Lifting roof XPStream - Almost Finished!

[OP827]

Once it is back in the shape you want, adding some stiffening ribs (foam ribs laminated in place), akin to the old station wagon roof ribs, either on the inside or outside, would help stiffen things up.

Also, have you considered post cure heat? Supposedly elevating the epoxy temperature to 160 - 190 degrees and soaking it for a while using lamps (or sunlight) can add quite a bit of strength and stability.

KC, yes post cure is definetely an option, the only thing to be aware of it outgassing that rigid foam or whatever minor trapped air inside the laminate can produce. I found one time hard way that the additional applied heat, after the layup was done, has created some delamination around the small penetration holes, I described it some time back in the build thread. I think post layup elevating the temperature would work reliably with vacuum applied, which is not an option in this case. I will though maintain 70+ F degrees when I do this roof fix to ensure complete cure. It will take some time. Having said that where I will be using the jig to press things together, elevation of temperatures will be actually a good idea, thanks!

[OP827]

If you have to live in Alberta.....you might want to consider more "Pitch"
Look at he houses in Revelstoke and up at the ski hills????
Sorry, just couldn't resist.
Brian

Ideas of high pitch roof and streamlining of travel trailer lines do not blend well.
Or A-frame foldable trailer then? But again during storage the flat roof panels are prone to sagging anyways. All tent trailers or other trailer roofs are prone to sagging in a long run.

[Bluebunny]

Hi OP,
If you have enough arch in the roof, its flattening will tend to splay the attached walls and outside edges outward as the dome flattens. Inexpensive garages are built with horizontal "headers" with no roof trusses...

The thought here is if you have enough arch, horizontal tension and/or stiffening of the roof edge might help hold it in shape. In any event, the lesson here is when in storage during snow season, a forest of roof props would be prudent...

[KCStudly]

If it is just cosmetic, maybe just adding a crown to the outside would be a lot less work than what you propose.

I have a similar dilemma on my curb side wall, a shallow but wide dip.

[OP827]

If it is just cosmetic, maybe just adding a crown to the outside would be a lot less work than what you propose.

I have a similar dilemma on my curb side wall, a shallow but wide dip.

KC, could you explain how to add a crown to the outside, what do you mean?

[OP827]

Hi OP,
If you have enough arch in the roof, its flattening will tend to splay the attached walls and outside edges outward as the dome flattens. Inexpensive garages are built with horizontal "headers" with no roof trusses...

The thought here is if you have enough arch, horizontal tension and/or stiffening of the roof edge might help hold it in shape. In any event, the lesson here is when in storage during snow season, a forest of roof props would be prudent...

Hi Bluebunny,
The arch will not be enough to generate any measurable splay, we are talking about one inch on a 2 meter long arch. Horizontal tension with stiffeners pre-stressed and glued below with a clamping caul jig as described above is what I'm considering doing unless some simpler option comes up.

[KCStudly]

If it is just cosmetic, maybe just adding a crown to the outside would be a lot less work than what you propose.

I have a similar dilemma on my curb side wall, a shallow but wide dip.

KC, could you explain how to add a crown to the outside, what do you mean?

Laminate 1 or 1/2 inch thick sheet of foam onto the roof; use a long board to sand a crown into the shape, fairing the edges of the new foam out to near nothing at the edges; fair the edges with thickened epoxy as required; and laminate another ply of glass over all to cap it. The reason I recommend this is that it does not risk losing the fit to the cabin that you have already established; and it adds depth and strength to the roof section w/o weakening it first. It seems easier to me than making and handling all of the tooling you propose, and I suspect you will have a harder time matching and fairing a cut, and all of the ribs than you would blending a cap to the outside edge.

Sure it would take more foam and glass, but you seem to be pretty well invested in those supplies anyway, so...

[OP827]

Thanks guys for your constructive input. Based on all particular conditions with the roof, I have decided for lamination of stiffening ribs on the roof internal surface. I do need to reduce the curve of the roof a bit so these siffeners will be beneficial for that. Making jigs and cutting the wood was easy.
Here is the front roof section being added with two stiffeners.




Merry Christmas and Happy New Year to all.
May the Peace and Prosperity be with you, your family and friends.

[Bluebunny]

Now you have ME thinking...Early in my design, I curved the flat ply panel in a long sweeping curve, which would prevent transverse sagging. To make my build easier, it's now two straight runs between a sweeping curve. So back to the drawing board to place 3/4" h external stiffeners to go between the outer foam. Great build OP!

[OP827]

...
To make my build easier, it's now two straight runs between a sweeping curve. So back to the drawing board to place 3/4" h external stiffeners to go between the outer foam. Great build OP!

Thanks for compliments Bluebunny, could you share some simple sketch to elaborate on how two straight runs between a sweeping curve would look like?
BTW I am only adding a small curve across the roof span w/o changing overall longitudinal roof curve, it will be just slightly smaller than the current one on the panel and it should look better overall, imho

Also Some clarification on my photos above. The stiffeners are those small wood inserts under the foam covered in packing tape for separation; the groove in foam is to serve as fiberglass mold since the wood strip is covered with several layers of glass cloth for stiffness and strength. I will keep the cauls on for 4 days to make sure the epoxy is fully cured, this is to eliminate creeping.

[Bluebunny]

...could you share some simple sketch to elaborate on how two straight runs between a sweeping curve would look like?

Hi OP,

Shown is the clam down, shell only, guts removed. The original roof had a much longer curve, with flat spots only near where a bulkhead was underneath. I predicted that difficult to build; large panels, and how to get to the joints? From your good advice. added flat runs to allow building upside-down on the garage floor. In any event, thin flat stock can warp, oil-can, and generally misbehave if allowed to. If the flat stock is say bent into an arch longitudinally, it will strongly resist bending span-wise. Like corrugated roofing is stiffened by its many bends.

After your snow incident, I think I'll add roof stiffeners as you are doing. You can see the little buggers along the flat runs. Decided to add to both inside and outside, and plan on using temporary internal poles to help support the roof if stored out in winter. A 5 foot wide by 14 foot long roof can build a lot of weight!

Enjoy the holidays; hope you extra time to work your project! Looks like it will be nice and roomy!

[OP827]

Hi Bluebunny,
this sketch concept looks very good, if i were you i would probably run some calcs so that there are enoug stiffeners to take snow load as well, as a piece of mind, or you think it will become to heavy? with only 5 feet span not six, the spars do not need to be big and they can be made more rigid with fiberglass tape epoxied on the lower edge. since i am adding the stiffeners every twelve inches the roof now should take moderate snow load with no issues, just in case. although the trailer is designed to stay in carport or garage.
i really like your ctrailer concept.

[Atomic77]

Merry Christmas Oleg!

[OP827]

Merry Christmas and Happy New Year to you too, Michael!

[dales133]

Merry Christmas oleg