shell is made with one piece except for slide. Has not one stain any place and Has never leaked. It is very quite with not much road noise on the highway.

Paint system also very good with 2 coats of clear coat and after 10 years it looks like new except place where I rubbed rear bumper on tree trunk.

[Bordercollie]

Open side window weep holes, seal other stuff, don't use silicone sealers. Bumpy, Visit CA, OR, and WA.

[Bumpyroad]

Bordercollie wrote:
Don' buy a used rig with stains, mold smells or other signs of water damage. Have your rig tested periodically for leaks and have leaks sealed with proper sealants and techniques including cab-over windows and clearance lights as well as side window weep holes, roof vents, AC unit, etc. All RV roofs can develop leaks over time from rough road shock, sun damage, etc.

you want the weep holes plugged???????????
bumpy

[Bordercollie]

Don' buy a used rig with stains, mold smells or other signs of water damage. Have your rig tested periodically for leaks and have leaks sealed with proper sealants and techniques including cab-over windows and clearance lights as well as side window weep holes, roof vents, AC unit, etc. All RV roofs can develop leaks over time from rough road shock, sun damage, etc.

[DrewE]

ronfisherman wrote:
I find it interesting when looking a some RV roofs. They are almost black. Hard to find leaks when you cannot even see the roof. My 12 year old MH roof is almost as clean as the day it was manufactured. Probably better because my roof had a tare in it near one of the roof vents that leaked bad on our way home from purchasing it in AZ. I stopped the leak with some duct tape until we got home. Then did repair with Eternabond. Over 10 year later never had a leak again.

Black on the roof may not be dirt, but rather the thin outer white layer of some roofing membranes having worn off the underlying black roofing material. (Somewhat ironically, this can be hastened by excessive scrubbing).

[tatest]

No. Mine is at least 12 years old, has not leaked yet. When buying used, you'll see leaky RVs, that's why they are being sold, owner did not want to deal with the problem.

[ronfisherman]

Good info from ron.dittmer.
I find it interesting when looking a some RV roofs. They are almost black. Hard to find leaks when you cannot even see the roof. My 12 year old MH roof is almost as clean as the day it was manufactured. Probably better because my roof had a tare in it near one of the roof vents that leaked bad on our way home from purchasing it in AZ. I stopped the leak with some duct tape until we got home. Then did repair with Eternabond. Over 10 year later never had a leak again.