I just finished installing an entry door T-latch on my 2018 Arctic Fox 29-5T 5th wheel. It was a chore and a half. It would have been a lot easier had I attached it only to the outside wall of the RV instead of drilling all the way through to the inside, but I thought it would be more secure going all the way through the wall.
Certainly, many successful entry door latch installations have been made by attaching the latch only to the outside wall of the RV, sometimes, I imagine, using backing blocks inside the wall for added strength, but I have read about plastic latches being snapped in half by the force of the wind or being torn from the wall by wind or someone tugging on the door not realizing the latch was engaged. Because of these things I opted for a stainless steel latch for strength and durability. Such a latch wouldn’t likely break but more likely tear from the RV wall if enough force were applied to the door by the wind or unknowing person. In order to avoid such a fate I decided to drill clear through to the inside and reinforce the installation with metal backing plates to distribute the forces over a larger area of the thin luan wall. I did not trust the strength of screwing into the thin luan of the exterior RV sidewall. Nope.
Going clear through the wall introduced considerations that wouldn’t need to be addressed when attaching a latch only to the outer wall. In the latter case it’s often just a matter of picking your spot and running in the mounting screws. In going clear through the wall, however, I had to make sure the screws would come through to an area clear of obstacles that might prevent me from attaching nuts and backing plates on the inside, where there’d be enough room to work (see photo immediately above), and that nothing would be damaged such as wiring or plumbing. This made locating the position for the latch one of the most time consuming parts of the job. I also had to find a method of making sure the drilling angle was near perfectly perpendicular to the wall because any error in the drilling angle would be amplified due to the thickness of the wall–the holes inside could be in very different places than on the outside. In the diagram immediately below I attempt to show how error is increasingly magnified as thickness and distance increase. With the walls of the RV being about 2″ thick drilling precisely perpendicular to the wall became an important consideration.
Apart from the considerations of where I could successfully drill through the wall were the considerations of where best to place the latch from the point of view of functionality. With a T-style latch such as this you have to reach between the RV side wall and the opened entry door in order to operate the latch. If the latch is placed too close to the door hinge it could be difficult to reach in behind the door in order to operate it. Not being a physicist or mathematician and just going on a gut level hunch I was also concerned that the forces placed on a latch closer to the door hinge would be greater than forces placed on a latch further from the hinge and closer to the opposite edge of the door. Here I am talking about leverage. For these reasons I wanted to place the latch as far from the hinge as possible, and as close to the edge opposite the hinge as it could be positioned. I discovered, however, should I place the latch all way at the opposite edge of the door from the hinge that the drain pipe for the sink inside where the screws would come though would be in the way of attaching the backing plates and nuts (as seen in photo above) so I placed the latch a few inches from the edge of the door instead, still close enough to the edge that reaching behind the door to engage and disengage the latch would be easy and the forces applied by the wind would be leveraged as little as possible.
In shopping for a latch I noticed they were offered with T-bars of various lengths, so I set about figuring out why that mattered and what length would be best for my situation. I figured that the further open the door was when secured by the latch the less likely the wind would be to catch the door and the less force the wind would exert on the door and latch. This argues for the shortest T-bar (shank) length possible. There are, however, other considerations such as how far the door will open, where the latch components will be placed, and when will the T-bar be so short you can’t get a hand between the RV sidewall and the door to operate the latch. In order to figure out how long the T-bar of the latch should be for my situation I opened the door as far as it would easily go and measured from the RV sidewall to the door at the spot I had determined the latch needed to be placed. I figured a shank length of about 5 to 6″ should work for my application. (See illustration immediately above.)
I decided to place the T-bar portion of the latch on the wall of the RV and the receiver portion of the latch on the door as opposed to the other way around. I don’t remember why, to be honest, or if it would have mattered. I can see that in some cases, where the T-bar hangs might make a difference. If, for example, it was attached to the door and it hung past the door frame over the stairs it might be in the way or contact the stairs.
One consideration in selecting a latch is whether or not the T-bar, the shank, will rest or rattle against the side of the RV when the latch is not in use. This could potentially mar the RV’s door or side wall. Some people have used little pieces of material such as rubber, gluing it in place somewhere in order to prevent this from occurring. The shank of the latch I selected will not contact the RV when it is not in use. Not having seen the latch before I ordered it his wasn’t something I could plan, but I’m glad it worked out that way.
In order to minimize the likelihood of drilling into something I shouldn’t inside the RV wall I obtained diagrams from my RV’s manufacturer of where framing members in the wall were placed. I could see that I wouldn’t have to worry about hitting anything inside the wall. I could also tell there wasn’t any pluming or wiring in the wall in that area. Thus, my concerns were to avoid hitting the sink drain or drilling into any cabinet framing.
Having worked out exactly where I wanted to drill I needed a method to assure that I drilled straight through at as close to 90 degrees to the walls as possible. I found a tool that would help me do so, a drill guide. I bought one called DrillBlock (see photo). It holds the drill bit at 90 degrees to the surface into which you are drilling while allowing you to place the drill bit nearly exactly where you want the hole to be.
I measured everything twice and then twice more. The last thing I wanted to do was to put a hole in the side of the RV in the wrong spot. My planning and execution were, fortunately, spot on this time.
I wet-mounted the latches with Dicor non leveling lap seal on the back of the mounting plates, but probably many other sealants wold work as well. I opted to avoid an adhesive sealant in case I later need to remove the latch from the sidewall, and because both the T portion and receiver of the particular latch I had selected latch sit in plastic housings using an adhesive wouldn’t add any strength–only the housings would be adhered to the sidewall, not the latch mechanism itself. I also wrapped some butyl putty tape around 1/2″ or so of the screws near the heads to help fill any gaps where they penetrated the RV exterior wall and latch hardware. Finally, I silicone sealed around the perimeters.
Tools and Materials
Podoy RV T Style Stainless Steel Latch
Four 3″, 10×24 stainless steel pan head Phillips machine screws for mounting on the RV wall
Four 2″, 10×24 stainless steel pan head Phillips machine screws for mounting on the RV door
Eight 10×24 stainless steel nylon lock nuts
Four 4″ x 1″ x 1/16″ strips of aluminum for backing strips because that’s what I had on hand. I’d have preferred something more like a 4″ x 4″ x 1/8″ aluminum backing plate for each of the two latch components.
Dicor Butyl Putty Tape
Dicor Non Sag Type Lap Seal
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