thewanderlustking Posted August 11, 2022 Share Posted August 11, 2022 This is kinda a continuaion of my Roof HELP! Other than setting this on fire, any other more realistic options? thread, but I have very specific information I am after and don't want to jumble that thread up. I will leave that one as my "roof rebuild project' lol! I am trying to figure out any specifics of the roof construction and bracing structure that you guys can tell me. I have mostly finished the outer skin repairs, but now I need to move on to the inside structure. And I am trying to figure out exactly how R.B.R. put this together WITHOUT opening the can and peeling the roof off. On mine I can't tell what was original and what has been repaired in the 35 or so years since... I have found a couple references as to the bracing beams underneath. Quote Our previous 86 RBM Mini-Cruiser also had aluminum in the walls but not so in the roof where it was rotten 1x3 wood and rusted thru 3/4x3/4 square steel tube,both have aluminum skin under the floor which keeps any water that gets in from getting out! (I am failing at quoting the original post and link, I will edit this to fix that later if I can.) Anyways, this is also what I see in/under my roof. What I can't tell is how these steel beams attach to the sides. Best I can make out, they do. I am also interested in the structure of the roof and sidewall connection. My roof has additional 3" square aluminum bracing above where the 1x3 wood beams went. My wood beams though do not go side to side. But they appear to have been replaced with pressure treated wood sometime recently. Obviously, I need to replace these. I haven't decided what to do about the rusty steel beams, but one is sagging and attempts to rebend it back up don't seem to be very promising. I am likely going to need to replace this one. But if it is welded to the sidewall structure... My interior isn't gutted. The ceiling is mostly out up to the outer aluminum skin, but the walls are intact. The cupboards are out at least. The wood up in the wall to roof transition/joint is mostly gone, and what is still there has to be replaced. So I am trying to figure out how that portion was built, and come up with a suitable plan of attack. I plan on welding up a steel support framework for the AC unit. I will probably rivet it in from above, I don't want to weld anything inside if I can help it. I can see 3 steel beams. Two, while crappy, can probably be left in and just rust converted and sealed. But that third sagging one is where the steel AC framework would need to attached too and really needs to be replaced. I don't like the idea of steel touching aluminum, something needs to be done about that. But I also don't think I could get away with aluminum square tube structure. I don't have a simple way to weld it, and 3/4" aluminum tube is too flexible compared to steel. Quote Link to comment Share on other sites More sharing options...
WME Posted August 11, 2022 Share Posted August 11, 2022 You may have to dig up another coffee can from the back yard. But do you think a 3d x-ray attachment for your cell phone might be useful. https://walabot.com/ Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted August 11, 2022 Author Share Posted August 11, 2022 Maybe, if what was there was still intact…. Or original. And pretty sure that won’t tell me if the top and sides were welded together or not. I have wanted an excuse to get one of those though! It is pretty impressive tech. Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted September 4, 2022 Author Share Posted September 4, 2022 So this goes hand in hand with repairing the roof, just on the opposite side of the skin... I have more leaks, this time one is above the inside steel cross braces. Those are rusted so badly, they HAVE to be removed. I still haven't figured out how they are actually attached on the sides, but more , Are these steel cross beams even really NEEDED??? Dissimilar metals and all that could be causing half of my issues or more. I want these repairs to last another 30+ years (with proper roof care/protection). I can easily replace them with wood, since I have the 3" aluminum beams on the topside to attach too. I could use aluminum, but realistically 3/4" tube probably isn't worth the money for the strength provided. Especially if I have to drill 3/8" holes for the securing bolts. I need a support frame for the AC unit. I can probably get aluminum welded up at work, but here I am kinda leaning towards risking dissimilar metals and using steel, I KNOW this is quickly doable at my shop. And in fact I have a welder (just broken at the moment) that I could probably do this myself too. My boss is an awesome welder though, and I am not so I will probably just take it in ready to weld up. Google provides some simple enough answers for solving the aluminum against steel issue. Whatever, I am rambling. Aluminum might still be the better choice for this. It should be strong enough to support the AC unit. And it will be easier to attach safely on the sides too. But I defiantly need some advice and direction. Steel vs aluminum vs an easy wood solution for the interior braces. Wood I can sandwich and attach to the upper support beams easily. And next would be the support bracing for an AC unit. Again steel vs aluminum framework, or even a simpler wood option again? I could easily use 3/4 multilayer plywood (probably have the good stuff on hand too). Quote Link to comment Share on other sites More sharing options...
linda s Posted September 4, 2022 Share Posted September 4, 2022 Here's a complete Mini Cruiser rebuild. Major job but good pics of the roof bracing and maybe something you can use. Linda S Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted September 4, 2022 Author Share Posted September 4, 2022 (edited) WOW that is EXACTLY what I was after for some really good details!!! Thank you Linda! I am reading through it now!!! Humm I need to go grab a Kreg jig thing too... I like seeing how he tacked the framework inside. Edited September 4, 2022 by thewanderlustking Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted September 5, 2022 Author Share Posted September 5, 2022 THAT WAS PERFECT! I just spent some more time studying those pictures and while I suspect he didn't exactly copy factory (for one the steel beams are gone) it gives me plenty of ideas. And reassurance that in the end it probably doesn't really matter. Secure is secure! I don't want to open the sardine can though like he did... I am torn. The aluminum braces on top of my roof I am sure contribute to turbulence and poor fuel economy (but so do my solar panels). Still, having them up there means I can actually get up on my roof to clean off the panels and do whatever else is needed up there. I am noticing though that most people no longer even have the ladder. Mine is in need of some bracing inside where it attaches in the middle, so I can see why most would simply remove it instead of fixing that... I think if I were to peel the whole top off, I might do away with all of that and also the ladder. Those braces though will let me quickly redo the ceiling braces without peeling the roof off. They also give me some additional support for the solar panels. I didn't like how my panels were screwed down to the roof. My big one is now hinged off one of those braces and the other two smaller ones are also being reattached to the cross beams. Well todays project is to finish up what I can on the exhaust (waiting for some more parts) and tackle some more roof cleanup and removing those used steel beams... Going to try cutting one in the middle and see if I can then carefully wiggle it off and out. Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted October 15, 2022 Author Share Posted October 15, 2022 (edited) Okay the steel beams are cut out and the initial cleanup is done. I need to do some more, but I have a fair idea what I am working with now and how I am proceeding. I have covered some of this in the Roof HELP! Other than setting this on fire, any other more realistic options? thread as I was working through the ideas. But I have a pretty complete plan worked out now. The PLAN!: PS PLEASE critique this! Any "Thats a bad idea, try this" or "Do this here instead" kinda thing will be greatly appreciated!!! 1) Underneath the aluminum roof braces, I am going to put in Oak beams. While NOT CHEAP, I work with oak a lot and have plenty of woodworking tools to tackle anything there. It is also the wood of choice in wet environments and is commonly used for boat frames. HIGHLY rot resistant. I had an issue spending that much for something that would be covered up though, so I have a solution in step 4! 2) I need to add in at least a little bit of bow to the roof. This part of the plan isn't fully "formed" yet... I need to make up at least two beams. Possibly three. Later I might have a fourth beam in the back. I have a hot steam generator from Rockler Woodworking for bending planks. I will need to make a much larger steam box, but that isn't a big deal to do. Where the "unformed part" is, if I will try to bend a single 1" plank, or if I will plane them down and use three per beam, then laminate them together. I am usually working with really thin materials 1/32' to maybe 1/8" tops. I have maybe done 1/2" plank bends. Cost wise, I am paying for 1" boards for every plank used. My bandsaw isn't good enough to split 1" into two 1/2" boards, so I am running them through my planer. I probably could do it on the tablesaw, but not the safest thing to pull off... Most of my woodworking stuff is high end homeowners to lower end contractors grade. Not professional woodworkers grade. I am usually building small woodworking crafts with my favorite thing being vintage style RC Sailboats and pond yachts. 3) These planks will be bolted up to the roof with carriage bolts up and through the aluminum braces above. For looks, I might go with brass. I would prefer stronger steel ones, but if I put 5 in each beam I am sure brass is going to be strong enough. And above, I can EASILY solder/braze the nuts on before sealing with the roof coat. I will get back to this though... I have an inch to comfortably work with for the interior roof thickness. With flip flops on I can stand up straight and there is about 1/4" of room in most spots. If I bow the ceiling up in the middle some, I will gain that room too. In the back I do need to slouch ever so slightly, but it is a comfortable height. Moving on... 4) The beams are going to be visible and exposed. And I will utilize the lamination aspect to attach the ceiling panels. The main portion of the beam will be 1" thick. This could possibly be done as one piece. Or 2-3 laminated/glued together. If I do it as one, I will HAVE to steam bend it for sure. This will likely come to 1' total whatever the case. (I do need to go double check this and see if that's how thick the current beams are...) Next, the visible beam will have a recess routed into the backside the thickness of the PVC panel. Not sure how thick I will make this beam, but it will be slightly proud and will need the edged rounded over. I can probably go 1/2". Here is where we go back to step 3.... If I am going to have the carriage bolts going all the way through this final board, then they will be visible and brass would look nicer. I am leaning more towards having them slightly recessed into the board above, and then attaching this final board with some other method, like pocket screws. This is probably the better plan as it will let me remove a ceiling panel without getting on the roof and having to recoat the spots afterwards. 5) I want things tight enough that the final PVC panel is held up just on the edges and with the recesses cut into the last beam "cap". I think the spans are only about 3' between the beams, so this should be doable. Again this allows me quick access to dropping the panels. Allowing running thin wires for lights, or stuff like that later on. And heaven forbid, leak tracing. 6) I will need to make a simple form to get repeatable consistency. I think I am going to try and go for an inch in the middle. 2-3pcs of 2x4 or 2x6 stacked, clamped, and cut should work nicely for this. And also let me do the same for any additional frames I need to make up like for the AC support. These materials are not going to be cheap. Especially the oak... But I need to redo some other things in there like the dining benches. Oak for those frames will be super strong, but since I am only doing the outer framework and using the PVC panels for the inset parts, it should work out to be stronger than the original, and almost as light. If I made the WHOLE thing out of oak, yeah I don't want that bill for materials OR the weight... I would like to use oak elsewhere too inside. Refacing the kitchen drawers, perhaps the closet door. Shelf edges. But I have to balance out the budget at some point. Not just money and weight, but also time. I think for anything I have to redo anyways, it might make sense. Sparingly used for accents, or anyplace I need moisture protection and strength. The materials for the beams are sitting in my cart. The first round is about $500. I should have a good amount left over for the other stuff. And I already have a good stockpile of oak on hand to begin with, just nothing long enough for the beams. I can use other materials for the beams, but I am thinking if I want to add that bow in, make it stay together and last, and KEEP the bow, that laminating the oak is going to be the trick. Edited October 15, 2022 by thewanderlustking Quote Link to comment Share on other sites More sharing options...
extech Posted October 15, 2022 Share Posted October 15, 2022 have you considered just making a peak in the roof? seems a lot simpler Quote Link to comment Share on other sites More sharing options...
linda s Posted October 15, 2022 Share Posted October 15, 2022 No curve is possible with those horrible aluminum beams on the roof. They not only look bad they are in the way of properly fixing the roof. Linda S Quote Link to comment Share on other sites More sharing options...
WME Posted October 16, 2022 Share Posted October 16, 2022 With winter coming on, I'm sure it will be to cold to work outside🤪. So some lite reading... "Nida-core" and End Grain Balsa carbon fiber panels Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted October 16, 2022 Author Share Posted October 16, 2022 5 hours ago, extech said: have you considered just making a peak in the roof? seems a lot simpler That is kinda what had been tried by the P.I., and then I added to it with the dam I made... Didn't work well on top of the existing junk. To do this effectively from the outside, I would either need to utilize the "cover it in spray foam and carve it off" trick, or probably more realistically, rip the roof off and start over. There are other approaches that could made sense, but either I create a lot more seams for water to get in, or I remove the aluminum beams. And doing that would probably require reskinning the roof afterwards. 5 hours ago, linda s said: No curve is possible with those horrible aluminum beams on the roof. They not only look bad they are in the way of properly fixing the roof. Linda S This is something I need to explore a little closer and give some more thought... A little while back you warned me about putting pressure on the roof, using a ladder on the side etc, etc. Because of those beams, I had never worried about actually getting up on TOP of the roof, but I was paying much closer attention the next time I did. I am not small and light, lol. But as long as I put my weight over the beams, they are SUPER sturdy. I have long considered putting a few planks down for a sort of catwalk like platform. Anyways when I got up on there, I did notice a small amount of downward deflection on the beams. Hard to say how much, but enough I could actually see it. Anyways since that point, I have wondered if it was still just enough flex to cause the panel seam right in front of the second one to split open. So I have stopped going onto the roof and crawling about up there, and just use a ladder leaned up on the side. I think I can probably get between 3/8ths to 3/4" of upward bow. I am sure I can get at least enough to get it eliminate any low areas for water to pool. And for sure, they are ugly and removing hem would look WAY nicer. But I am fairly sure doing so would also damage the roof way more than just leaving them alone. At best, I will have the holes to fill up. Plus, they give some sort of structure to mount solar panels to that doesn't put holes through the roof, or odd little glue on mounts. I will take a closer look in the light and take some measurements. I can clean them up a touch more too and eliminate the end plugs that make them look like railings stolen from somewhere... Quote Link to comment Share on other sites More sharing options...
WME Posted October 18, 2022 Share Posted October 18, 2022 IF you could carefully remove the beams, you can use a chain and a bottle jack to bend them (think bow and arrow). Then reinstall them and bolt through the roof and pull up the center. Like you said 3/4" would do a lot of good. Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted October 20, 2022 Author Share Posted October 20, 2022 I’m torn on that…. If I can safely get them off the roof, I probably would eliminate them all together like Linda suggests. While not as bad as the AC unit was, they are still on there pretty good. But I think I’m going to try a slight variation of your idea. Going to secure the ends, and gently use a jack/pole in the middle. But first, I have a couple other small jobs to finish. Need to access the sides, order supplies, and clean up the roof. It is currently decorated for Halloween too, so not in a big hurry. It might also be I already have enough flex in them to just get away with curving the underside beams then secure it it all. Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted October 30, 2022 Author Share Posted October 30, 2022 (edited) Any further opinions and thoughts on the wood to use for the bracing/beams??? My plan has been to use oak... I am still thinking oak is the best choice. But I got "sideswiped" lol. I have had the materials sitting in my Amazon cart the last two weeks, but hadn't pulled the trigger yet. I had a 4 pack 1x6x72 and a 6 pack 1x4x72. But I just got over having a DURR moment and realized that 72" is only 6'... Sure enough, she is just short of 7' wide. I need at least 80". So 84" or even 96" for a standard stock length. I am not scarfing boards to do this... WAY TOO much work, I would need to laminate in two directions. Amazon wasn't the cheapest option, but it was by far the simplest. And I almost have enough gift cards and bonus points to cover the full amount. I still need a couple random tools though, so it will go towards the project. If I am going to try and introduce more than about 1/4" curve into the beams, I will need to either laminate three 1/4-3/8 pieces together, or make a form and steam end them. Either way, I probably need to use a form. For steam, I need to make a bigger box. But for laminating them, I need to plane the 1' down to the final thickness. So probably about the same amount of work either way. Except the steaming option leaves me with another tool for the collection... And that is a LOT of hard work for my little 13" Delta planer. So two decisions to make: 1) Stick with oak? Or something else also readily available? Oak is super strong, and EXTREMELY rot resistant. Realistically, it might be the only option strong enough if there is any serious thought to removing those aluminum beams on top. I really have no plan to do so though, and I guess that could open up my options. I can seal anything else I use with my favorite Z-Poxy PT-40 slightly thinned with denatured alcohol. 2) Steam bend solid 3/4-1" board for the main beam? Or laminate 3 layers? Either option, oak or not, will get a lower oak capstrip that I will use to hold the panels up. This is really the last construction detail I am kinda stuck on. I have a pretty solid plan for everything else with only minor choices to still decide on. Other than the bathroom... But that is probably next years project. I want to get a season of use in before tackling that, other than a quick sorting and replacing of missing/damaged stuff. Edited October 30, 2022 by thewanderlustking Quote Link to comment Share on other sites More sharing options...
linda s Posted October 30, 2022 Share Posted October 30, 2022 Roof beam instructions you can complete without fancy tools or steaming wood MATERIALS: One good quality straight grained red fir or spruce 2x4 8 ft long (or equivalent), with no large knots, 8 ft of 1 1/2" by 1/8" steel bar, primed and painted, Two 5/16" by 3" lag bolts with wide area flat washers (fender washers), several #10 by 1" wood screws, construction adhesive, and silicone caulk to seal outside when done. Make a cardboard or paper pattern of the curvature of the roof where it is best preserved, usually at the front or rear where sagging has not occurred. Trim the 2x4 to fit snug from wall to wall then trim another 1/4 " off one end. Next transfer the pattern to one edge of the 2x4 and saw the curve on a band saw so that you get an even cut. Cut the metal strap to a length that will allow full coverage of the curved edge of the 2x4 plus bending over both ends. Drill 3/16" holes every 12" or so in the strap and countersink each hole so that the heads of your wood screws will be flush when installed. Form the metal strap to the shape of the wood piece and bend it down over the ends for a tight fit. Do a trial fit to the motor home and adjust as needed. Mark the strap at the center of each end of the truss and drill a 5/16" hole at each of these marks through the metal only. These holes will be the anchor points for the ends of the truss. Now run a bead of construction adhesive along the curved edge of the board and install the strap with wood screws making sure everything is properly aligned as you go. Next, drill a 1/4" pilot hole into the wood at each end where the previously drilled larger holes are located. Apply construction adhesive to the top of the truss and raise it into position inside the roof at desired location. You may need to force it up with bracing between the floor and the truss to get it into position. Measure the distance from a reference point on the motor home to the center line of the truss on each side of the vehicle. Next drill a 1/8" pilot hole from the outside through the fiberglass at each point making sure these holes coincide with the holes in the end of the truss. Once that is established you can drill the pilot hole out to 5/16" to install the lag bolts. Use rubber gaskets or sealant under the flat washers. Also cover the bolt heads with sealant or other waterproof cover. Now you can install upholstery and modify your upper cabinets to accommodate the truss. Linda S Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted October 30, 2022 Author Share Posted October 30, 2022 Linda, I probably can't count the times you have told me "simpler is better" and that I shouldn't overthink things. This kept replaying in my head as I was poking about and brainstorming my options today. I have been out there measuring, inspecting, and exploring in there for a few hours now. In fact as I worked through ideas, this mantra made me revamp some of my other plans too. Simplify, simplify, simplify. In the end getting to actually USE it before getting burnt out on the build, is more important than perfecting every little detail. Staring at things closely and taking lots and lots of measurements, I realized I will have to use 4 beams instead of 3 over the main area. Once I have those 4, it might look a little odd. Unless I continue this and add another 3 beams, 2 in the front and 1 behind it. The current beams inside are 3/4" thick. Spacing between is 21", and they are 3 1/2" wide. Some still have about 1/8" worth of paneling attached. If I don't want to be hunched over, I only have 1/2" left with flip flops on. This translates to I have enough room for 3/4" thick beams, 1/8" paneling, and 1/4" cap/finishing strips. There is no curvature on the original roof sections. Or at least in the back half where it is still original and intact, and also not leaking. In the time I have had it, it has never leaked back there. (Other than the one spot right on the border where I stopped with the reseal coating, and that only leaked during the hurricane) This makes me rethink the bracing plan... My driveway has 2.5 degrees of side to side, and almost 4 degrees front to back according to a bubble level on the floor. It will never be parked long term in a flat spot... I think curving the roof period is probably overthinking and over complicating it... Simplest approach would be just to take extra care, get enough support structure (the 4 beams alone will do this) to get the roof level and straight again without any dips. In all seriousness, I can recoat the roof 2x3 times with the Henry 887 I still have on hand. I plan on using up all or at least most of what I have on hand anyways. If I have to redo this again in 3-4yrs, it will still will be way less effort and expense. ` Quote Link to comment Share on other sites More sharing options...
WME Posted October 30, 2022 Share Posted October 30, 2022 On my Escaper I used 2 banister rails to lift the roof. Depends on where your counter tops are. But I jacked up the roof and cut the rails to fit, a dab of construction adhesive. Lowered the jack and the rails never moved. I ended up with a 1/2" crown. Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted October 31, 2022 Author Share Posted October 31, 2022 (edited) Give me a few and I will describe the picture lol.... EDIT: UGH I just lost the whole explanation post. Edited October 31, 2022 by thewanderlustking Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted October 31, 2022 Author Share Posted October 31, 2022 Well thats an issue.... I have been trying this laptop out on Linux, specifically Ubuntu. Apparently, I can only undo one step back in Firefox Unfortunately, a single step back is just one letter typed too. Overall it is awesome, but for some reason it likes to jump now and then and scramble typing order. Like you will type 1234567890 but it comes out 12389045 and overwrites 67... My Macbook on Safari can easily go back multiple steps. I was about to post and was typing the last sentence when it jumped, selected the whole post, and overwrite it with dd. So my one undo, left me with just a "d". D for damn... I will have to try and sort that out. Yeah usually I can quickly hit the back back button, hit respond and it remembers what I had typed in. For some reason Firefox dumped the text editor. Quote Link to comment Share on other sites More sharing options...
thewanderlustking Posted October 31, 2022 Author Share Posted October 31, 2022 Let’s try this again lol! The PO had done something similar to your suggestion WME, he even used a bannister railing! It was going front to back and was maybe 5’ long. It was a t-style rail, so it should have been really strong, but it was bowed down something crazy like 3”… The picture is taken with me leaning against the kitchen counter in the back. The back wall is half the kitchen stove and sink on the passenger side and the other half is the bathroom. Point mainly being that I don’t have any good places to use for support columns. The dark column going up on the middle/right not attached to anything at the top, was the rear support for this beam. It is attached to the rear seat back about 3” in from the aisle edge. There was another same spot on the front seat. It made getting in and out of the upper bunk really difficult though. The upper cabinets on both sides were removed. It feels MUCH more open in there without them! And combined with the support column, they made it impossible for me to get in the upper bunk. I did manage to save the ones above the couch. I could probably reinstall them and still be okay to climb up in the bunk. But besides simply clogging up the space, I can’t think of any likely use scenarios where I am going to need the additional storage enough to sacrifice that openness. That is all a discusión for somewhere else though. For now, the cabinets are removed and out of the way of making ceiling repairs. I am definitely leaning towards simpler. With some basic, straight 3/4” oak beams, I can take out all the sag, have something thick enough to safely attach with pocket holes, but still thin enough I can stand up inside, and it is almost completely rot proof. Spruce would work well too, if I had the additional height to sacrifice. It is a softwood. I would have to either laminate it, or use it at double the thickness of the oak. BUT I’m really stoked that Linda mentioned spruce! I hadn’t thought of utilizing it. It is cheap, readily available, very rot resistant, light, and super easy to work with. It is PERFECT for repairing and building out other stuff inside. In fact, I’m going to use spruce instead of recycled pallet wood for my counters and tabletop. While not free, cost will be minimal and greatly simplify the construction. No metal detector and additional processing needed. Win win! Quote Link to comment Share on other sites More sharing options...
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