5x9 Hybrid

[TJinPgh]

So, while I'm still waiting to gather funds for a build, I've been looking around at various other designs and comparing them to the ones I've posted.

While I like the simplicity of the 6x8 box design I posted, I'm still not sure how I feel about the overall looks of it. Some of the others who would be using it had expressed some similar thoughts as well.

So, I thought I'd go back to the drawing board and come up with something that is (hopefully) not too difficult for a first build but maybe a little less boxish.

So, after a lot of searching and tweaking, I came up with this 5x9 unit that I suppose you could call a TD, though perhaps not a traditional one.

I'm thinking the weight could be kept down by doing it as a foam hybrid.



Not quite sure what to use for the roof skin. I'm thinking canvas covered 1/8" ply, though.



I still don't think I need a permanent galley. We all seemed to agree on that. So, this unit doesn't have a proper hatch, which eliminates the always difficult task of keeping one from leaking.



Still, it might be good to have an area that I can cook on should I choose to.

An externally accessible storage area in the rear and a table that will attatch to the side.



The cargo area door may end up being a standard RV cargo door instead of a built one like it's drawn now. Can usually pick those up on Ebay fairly cheap.

The table could also be made to hold a permanent cook top and/or a sink.

On the inside you sleep facing the front of the trailer. Two decent sized interior storage areas above the cargo area with no worries about hitting your head when you sit up.



I like the idea of the door at the foot of the bed. I personally think it makes getting in and out easier.

Windows on both sides. Probably a vent or two in there someplace.

Sleeping space is 5' wide. 6-1/2' long. 4' high tapering down to 1-1/2' at the feet.

Storage areas are 2-1/2' deep, varying height.

So, now the questions.

First, general thoughts on the design are always welcome.

Second, if done as luan skinned foam for the walls and roof, should there be any problem keeping the weight of this down to under 1000 pounds?

[GPW]

TJ, just a thought .... with the door opening onto the bed , any dirt, leaves , bugs ,frogs, lizards, etc. that gets dragged in will end up in the bed with you ....Conventional TD’ers know this well ! Instead of a mattress , you could use some sleeping bags/ pads , and then you could sweep out the entrance before you roll out the bedding .... more floor space too ...

Yeah , no hatch , No leaks !!!

[TJinPgh]

Your point is well taken about dirt/etc. being carried into the bed through the door. I've had similar issues through out my years tent camping where, although I use an air mattress, the bedding still ends up getting filthy from laying on the tent floor.

Roll up bedding is certainly an option to deal with that. I had thought to do it possibly fold up, kind of like those simple fold out sleep sofas. Would elevate the "seat" area to 8" in stead of 4" when not sleeping. Would also provide some open floor space at the end when folded up. Might be too high to sit on at that point, though. Would have to do some body measurements.

Doesn't help much in the middle of the night, though, when you make those bathroom runs.

As you say, it's something all TD owners have to deal with. Which explains why so many have carpets and such in front of the doors.

Only so much you can do, I guess.

I figure to use a side tent of some sort. Maybe try to come up with some type of floor for it so those things get left out there rather than being drug into the camper.

[GPW]

Yes , those midnight bathroom runs .... I remember when Grandpa had a bedpan under the bed to save fumbling around in the dark (maybe a revival there) ... in military aircraft we had a “relief tube” ... but even a porta potty requires some bodily contortions to get to in a small trailer ... Just one of the small concessions we pay to camp out ... I remember in a tent , we had to go outside ... even in the rain ... The inside alternatives seem to be much better , especially if you’re a Pistol Club member...

TJ, considering your height, you could make the trailer that wide , and sleep sideways in one end , and give yourself an enormous amount of floor space... especially between the door and the bed... I didn’t mention when it rains in on the bed huh ...

[Wobbly Wheels]

Just a thought here, but some full extension drawer slides coming out of that hatch would let you mount a stove and cooler permanently and have a slide-away galley. One could also incorporate a sink that drains into a bucket. I see the value of a side-opening drawer here instead as others have done: anything to increase your galley space by using the structure of the trailer itself.

And yeah, a mat out front would be the K.I.S.S. solution to tracking dirt inside.
Don't most tears have the mattress going right to the doors ?

[TJinPgh]

TJ, considering your height, you could make the trailer that wide , and sleep sideways in one end , and give yourself an enormous amount of floor space... especially between the door and the bed... I didn’t mention when it rains in on the bed huh ...

Well, I admit that I am a little vertically challenged but I'm not quite THAT short that I can sleep sideways in a 5 wide trailer. I'd need to go 6 wide to do that. Which would either put me back where I was in overall design (on an elevated box) or have me building out completely over the wheels.

I'm really trying to avoid the latter. To be honest, I'm not overly fond of the hidden wheels look. So, I either go back to elevating it or max it out at about 5 wide for a more standard type of build.

Otherwise, I'd need to modify the trailer or replace it with something wider. Neither of which I'm overly keen on.

Hopefully, the side tent will resolve any weather issues I might find as well?

Just a thought here, but some full extension drawer slides coming out of that hatch would let you mount a stove and cooler permanently and have a slide-away galley. One could also incorporate a sink that drains into a bucket. I see the value of a side-opening drawer here instead as others have done: anything to increase your galley space by using the structure of the trailer itself.

Could certainly be done. The only potential downside I see to it that if it slid out the back then there would need to be another tent covering it. No hatch means no cover in the rain, either. Which is why I went with the side mounted table setup.

You could certainly do a slide out drawer on the side, as you mentioned. I suspect that it might be a bit above my pay grade for a first time build, though. Not sure. Would need to look into it more. Look at other builds that have done it and see.

And yeah, a mat out front would be the K.I.S.S. solution to tracking dirt inside.
Don't most tears have the mattress going right to the doors ?

Certainly the traditional designs seem to.

[TJinPgh]

Ok. So, here is the question that's been ringing around in my head. And, I'll use this design as the basis for it, but, I suspect it will apply to whatever I end up building.

Goes back to the question I (and others) posted about strength comparisons of foam compared to wood.

I stripped off everything from the profile of the above unit and came up with this as what I could consider the bare minimum hard points I'd want to consider for it.



So, now, the question.

If I skinned this both inside and out with 1/8" ply (and possibly something over the ply on the outside but we'll leave it at this for now), would 1x2 wood and 3/4" foam be thick enough to keep this wall rigid?

If not, how much thicker would I need to go or, conversely, how much many more 1x2 would I need to add to make the 3/4" thick wall thick enough?

[KCStudly]

I was quite surprised to find TPCE's torsion box floor (at 1-1/2 thick foam with 5 mm ply top and bottom, 2x2 side stringers, and a combination of 2x2 and 1x2 on edge xmbrs) to still have some flex. It is 64 inches wide x 9 ft - 8 inch long. If I pick up just one corner from flat I can get it up over an inch or so before the same side corner at the opposite end of the long side lifts (twist). A minor data point. It seems stiff enough over its length when lifting evenly.

From all of the talk of the incredible power of these torsion boxes, and pictures of people standing on their floors between saw horses and such, I would have thought it would have been much stiffer. People told me that 1-1/2 inches of insulation was overkill.

However, I do not have any concern whatsoever that it will be fully adequate. Some things that I did that may have contributed to a difference are that I did not glue the foam into the frame, I just fit the foam and face glued the ply skins top and bottom. Also, my plywood is made up of multiple panels instead of a monolithic piece. Still, once the box is built I am sure that it will be incredibly strong.

My walls are also 1-1/2 thk foam with 5 mm planned for the inside and canvas/paint planned for the outside. Can't really comment on these yet because they are not complete, but people tell me it is overkill. Maybe not for a foamie style.

Your design has the advantage of no galley hatch, which means that you have more of a complete box and less concern over the stiffness and stability of the more traditional unsupported galley "wing" walls.

I guess I don't have an answer to your question, just some observations that I have made during my build.

[TJinPgh]

Thanks for the input.

However I do this I will be gluing the foam in place and the 1/8" ply will be glued and screwed on both sides. Also looking at only 48" tall instead of 64" wide.

Also, I would think that a vertical wall would flex differently than a horizontal floor? No engineer here so I could be wrong on that but it seems to me that the stress would be pushing down on it differently.

Should make for a fairly solid piece. Just not sure what the minimum thickness is I can go with studs in those locations and still have it be solid enough.

Back in the day, a single piece of 3/4" ply was considered more than adequate for the wall of a TD.

Total thickness with 3/4" foam would be 1". Not sure if that's enough to compensate or not.

[KCStudly]

Yeah, I just mention my experience with my floor because it is similar construction to your proposed wall and, for me, it is complete, so that is what I have experience with.

The orientation is not so important as the way that it will be loaded.

If I were to use my floor for a wall, and supported it at the front, along the top and bottom, at hatch hinge with the bulkhead, spars, 1x2 cabinet face frame (i.e. ladder frame) and counter top, then if I pushed in or out on the corner as if a galley wing wall, I expect that it would be exceptionally rigid, which, essentially is what I have planned for my walls.

The beauty of these little things is that seldom does anyone say, "man I really screwed up and it was a complete and utter failure ending in disaster". More often it is, "I love my camper and we had a great time, learned a little something and if I every make another I might...".

So whether you decide on 3/4 fill or more, I am sure that you will be successful. Just remember to tie everything together. The strength is in the sum of the parts.

Build on.

[linuxmanxxx]

I have built 4 builds now and all were 3/4" in the walls and floor and 1 1/2" in the roof and all skinned differently trying various things. I can tell you that with 3/4" foam 1x2s and 1/8" panelling inside and 5mm luan on outside produced a structure I could stand on the roof. You have to remember as you close it all in and connect the pieces the whole structure keeps gaining massive strength from spreading all the load points around.

Take a 3/4" sheet of plywood at the store and pick it up and note how much it bends vs what you were saying the torsion box was flexing. Torsion is lighter stiffer and stronger than plywood any day so don't doubt doing a hybrid sandwich build as long as you use the right adhesives to bond everything.

If you build more than one of these doing the torsion box it gets massively easier after the first build and I'm sad to see a lot of people on here say they'd just go plywood on their next build because the sandwich was too complex, expensive, and time consuming. Time is worth spending when you start seeing the massive weight differences between the two plus the strength gained with the weight shedding.

You don't believe me on the weight go to the store stack 2 5mm luan and a 3/4" sheet of foam and lift them and then go lift a single sheet of 3/4" plywood and bet that will get you thinking more toward stick framing, sandwich building, and torsion box wheeling and dealing campers

[rbourne3]

Ok. So, here is the question that's been ringing around in my head. And, I'll use this design as the basis for it, but, I suspect it will apply to whatever I end up building.

Goes back to the question I (and others) posted about strength comparisons of foam compared to wood.

I stripped off everything from the profile of the above unit and came up with this as what I could consider the bare minimum hard points I'd want to consider for it.



So, now, the question.

If I skinned this both inside and out with 1/8" ply (and possibly something over the ply on the outside but we'll leave it at this for now), would 1x2 wood and 3/4" foam be thick enough to keep this wall rigid?

If not, how much thicker would I need to go or, conversely, how much many more 1x2 would I need to add to make the 3/4" thick wall thick enough?

I built mine thinner. I wanted to use Grant's hinges, so the walls had to be exactly 1" thick. I ripped the framing 5/8 wide from better quality 2x4s and covered both sides with 5.2 birch. I used 1/2" foam. Each wall weighed 45#. I used no screws, only glue and clamps. I did use staples in the roof. My 9'6" x 4 weekender weighs just over 500 lbs empty. Since it is so light, I can lift the wheel by pushing the top of the side. Build - http://thebournes.us/weekender/index.html

[TJinPgh]

Steve,
Thanks for the info. You said you used 1.5" thick on the roof. Do you think that's the thinnest you could have gone with that?

rbourne,
Thanks for posting that. I see a lot of similarities with what you did and the overall thinking behind what I want to do.

I'm still trying to figure out where you used the 1/2" ply vs. the 5mm stuff. But, otherwise, I see no reason why I can't do this in a similar manner.

Do you have any close up pics of how you ended up connecting the walls to the floor?

[linuxmanxxx]

I did one of the rods in 3/4 and it sagged and none have sagged doing 1 1/2.

[TJinPgh]

Good to know.

Thanks.