RV Roof Construction

I have a question about truss style rafter construction for my walk-on roof. I wish to run a cable through/across the rafters towards the front of my trailer. My question is how are these rafters made and most importantly are they hollow?  I am trying to accomplish this without any drilling through anything. It is a PacificCoachWorks trailer 2014. Bill M.

Bill, according to Pacific Coachworks, all PCW units have wooden roofing structural components, including their trussed-roofed trailers. It would be very difficult to route any conductor or cable though the roof. But because they have ducted air conditioning, it might be possible to snake a cable alongside the duct work, at least part of the way. Depending on what you’re installing and how far the run would extend beyond to two extreme ducts, of course. Though the sidewalls are constructed using hollow aluminum tubing, the rafters are all solid wood, unfortunately.
 

TV Shelf Removal

Hi Gary, I enjoy the reference material that your site has accumulated. We own a 2002 Komfort 23-foot travel trailer. In the Master bedroom there is a small corner shelf that an old CRT-type TV sits upon. My wife is always hitting her head on this shelf. I would like to remove it and install a flat panel TV on the wall. I can't figure out for the world how to go about removing it. I am not sure if the trim that runs along the outer edge if removed will show long screws, or if it is attached through the outer wall before it is skinned? There are no visible attaching mounts. I and my wife hope you can help me. Thanks for your time! Ed S., (no city/state)

Ed, I believe you are correct; that the shelf was likely installed prior to the installation of the exterior siding of the coach. The screws probably run from the outside, through the interior paneling and into the shelf. It is possible to cut through the mounting screws between the shelf and the interior panel, but there is a risk the panel will be damaged. A good technician with a careful hand and sharp tool should probably be able to accomplish the task easier. Because of the risk of water intrusion, I would advise against removing any of the exterior components. And even when the attaching screws are cut and the shelf removed, you’ll still need to hide the remaining screw holes and any other evidence of the shelf. Unless, the new flat screen will effectively hide them. Of course, you can always put the pillow at the other end of the bed, but I’m guessing that wouldn’t be a real option!. And probably not one to suggest to your wife!

Delamination Dilemma

I have a 2004 RV with a wood frame. Last summer I noticed what I believe you call "de-laminating" on the front section. The camper's exterior fiberglass appeared to be rippling. I suspected this was related to a leak so I resealed the entire front of the RV. Recently, during a heavy rain storm, I found some water in a closet which verified there was in fact a leak and also that I didn't catch it when I resealed the RV. If I can get the leak to stop will the "de-laminating" continue? Can you repair "de-laminating" without pealing back the entire exterior? If I get the leak to stop, will problems continue (dry rot etc.)? Am I in deep trouble or what? Dennis D., (Klamath Falls, OR)

Dennis, in many cases, wood frame construction is relatively easy to fix in the event that there is any damage to the structure. You are correct in that the leak source must be identified and stopped before repairing the damage. If you are having a problem finding the leak, carefully and thoroughly inspect all moldings, fixtures, window frames, and lights. Re-seal any areas that look questionable, even if you do not find any breaks or voids. To be 100% sure where the leak(s) are located, check out this short video.

Stopping the leak is the important first step, but delamination usually occurs only after the underlying wood and framework have become saturated with moisture. Even after stopping the leak, the wood can stay wet due to the absence of airflow and further damage could result. Some people proclaim you can inject glue behind the delamination and stick it back down. Typically this is a waste of time and effort, as you cannot get glue to stick to old adhesive and wet wood for very long no matter what you use. Also there is no opportunity to repair any underlying damage or even time to dry the wood effectively. 

If delamination occurs and the area of the damage is small compared to the size of that section, a good body expert can repair the damage with a patch. In your case of delamination on the front of a RV, I would recommend replacing the entire front, as it is a relatively small area and the cost to replace vs. repair (if the damaged area is small) is insignificant, especially when you consider the integrity of the repair. Replacing the entire front is guaranteed to be a more robust repair than a patch. A patch is also not an option if the damaged region spans a significant area. The repair process involves stripping the moldings and other fixtures, and removing the fiberglass panel from the wood frame. The insulation is removed in order to dry the wood frame and interior wall panel. This drying stage is very important for proper repair.  Any water damaged wood framing is replaced, new insulation installed, and the wall material replaced with new, including any backing that was used on the original. 

In the case of a patch, it is done the same way, except only the damaged portion of the fiberglass is simply cut out. Then the framing is dried, repaired and a new section of fiberglass is inserted into the cutout and the joints finished with fiberglass cloth and painted. This is a relatively complex repair job and I don’t recommend you attempt it yourself. Seek out an RV repair facility experienced in collision repairs. The job should not be overly cost prohibitive, since a front wall is not a large area to repair, however, such things are subjective! 

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Leaky RV Window Can Cause Structural Damage

My husband and I own a 4-Winds Hurricane. When we first purchased it, pre-owned about five years ago, from an elderly neighborhood couple, we had not planned on it. It just kind of happened and we couldn't be happier. However, initially there was a little bubble in the fiberglass shell below the back bedroom windows. We were told that the windows were put in backwards and water had gotten in but the windows were corrected and no problems since. But over the last couple years, the bubbles have gotten bigger and where our pleated shade screws into the wall below the windows inside, they pulled loose. It is soft inside the holes and we fear we may have to replace the inside wall. What exactly is involved and what kind of money are we talking about? We love our RV and keep her immaculate. We want to keep her for many more years as she has given us such great memories. One especially...my mom died a couple years ago and I had the opportunity to take her camping and she loved it. She had never done anything like that in her life. So can it be fixed and can we save her? Angie L. (Trainer, PA)

Angie, it was so nice that you got to take your Mom RVing! You can forever know the joy you brought to her on that trip.

I'm a little confused about having the windows installed backwards; that's really not possible. Upside down, maybe, which would definitely result in a water leak. In any case, it is apparent moisture has invaded the interior walls. If indeed the window leaks have been stopped, it's possible only relatively minor repairs are required. But it will take an expert RV service technician to fully inspect and assess the resulting damage. Some of it may be hidden inside the wall. In minor cases, the delamination of the exterior surface will often cease once the leak is sealed. But if the interior paneling is weakened or rotted, the problem may be more severe. In most cases, the damage can be mitigated. How much it might cost is unknown until the inspection process is completed. I would definitely find a qualified service tech to fully inspect the damaged area. I do have an experienced, Master Certified RV Technician in your area I can refer you to; contact: 

Ron Donachie
Ron’s Mobile RV Services, Inc.
Serving Eastern Pennsylvania
484-225-8211
rondon@ptd.net

He'll come to your door and perform the necessary inspections and to assure all leaks have been eliminated.

Improper Installation of RV Roof

I recently had my rubber roof replaced on my Class C, 22-foot motorhome. The rubber was still good but getting old. But because the old plywood was bonded to foam insulation, they put plywood over it and installed the new rubber roof. Within four months the plywood under the rubber warped really bad. They say they will fix it under warranty but I was curious as to how they do this as it seems the plywood didn't hold the first time around. It's been in the shop over two weeks now and I cannot find anything out yet. How will they attempt to solve this problem? BMCM, (FL)

It’s difficult to ascertain just how they installed that new substrate plywood to the older roof. Hopefully, they removed the rubber membrane, inspected the older substrate plywood for damage, then glued and screwed the new plywood directly to the old plywood after properly preparing it. The condition of the old plywood is crucial. If they attached the new wood to a deteriorated or moisture-damaged substrate, it’s possible the new plywood would buckle in places. It sounds like this may be the case.

They will have to remove the new membrane and the new plywood and thoroughly inspect the old substrate to determine the best course of action before continuing. It is salvageable for sure, but to avoid future issues, it must be done correctly this time. I would also insist on a new membrane. Once they remove the rubber from the new plywood, it will have stretched and been rendered unusable.

Let me know how it turns out. It’s great that they will at least honor their warranty! But they must prepare the old roof properly prior to installing the new roof substrate and EPDM membrane.

Air Leak on RV Siding

I own a 32-foot toy hauler. Recently on a trip, I noticed air getting between the siding and the walls of the trailer, near the leading edge of the sides of the trailer. On my return trip home, the air blew the siding out like a balloon and popped the siding out from behind the edge molding. What I need to find out is where the air is coming in. I am unable to determine this and I would like to repair this myself. Any ideas? Tom, (La Quinta, CA) 

Tom, if air is getting behind the siding, then water can also. I’d recommend a thorough inspection be performed. The first thing I would suggest you do is completely remove the front edge molding on the affected side of the trailer. After the molding is removed carefully clean off all the old putty and sealant and set the molding aside. Next clean all putty and sealant remnants still on the corner of the trailer. Access the roof of the trailer and thoroughly inspect the front roof transition molding for gaps in the sealant, especially close to the front corners. Do the same with any roof fixtures nearby such as roof or sewer vents, TV antenna, etc. Be sure to clean and reseal any cracks in the sealant. 

Back down on the ground, with the edge molding removed, carefully pry open the sidewall as much as possible and use a flashlight to inspect the framework behind (this is assuming you have soft side walls and stick construction). Reach your hand in and feel the insulation. Hopefully it is dry inside. If the insulation is slightly damp it can probably be dried by propping open the gap between the siding and framework and directing a portable heater into the opening. Leave it on for at least 24 hours or until it is totally dry. Reassemble the exterior wall once the innards are dry. 

A staple gun was probably used to secure the edges of the siding to the framework during manufacture but you can use small tacks or staples. Just be liberal with them. The more you use to secure the siding, especially on that leading edge, the less chance of it pulling loose again. Apply Eternabond DoubleStick tape along the inside edge of the molding and reinstall each molding piece. Be sure not to tighten the screws too tight or they will strip. Use a larger size screw or install additional screws in that area if some are indeed stripped already. Make absolutely sure that the molding properly covers and overlaps the bitter edge of sidewall material. 

It is possible that the sidewall skin is cut too short in some areas and that the molding doesn’t completely cover it. This could also be the cause of the air leak. If may be necessary to “cheat” the molding further inboard so that it totally covers the edge of the siding all the way around. If the siding has dips and valleys by virtue of its design, apply more than one layer of Eternabond tape. You’ll want all the gaps completely filled in. Using a utility knife, simply trim the excess and do another thorough inspection for gaps in the sealant.

RV Damage Due to Tire Failure

I have a Class B motor home and was driving down the highway when the rubber from the rear outside tire flew off and took out the insulation and cabinet bottom, water lines and a host of other things. As the stuffing flew out, it caught something underneath on the other side and knocked out the floor under my bathroom cabinet. Is this common or did I just have a bit of bad luck. I would really appreciate knowing while I wait to see what the insurance company has to say. Cory, (Omaha, NE) 

Cory, I would have to say that you indeed had a case of bad luck with that tire separation. The damage caused by a separating tire can either be minimal or much worse in many cases. Road speed, type of coach construction, how large the pieces were, etc., all plays a part. I’d hazard that no two instances will be identical. I would, however, caution you to be sure and let the insurance company know that every system, propane, battery, 120-volt AC, fresh water plumbing, waste water plumbing, etc., will need to be fully tested after all the physical construction repairs are completed. It’s not simply a matter of rebuilding the structural components. There may be unseen damage that can only be revealed through a series of tests on each of the systems.

Plus it's important to fully analyze why that tire failed in the first place! Have a professional service technician or tire safety expert conduct a thorough investigation to determine the cause. Overloading, improper air pressure, faulty tire or other failed equipment may have been the cause and a close inspection is a mandate against further complications later on.

This might be a good time to remind everyone about the great work performed by the RV Safety & Education Foundation (RVSEF). My good friend, Walter Cannon, heads that organization and is the leading expert in tires, weights and safety for all RVs. Be sure to check out the information posted here.

RV Construction - Interior Wall Removal - UPDATE!

I have an older RV I just bought. It is kind of a project for me and one of the things I'd like to do is open up the bathroom area in back. But to do so I have to remove a cabinet and two short inner walls. Not having worked on motorhomes before I am wondering if I can just remove the walls or if they serve some load bearing function. They are located on the back wall and don't seem to do anything but divide space, but I don't want to make a major mistake.
Joel, (Taylors, SC) 

Joel, there are no load-bearing interior walls in the motorhome. You are correct; they are there simply to create separation between areas of the RV and are considered basic partition walls. And I’m guessing every one will be hollow walls at that. You’ll probably also find screws coming into the cabinets from the outside in. These can simply be hack-sawed or cut with a Saws-All. 

Update from Richard Miller: Gary, you recently advised that it was OK to cut an RV interior wall and that the walls in RVs were not load bearing. I agree about the load bearing statement, but I also know that I have black/gray vent pipes and wiring to switches and thermostats located in the interior walls of my 5th wheel. They are not all located in the outside shell walls. The questioner should be advised to proceed with caution after careful examination.

Thank you Richard! You are exactly correct and you may have saved Joel some headaches. Indeed if the partition wall exhibits any type of electrical component, it may be necessary to re-route some wiring before removing the wall itself. Also, if the partition wall appears to be a couple inches wide or more, there could be some vent piping stashed behind there. As Richard mentioned, proceed with caution if any doubt exists.

Thin RV Cap Causes Mounting Dilemma

The license plate and license light bracket are ready to fall off the rear cap of our motorhome. The screws have become loose. How is the best way to reattach these items to a thin wall (about 1/8 inch thick) with foam insulation behind it? There is just nothing for a screw to sink into. Jackson, (Plano, TX) 

The perfect fastener to use in this instance, Jackson, is called a threaded nutsert. Most astute RV repair facilities will have this fastener and its requisite installation tool, especially if they also perform collision repair and other types of RV body work. Nutserts can solve a multitude of mounting and securing issues in aluminum, fiberglass, and other types of thin, RV siding materials. Take a look at this web page for a neat little presentation on how a nutsert is actually installed:

http://www.avdel-global.com/en/products/threaded-inserts/thin-sheet-nutsertr.html

All professional RV service technicians will, (should), have access to a professional nutsert tool. Hope this helps!

RV Gray Water Drains into Black Holding Tank

We have a brand new motorhome produced by a major manufacturer. We like most everything about the rig but one thing about this particular coach really bothers us. Our shower drains into the black tank. Now normally we could dry camp (in our old rig) without needing to empty our black tank for a couple of weeks. Not true here. We have to dump this black tank every single day. We could just give up on showering, I guess. When we contacted the manufacturer about the issue they pretty much told us to take a hike. Are there other motorhomes out there with this same problem and are there any regulations which govern the installation of black tanks at the manufacturing level? If we can't correct this hang-up our $150,000 coach will pretty much be worthless to us, which is just what we've found the manufacturer to be.
Daniel, (Appleton, WI) 

Wow, I’m so sorry to hear of your difficulty with the manufacturer Daniel. It’s unfortunate, but it is permissible for RV manufacturers to allow a liquid fixture to drain into the black water holding tank and still satisfy the requirements of the NFPA 1192, Standard for Recreational Vehicles. This is typically predicated by the design of the floor plan. In my opinion, not the optimum situation.

Most makers, thankfully, do keep the black and gray waste systems separated and relegated to dedicated holding tanks. In those few instances where a gray waste fixture does drain into the black holding tank, typically it will be an infrequently used device like a lavatory sink. Based on your description, it sure sounds like a very poor waste system design.

Now having said that, in some instances, it is possible to re-route the shower drain to the existing gray water holding tank, or better yet, to a newly installed third tank. A competent RV technician will have to inspect the existing waste system to see if that option is feasible. All drains must enter the holding tank at the top of the tank, so gravity filling from the side or bottom of the holding tank is not allowed. A thorough inspection will determine how best to accommodate the modification. I wish I had a more definitive direction for you. But try to find an experienced RV repair facility in your area that can make the alterations. All is not lost yet!

Galvanic Corrosion

Why does a well-known RV manufacturing company insist on using dissimilar materials in the roof construction? They must be aware, like many others are, that steel staples (as well as stainless steel staples) will be subject to electrolysis when combined with aluminum sheeting. I ask this question because my RV is currently in for a roof repair and the root cause of the roof problem would appear to be caused by rotted staples that have been used to hold down the aluminum corner panels.
Barry, (Yuma, AZ)

Great question Barry. Technically what you are referring to is called “galvanic corrosion,” as opposed to electrolysis. Galvanic corrosion is basically a current flow that occurs between dissimilar metals causing primarily oxidation and rusting. There are a few things to bear in mind when thinking about galvanic corrosion. First, galvanic corrosion requires a corrosive medium in order to occur. And indeed water can act as this medium. However, if the materials are kept dry galvanic corrosion will not occur.

Secondly, in terms of corrosion-resistance, metals are often classified as active (least resistant) and inactive (most resistant). Galvanic corrosion increases the resistance of active metals and decreases the resistance of inactive metals. What this means is when a small area of inactive metal (the staples) comes into contact with a larger area of active metal (aluminum roofing), the effect of the corrosion is greatly minimized. As a result, using stainless steel staples with aluminum sheeting is acceptable given the large differential in the surface area.

Theoretically, the roof staples on an RV are not supposed to get wet and are therefore not susceptible to galvanic corrosion especially when coupled with the active/inactive properties. When galvanic corrosion does occur anywhere on an RV, the primary cause is water leaking into the affected area and it is the cause of both the galvanic corrosion and the wood damage. In your case the “rotted” staples indicates that they probably got wet before the corrosion actually started.

For the most part, I’ve got to believe that RV manufacturers understand the principles behind galvanic corrosion and adhere to somewhat strict processes designed to minimize its potential by properly sealing the area. But water intrusion is indeed an RV fact of life. Proper maintenance to roof edges, seams and moldings must be performed regularly.