Teardrops n Tiny Travel Trailers

Yes, I know this is going to sound nuts! I am wondering if anyone has ever used steel siding for their teardrops or other travel trailers for a skin? I realize it is about 2.5 times as dense than aluminum, but thin gauge would hold up better against rocks, hail, and such when compared to aluminum. It appears to be much cheaper per sq. ft. I can get it in about 20 different colors, all with a 40 year warranty. It is 29 gauge and they want about $3.12 per linear foot at 40 7/8 inch wide. It is local, and they can do any length up far beyond what I could ever need.

I know seams would be a issue, I would end up with seams either vertically or horizontally. Is there a way to seal the seams? I have a enclosed cargo trailer I rebuilt the frame for, not sure what they used for the sides but a magnet won't stick to it. I assume aluminum also. They used vertical seams, with the front pieces on last, and the first one on were the rear. The end of each panel, over lapping about 2-3 inches. I never seen any leaking of any kind at the seams. Has anyone used used a method of sealing seams on a roof that is wider than normal? My roof currently is looking at about 6' to 6'6" wide.

I know it will be heavier long run, but I am also pulling with a 3/4 ton truck, my idea is based on a gooseneck trailer design. Thanks! - James

Are you thinking in terms of a 40" wide flat sheet or will it have a profile or ribs like corrugated, r panels, or v crimps?

I used steel exclusively on two of my trailer exteriors and for trim on two others.

My siding is roll formed, one in a faux log profile, the other in a board and batten pattern. I also made standing seam roofs for both.

Joints, seams, trim, etc. can be problematic depending on your design but overcoming with proper techniques and flashing will solve all.

Most trailer manufacturers using flat sheet just lap joints with sealant between then rivet or screw. Others use VHB tape to seal and join the sheets and attach to structural members.

You need to have and know how to use a metal brake to do it the right way. Just my opinion.

M C

Personally I have not seen it done, but I did google it and see the color choices which makes it interesting...

However, 29ga is 0.0135" thick which is 3 times thinner than the light weight .030 aluminum that every one uses. I dont see how that would be any stronger or handle rocks better. Seems like it would show dents, bumps, scratches much more and still be susceptible to rusting.

I have a 1952 Vagabond that has steel siding on it (see the rust?)
There was a shortage of aluminum during the Korean War so they had to find an alternative.

Thanks for the reply guys!

M C Toyer, yes to the 40" wide flat sheet. The place does metal buildings, sidings and roof systems. The have gigantic rolls of the material that are about 40 7/8" wide. Then have a system of rollers/dies they use to form the profiles they use, along with equipment for sheering, bending, etc. The can normally do average size order turn around in 24 hrs. For something as small as I am doing, less than 12 hrs for the order, but with custom work, up to 24 hrs. I think I would go flat, as the sheets could also be bent over curves, I think once a profile is added, you can only bend in one direction at that point. I was thinking much like lap joints, but not sure how else to seal it up. The roof would be the challenge at 6' to 6'6" wide. I guess I am not sure what VHB tape is, or how it is used to join the sheets. Sounds interesting. I have access to a 48" manual brake that can do up to 22 gauge. Please share anything else you know!

Vegask, correct about the gauge. The supplier told me their sheeting product runs on the thicker side, closer to 28 gauge sometimes closer to .0150". Even at .0135", you have to remember steel is stronger than aluminum. It is more dense. From what I have read, about 2.5 times (do correct me if I am wrong). If I am not mistaken, .0135 x 2.5 = .03375" Denser materials are less likely to dent. Aluminum is a much softer metal. Yes, you are right, rust can be an issue. I am sure with a 40 year warranty on the finish, their expertise on installation I can assume little rust issues. Aluminum does have issues with corrosion, I have seen a aluminum trailer fall victim to a nasty onset of it. Aluminum is also very expensive, dents easy, scratches easily, and is much harder to repair. To me, the cost alone doesn't make me think the weight savings is worth it.

Irmo Atomics, that is a very lovely vintage trailer. She looks pretty sexy for her age! Rust, nah, that is just patina finish! She might have rust, but given she is about 64 years old, I would say that it has aged pretty well. How does she pull and how is she holding up? Great picture.

Thanks all for the replies, I hope to more back, you people are great! - James

Vajra wrote:Thanks for the reply guys!

M C Toyer, yes to the 40" wide flat sheet. The place does metal buildings, sidings and roof systems. The have gigantic rolls of the material that are about 40 7/8" wide. Then have a system of rollers/dies they use to form the profiles they use, along with equipment for sheering, bending, etc. The can normally do average size order turn around in 24 hrs. For something as small as I am doing, less than 12 hrs for the order, but with custom work, up to 24 hrs. I think I would go flat, as the sheets could also be bent over curves, I think once a profile is added, you can only bend in one direction at that point. I was thinking much like lap joints, but not sure how else to seal it up. The roof would be the challenge at 6' to 6'6" wide. I guess I am not sure what VHB tape is, or how it is used to join the sheets. Sounds interesting. I have access to a 48" manual brake that can do up to 22 gauge. Please share anything else you know!

Vegask, correct about the gauge. The supplier told me their sheeting product runs on the thicker side, closer to 28 gauge sometimes closer to .0150". Even at .0135", you have to remember steel is stronger than aluminum. It is more dense. From what I have read, about 2.5 times (do correct me if I am wrong). If I am not mistaken, .0135 x 2.5 = .03375" Denser materials are less likely to dent. Aluminum is a much softer metal. Yes, you are right, rust can be an issue. I am sure with a 40 year warranty on the finish, their expertise on installation I can assume little rust issues. Aluminum does have issues with corrosion, I have seen a aluminum trailer fall victim to a nasty onset of it. Aluminum is also very expensive, dents easy, scratches easily, and is much harder to repair. To me, the cost alone doesn't make me think the weight savings is worth it.

Irmo Atomics, that is a very lovely vintage trailer. She looks pretty sexy for her age! Rust, nah, that is just patina finish! She might have rust, but given she is about 64 years old, I would say that it has aged pretty well. How does she pull and how is she holding up? Great picture.

Thanks all for the replies, I hope to more back, you people are great! - James

Check out VHB tape here.
http://solutions.3m.com/wps/portal/3M/e ... 3694603433
I used it on aluminum panel to steel post and on inside wood panel to steel post.

Jim

Sheet steel of the same weight per sq ft will be more likely to be damaged by hail or stones than sheet aluminium, since it will be thinner. Thickness matters more than the strength of the material. That some vehicles are not damaged by hail or stones will be because they have thick steel, not because they are steel.

I bet that any coating/rust warranty won't apply to the cut edges (or possibly any edges) of pre-painted sheets and you aren't going to use only whole sheets skinning a teardrop. The Vagabond photo below shows no rust in the middle of panels (except maybe where damage occurred) and the rust is concentrated at panel edges. So finding out what edge preparation is possible, or is required to maintain the warranty, would be an important first step before thinking of using sheet steel.

Any holes or openings cut through the sheet steel will attract the same problem as cut edges.

Thanks for the link Corncountry, that is some interesting stuff. The show some smooth sides where I don't see lap seams. I wonder if they do butt joints with the tape? This looks like it would be very good throughout the construction. I am looking at a few different wall options. From skinning plywood, to more of a enclosed cargo trailer style wall, where the panels are attached on the studs/posts. My walls are looking to be about 3.5 inches thick minimum. Why so thick, extra insulation. Gets cold here during winter and I still plan on using it. Might not to the full thickness, but the 2x4 and 2x6 framing would allow it. Sounds like over kill to most, I have my reasons though!

Angib, I wasn't looking at weight as being a factor so much. If you have .0150 Aluminum verses .0150 Steel sheet, I think you'd find that Aluminum, being much softer, will not resist a damage by stones or hail as well as the steel will. Steel is much more abrasion resistant for the same thickness. My thinking was that the steel sheeting, while thinner, won't be that much different from what the .030 aluminum has to offer as far as denting. Weight isn't a issue, as I am using a 2500 to pull it, can't believe my 6' x 6.5' x 16' design would ever hit 11K pounds...

When I contacted the retailer about their product, one of the first few things was in fact about the issue of rust. This place is well known for it's abilities, they have done some seriously large buildings of all kinds and needs. I was concerned also about any spot that is cut, or had a hole. They told me that the coatings they use, help prevent that rust, and with (like the other person mentioned) proper perpetration that rust shouldn't be that much of a issue, that the skin should require no more maintenance then anything else. The gentleman said if I follow their instructions and recommendations, they will back up their warranty without issue. They do have special fasteners that help seal any holes made. I explained my design to them, and they suggested 6 sheets for the main body. So yes, full sheets except for the cut outs. They have the ability to do cut outs to ensure good fitting. I have seen one of their buildings roof and siding that is a bit old, I think 15 years or so, and it was in a area that got blasted with hail once. I see no hints of dents or damage. No rusting. I won't just dive in, so far, they have been very helpful. Aluminum is just very costly, and it too, has some issues. Everything I am looking at so far, steel is about a 1/3 of the cost. There are other options, this is just one of the cheapest I can find locally. A steel panel as mentioned at about .0150 is about 40.875" x 144" for around 37.44. The closest I could find to was .032 aluminum in 48" x 144" was 141.54 per sheet... So yeah... them pennies.

Vajra -

Re the potential for rust with the steel siding, I am assuming the steel will be galvanized or a similar process before painting, thus they are able to offer a 40 year guarantee, prorated no doubt. The concern for the uncoated edge is valid but you can minimize the exposure by hemming (i.e., folding 3/4" 180 degrees flat with the painted side out) all raw edges and use a grooved/offset flat lock seam to join the panels with sealant applied to the pockets.

Also all cuts should be sheared, not sawn and all holes punched, not drilled. Heat from saws and drills will damage the base metal, coatings and the paint and hasten rust in that area.

You said it will be a gooseneck design approximately 16' L x 6-1/2' W. Will the roof be flat and the walls straight? If you use a simple lap joint (which I DO NOT recommend) the steel sheets can be rolled over a matching substrate with tight radius. If it has a flat lock seam you can make a gentle bow in the length but the width can be rolled. You can purchase preformed rounded corners, corner-caps, a nose-cap if you desire that shape.

With your trailer size the sidewall panels would need to be mounted vertically and across the roof, not lengthwise. Regardless of type of joint you want the panel seams to overlap so the outer edge of the seam is away from the direction of travel, i.e., start at the rear of the trailer and work to the front. On a forward facing wall start on the sides and work toward the center.

I would not recommend a butt joint under any circumstance. Have you ever tried to hang wallpaper? If you use a simple lap joint with the VHB tape you won't necessarily need any fasteners. With a simple lap joint and putty tape or similar sealant you will need external fasteners fairly close together to secure the joint and hold the panels to the substrate. If you do not hem the overlapping panel you will not get a tight joint no matter how many fasteners you use. I'm sure the supplier is recommending zip or self tapping screws with neoprene washers, but waterproof rivets are available. Neither are foolproof unless properly seated and torqued, especially on a roof.

If you use a flat lock seam you will not need any external fasteners. The forward edge of the underlying panel can be held to the substrate/studs with a cleat or tab. I would strongly recommend spacing the studs to match so the joints are directly on top, whichever style you use.

The larger concern, in my opinion, is the 29 gauge panels, if they do not have some rolled linear reinforcing ribs. The ribs would not need to be any higher than about 1/8" and could be spaced so they match the flat lock joint. Even with the ribs the 29 gauge may billow slightly at high speed. You will need to be careful handling the panels - a bend or kink will cause a crease that cant be hidden. Commercial grade metal roofing is a minimum 26 gauge and less likely to have this issue. You might want to buy a small amount of the material and practice before committing. Maybe just build a small storage box.

You also need to turn the bottom edge of the sidewall panels under and around the bottom of the substrate or a flat starter piece. Angle trim, properly seated with putty tape or VHB tape, will seal the roof to the side walls but you may have to double in the valleys between the ribs and seams.

Re VHB tape, it is expensive and you only get one try to position and attached the panel. You will likely ruin both the steel panel and VHB is you try to remove them. A non-hardening sealant will allow you to make adjustments and also accommodate some expansion of the panels and flexing of the trailer.

I believe you said you will be sheathing the exterior with plywood or OSB. You might want to consider using fiberglass faced wood sheathing and taping the joints as prescribed and/or using a vapor barrier wrap like Tyvek.

The hems and flat lock joints with 29 gauge can be formed with a portable metal brake. You need an 8' model but 10" and 12" are common standard sizes. You should be able to find a rental. The 4' you have access to will be great for the bottom wrap - you will just have to trim part of the seam lock.

29 gauge steel weighs about 90# per 100 square feet. If you were to use aluminum instead of steel I would recommend the very same procedures.

Thanks M C Toyer for the information and insight. I haven't had a chance to call them back or go there, I hope to either Friday or next week when time permits. I've had a busy week getting all ready for my next round of college classes this coming week.

Hemming was something also brought up by a co-worker of mine. I will look into that! I was also planning on using some form of protection on the edges, before installing. I know someone at my shop used either bedliner or something similar on the bare edges about a 1/2 or so, then folded them over. I haven't had a chance to ask him due to the difference in shifts. I did plan to use a sealant on the under inside corners to help keep water out and other road spray out as much as possible.

I'll do my best with the issues of sawing and drilling. They said they can make and brake/sheer to what I need, so hopefully that will help. I do have a hole punch, well, a set of them actually.

Yes, about right for the gooseneck. I understand people are probably already thinking, "He has to be crazy." But, my reasons behind what I am trying to do, covers a lot of areas. The sides and roof would all have some curve to them. If you will, imagine a V-nose trailer. Only, the V would be more of a bullet shape, to a full width, and the last 4 feet or so, tapering inward towards the back to reduce drag. The roof would also go from the gooseneck, incline to about 1/3 the way of the main body, then the other 2/3 slope down by about a foot. I figured this would help shed water. However, I am concerned about the front incline slope, and where the skin attaches, damming up with water standing on the seam. If I go the other way with the roofing, I feel the water or air hitting the seam would degrade the seam/sealant and allow penetration. I have considered over lapping the roof with a rubber roofing to help reduce this issue. BTW, yes, I have indeed thought that a seam should never face forward. The reason we talking about lengthwise, was if it is thew best option. Which I doubt, but it could be done. He said it is possible to do a bottom sheet, then top sheet, with a mid-center lap joint. All water would shed downwards. The roof could have a slight peak, with a center trim cap that would act like a house. I also realize, this would be harder to make. I have thought about other design changes, but I don't know that I will go that route, even if cool or unique.

Yeah, I wouldn't do a butt joint, unless there was a special covering to go over the seam. I would think this would be weak, and not so well holding in the long run. I was thinking a simple lap joint, with VHB tape, if it really is that good. They did recommend some special screws, and they come in matching color. They also suggested rivets and that sealants should be used to help keep those areas sealed in my case. I didn't know about the flat lock seam until I read your post. However today at work, I did take down a exhaust hood that used a series of folds like you mention. Not a single fastener, very strong. I will have to inquire about that. Would I need the rib reinforcement if I use plywood walls? Could I not use extra tape, say center of the two edges? I was considering using Tyvek on the plywood, though I am not sure how well it would work with the VHB tape... never recall seeing a fiberglass faced wood sheathing. Going to have to go see some.

I'll have to do some more research and look more deeply into things, be giving the company a call to inquire more about their products, perhaps pick up a sample to work with. Thanks for all the input! - James

James -

You've got a good handle in the basics.

My thoughts about running the roof panels crossways was based on the practical length using the flat lock seam and ease of handling. Also each panel will be secured on the ends by the angle trim over the sidewalls. Once you get beyond about 8 feet in length you will need helpers to keep the panel from kinking while installing.

Running the panels lengthways with the center overlapping the outer, especially if crowned, is workable if you really trust the VHB. I would avoid at all costs any screwed lap seams on the roof.

Puddling on the roof because of the height of the lock seam and the corresponding elevation of the edge trim can be avoided by eliminating the ribs and reversing the offset so the crown is on the panel bottom. You would just need to plow a groove in the substrate below the seam, or elevate the pans of the panels with material of comparable thickness. An alternative on a flat roof would be to reverse the seam and run the panels lengthways turning the outer edges 90 degrees over the sidewall thus eliminating the need for angle trim. Portable brakes are available up to 19 feet but the supplier likely has that capability and you would only three panels which they could do cheaper than a brake rental. In this scenario you would install the center panel first then the outer pair.

Another option for the roof, I am sure the supplier can form a standing lock seam which would be a good option if you decide to run lengthwise and not use VHB there.



The supplier can roll the ribs of you decide to go that way. They will likely have some fair size scraps of the flat material they will let you have to experiment with. They generally use the damaged/scratched ones for packing or just salvage the metal. They may also be able to roll the flat lock seams.

You will want to use offset aviation snips for shearing, trimming and cutouts. Sears' Midland brand are good - you will need both left and right anvil and are around $36 for the pair.



Only very small holes, say under 1/2", would need to be punched. From that size up to about 3" you can cut out with a chisel, and larger ones with the offset snips. In situations where you may need a screwed lap seam or face attaching accessories you will want a clean hole through both panels just slightly larger than the screw so the metal won't pucker and the joint will lay completely flat. Punching numerous small screw holes can be very labor intensive so a slow speed drill when using the neoprene washers is acceptable. Just put a dab of sealant in the holes before screwing down.

The fiberglass faced sheathing is essentially the same result as using Tyvek, just much easier.



A single sheet rubber membrane for the roof is good insurance but may present challenges with the VHB.

On the sidewall corners you can just bend the vertical panels 90 degrees or roll around a tight raidus rather than using a separate trim piece.

I'm not knowledgeable about the aerodynamics but others here are. Tapering the nose may present a better appearance but may not noticeably reduce the drag. It may require some compromise between aesthetics and waterproofing.

My trailer is not aerodynamic at all. The exterior is all steel and there are no exposed fasteners except for a couple on the vertical edge of the front fascia flashing as insurance against wind lift. The roof, ridge and flashing are all standing lock seams. The faux log siding panels are 14 feet in length and use a flat lock seam.



M C

At the bottom a schematic of a hand made (portable metal brake) standing seam metal roof. The machine made (roll formed) standing seam roofs generally have a crimp lock but the hand made isn't capable of the close tolerances to insure 90+ mph wind resistance.

The fascia boards had already been wrapped with a u-shape metal fascia nailed through the roof only. Not shown in the schematic is a waterproof membrane over the decking. I used "Roll-Flat" which is similar to standard roofing felt but has a fiberglass base. I used the 2' round tin roof caps with staples rather than the plastic button nail caps which protrude just enough to raise a bump when you step or kneel on the metal roof. The drip edge flashing on the hip has a 3/4" lip extending past the deck and is also nailed through the roof only.



My roof has about 2-1/2 : 12 slope. The 2 x 3 rafters are about 5' in length on each side and spaced 20" on center, primarily because I used 24" wide material for the pans.

The pans were formed with two inward bends on each side; the first 180 degree and the second 90 degrees. The resulting vertical legs are about 1-1/8" high because heavy snow is not an issue in my area. I started in the center of the roof and worked outward. I actually made the pans 10' long and clipped the legs in the center to fold over the ridge so there is not a seam there.

After the first pan is laid in place a cleat is placed over the vertical legs and secured to the decking and rafter. The cleat is similar to a pan leg except the second 90 degree bend is outward. Then another pan is placed next to the previous and a cleat on the opposite leg.

The pans extend 3/4" past the lip of the drip edge flashing. The pan legs are clipped flush with the flashing lip and the extra 3/4' of the pan bent 180 degrees around the lip to secure that edge.

The seam cap is formed similar to an inverted pan; 180 degree bends on the outer sides then two 90 degree bends for the squared crown. Mine is about 1/2" wide. It slides on from the hip to the ridge locking the pans together which are already secured to the deck and rafter. The caps overlap at the ridge where the legs were clipped and are pop riveted to them. They are left about 2" long at the hip then that end is partially clipped and folded back under its sides and the very bottom folded under the drip edge flashing like the pans were.

The final seam cap on each gable end has only a single 180 degrees bend but a slight flare to double as drip edge flashing.

The ridge cap is held in place with a hidden cleat which was pop riveted to the crown of the seam cap. It also has a closed cell rubber foam baffle between the cap and pans to deflect water infiltration but the ridge is watertight without the cap. The ends of the cap are folded down over the gable fascia.

The same procedures would work running lengthways on a flat roof with drip edge flashing on the ends but would be advisable to seal both ends of the caps where they fold back under their sides. I would also add an L shape cap at the front and rear extending about an 1-1/2" in both directions to deflect direct wind / water infiltration but with about 1/2" space to permit drainage and prevent clogging with dirt and leaves. With a flat roof the outer pans can be folded 90 degrees over the sidewalls eliminating a separate angle trim piece there. You would just make one standing leg, cut the pan width to cover the remaining roof plus the overhang plus a hem and slight flare.

Keep in mind that the front of a trailer can take considerable abuse from rock chips. I pull on miles of gravel roads every year and this is what my tongue box looks like:





It'd be a rusty bucket if it were made from painted steel.

Tony

Tony, thanks for the reminder. On my enclosed cargo trailer I rebuilt, I added diamond plate to the front. Even now it gets a beating. I have a nice set of rock slingers on my truck. I have plans to make a good amount of the front reinforced with materials that can take some serious abuse. How come you didn't use diamond plate or something more resistant on the tongue box?

MC, great looking trailer. The faux chimney is pretty cool. Thanks for the heads up on the snips. The rubber roofing, I was thinking would have mechanical fasteners, like a secondary roofing. The stuff doesn't seem to last, so I would want to be able to remove and replace it.

Aerodynamics isn't to hard to understand, just takes a hour or two of reading to get a pretty good idea of it. I know my idea seems nuts, but if I can get 1 MPG more while towing, that makes a great deal of difference. A extra 36 miles per tank may not seem like much, but long run it adds up. I plan on towing it a great deal, not just to a camp site on a weekend. Every little bit helps. I guess though, that it is looking less likely I can do a construction without having to give up waterproofing or aerodynamics. Thanks for all the info. I have much more research to do, along with calls. Didn't find any fiberglass faced sheathing at any of the big box stores. How do you seal up cut edges or edges that at 90 degrees to another? The tape they show on the seams?

Have to get going, lots to do today and this week is going to be hellish with college classes starting! Thanks for the responses.. -James

Joye wrote:It is a good idea for using steel sheets to prevent rocks and hail. The price of steel sheets is lower than aluminum. But aluminum is more durable and has stronger corrosion resistance. For steel color, you can choose all RAl colors according to your requirement.
About the seams, if you want a vertical seam, I suggest you use high-quality sealants of the waterproof, which can prevent chemical corrosion. Also, you can invite a professional engineer to help you seal the steel sliding. On the side of the frame, I also recommend you use aluminum to ensure longer service life.

You've done one post on a thread that's seven years old.