What if: Jack Frost not welcome here!

One of my complaints about the van is how quickly the interior heats up on hot days and cools down on cold,days, though, because of radiant energy, the heating is more drastic than the cooling.

True, having a structure that isn’t essentially a steel box is a good start towards resolving this, but a little insulation never hurt anything either.

Planning for 2” thick walls, and allowing for a ¼” skin on either side of the wall, leaves 1.5” for structure and insulation.  

I could carry that even further and plan for thicker walls with more insulation, but since the windows, poorly insulated single pane RV style, will comprise about 35% of the exposed sidewall area, and the structure, also a relatively poor insulator, another 8% to 12% there is a point of diminishing returns on adding insulation.

I can compensate somewhat for the windows by having insulated inserts/curtains on hand to put over them on those cold, cold nights or as protection against the raging sun, (I use Reflectix metallic bubble material in the van and, judging by how hot the sunny side gets, it has proven to work very well.) but there's not much I can do about the thermal-bridging created by the structure except use wood rather than a metal of some sort because the former, though a relatively poor insulator is one heck of a lot better than steel or aluminum. Which works out really well for me since I'm definitely a wood man. No, not that kind! I'm talking about wood that grows on trees!!!

In addition I'm looking at using a roll-on bed liner paint, which now comes in a whole variety of colors, over the entire shell as the exterior finish. I've been a long-time follower of Glen Morrissette's blog and about a year ago he built out a Volkswagen van to be his full-time home and used this type of paint on the exterior of the whole van.

Since he has barely mentioned the finish in the year since I would guess it's holding up pretty well. (And he isn't shy about abusing it by driving down very narrow wooded tracks either!) I don't know if this finish has any desirable thermal conductance properties but it can't be any worst than the usual Filon (That fiberglass sheeting you see on the exterior of some RV's today.) and certainly better than the aluminum skin you see on most the other RV's. I'll also bet it's a lot easier to renew or repair dings and scratches than the other skin options as well.

For an extra bonus, a painted surface creates a mono-coat skin, unlike the other two exterior options mentioned, which have seams at the corners that require calk and trim. To carry that attribute even farther, by rounding over the corners slightly, say with a 3/8" round-over bit, and finishing them off with a lightweight fiberglass tape laid in resin, I can eliminate troublesome sharp corners (Paint likes to migrate away from sharp edges as it cures) and add some extra sealing and strength to the vulnerable joints.

But that's more about construction and this is supposed to be about insulation. So, either high density foam blocking or sprayed in foam insulation will be my choices.

I’m a fan of high density, closed cell spray foam for a few reasons. It has a very good R factor per inch, is very good at sealing up air leaks and also acts as a vapor barrier. And, when you build the wall structure and apply one of the skins then fill the voids with spray foam, the foam bonds very tightly to everything it touches, seals any possible air leaks, and when cured adds greatly to the structural integrity of the component.

Being closed cell, even if water leaks in past the outer skin somewhere, it has a very hard time penetrating the closed cell foam so is less likely to saturate hidden areas then lurk and grow nasties.

But then, no matter how skilled you are at spraying the foam in, you have to cut and shave it flush with the open side of the structure before you can apply the second skin. And spray foam is expensive stuff, costing about $1 per board ft.  A 10’ square area 1.5” thick would require about 15 bd. ft. of foam or $15 plus over-spray and waste.

This is a photo of the open cell foam sprayed in to insulate the steel barn some 9 or 10 years ago. You can see the rough surface left behind even by professional installers. (The closed cell foam I sprayed in myself to insulate the well-house is completely concealed so I can't get a photo of it but looks about the same except it's blue.)

Block foam is less expensive than spray, coming in at about $6.80 for the same 10 square feet. But that doesn’t account for the waste of cutting 4’x8’ sheets to fit the bays in your walls. And you want the fit to be tight so air movement is minimized, so careful cutting and fitting is required. And to get something similar to the added structural properties of spray foam, you want to glue the block foam in place with an evenly spread coat of a good adhesive, all of which adds to the cost and labor. But then again block foam can be bought in 1.5” thick sheets so once it’s installed the exposed surface of your bays are already nice and even when it comes time to secure the second skin.

One of my previous, block-foam insulated, rigs under construction.

Having learned from experience that getting block foam properly fit and fastened requires a great deal of care and patience, and even then will still require a little extra sealing around the edges, I’m leaning towards the spray foam, which I've also used in the past but not in a rig before.

Trouble and Triumph: The windshield saga

I think people are far too eager to blow things up into sagas when they are simply events. I'm not a fan of the misuse of language ('I don't believe in - ' is one of my hot buttons. What do you mean you don't believe in violence?? You actually don't think violence exists!!!) but in this case event started piling up on event, so I feel justified in calling what follows a full blown saga.

Faithful readers (All 2 of them!) may remember that back in July the van suffered a grave indignity up in North Dakota when her windshield was cracked by a flying rock as I drove south out of the Roosevelt National Forest.

Once I got over the shock of this grievous injury I decided to try and hold off until February to replace it since two of the three windshield stickers have to be replaced then anyway and the third would be expired, but the small crack, as small cracks are wont to do since they apparently have crack-envy, kept getting larger. While driving I would keep a close eye on it because this seemed to stop that growing crap, but inevitably my eye would wander and next time I looked the crack would have run just a little farther.

One wasn't enough, so two more cracks were added to the menagerie

But this was a greedy crack so one just wasn't enough, and while the van was parked back at home base, two additional cracks were spawned in the dark of night. (Actually I suspect it was the light of day and caused by the Reflectix sun visor in the windshield. I've noticed that things get really hot on the sun-side of this material, which is good since that's all heat that didn't get inside the van, but maybe not so good on a failing windshield.) I could feel these cracks when running the edge of my thumbnail over them, indicating that the glass was shifting as the cracks released it. Cracks which now reached from the far right edge to a little more than halfway to the left edge in a snaking path. So, forced unwillingly into reality, I bit the bullet, and scheduled a replacement at one of the two insurance company sanctioned places in town.(It's a small town but I still don't know where the other place even is!)

By this photo, which admittedly doesn't show it very well but you try photographing clear glass!, the crack was running from the far edge of the windshield  to across and off the left edge of the photo!

Which is how we ended up going to town in two vehicles on Monday. I had a appointment for 0930 and should be able to pick the van back up shortly after lunch.


Trouble:

Monday:

I had a bad feeling when I dropped the van off and was told by the the woman behind the counter that the installer would get started as soon as he got back from the chiropractor's, but, choosing to ignore that bad feeling for the more pollyanna-ic stance of glass-half-full, I left her there anyway.

With my head in the sand we stuck to our original plan and went on our annual pilgrimage to Cabela's where I would buy new go-to-town boots. (My current go-to-town boots would be demoted to shop boots and my shop boots, the soles thin and badly blown out almost all the way around and the uppers well stained with various paints and glues and burn-marks, would be thrown in the trash.)

Cabela's is plenty far enough away, the better part of a tank of gas, to keep us busy during the windshield replacement and cure time.

Phone call 1, them to me sometime between town and Cabela's: Voice mail because I don't answer my phone unless I recognize the number and I never answer it when driving.

Phone call 2: Me to voicemail "This is so-&-so at the glass place, give me a call."  OK, that's not good!

Phone call 3: Me to them. No answer

Phone call 4: Me to them on a different number. Busy signal.

Wait 15

Phone call 5: Me to them: "Yes sir,  thanks for calling, I wanted to let you know your van won't be ready until later this afternoon because the installer is running late."

Phone call 6: Them to me. (I recognize the number now and answer.) "The installer's shoulder is just too sore for him to do your van today. He'll get it first thing in the morning and it should be ready by lunch tomorrow."

We do not pass go, we do not collect $200, we go straight home; van-less and resigned to a second town-trip in the same week.

Tuesday:

Phone call 7: Them to me. "That is a really big windshield so I'm getting a second installer in to help my guy so it will be late this afternoon before it's ready now."

Phone call 8: Them to me. "The second installer is here to help but when they moved your van around to work on it they realized that the Sprinter requires a special urethane which we don't have. I'll order it overnight and they will do your van first thing in the morning."

OK, this is a little inconvenient since we didn't pick up any fresh veggies yesterday, anticipating going in to town again today, and now we're getting pretty low. Not to mention I'm having separation anxiety and haven't slept too well. (This is the first time I've been more than a long hike away from the van since the day I picked her up, and never overnight!)

Wednesday:

Phone call 9: Me to them. "Just checking to make sure everything in on schedule before we leave the house for the long trek into town." "Let me check with the installers on when it will be ready and I'll call you back."

Phone call 10: Them to me. (It's been a lot longer than what I think a quick check with the installers should take and I'm not feeling the warm-fuzzy!) "Turns out our supplier didn't have that special urethane in stock yesterday and it won't be here until tomorrow now. I'll have the installers start on your van as soon as the shipment gets here and you should be able to pick it up around lunch tomorrow."

We resort to raiding the canned goods and do without fresh veggies for the day. I think I might be having withdrawals, but I don't know if it's broccoli or van!

Thursday:

Phone call 11: Me to them. "Just checking again to make sure everything is on schedule before we head for town." "They're putting the new windshield in now (I think I was so shocked I dropped my phone about this point.) and it will be ready after lunch."

We dropped off the recycling at the recycling center but had come to town much too early, so we went to a resale shop to bleed off some of the extra time, passing the glass place on the way and noting that the van was in the install bay (Well so far so good!).

After milking the used clothes and chipped dinnerware for all it was worth, we headed back across town, again passing the glass place, (It's a small town so you tend to pass everything.) and noting that the van was now sitting outside curing. (Holy crap!! This might actually work!)

We end up standing impatiently outside our favorite restaurant, still too early, but they took pity on us and let us in anyway.

After lunch we dawdled around the grocery store, checking and double checking our list, but enough was enough!

So I got dropped off up the street (The glass place has very little parking and we had the recycling trailer behind the car.) and hoofed the half block back to the glass place while the frozen raspberries headed for the house and the freezer.

I waited, and waited, and waited while the woman at the glass place tried to buff some scratches out of some other lady's smartphone screen (Yes, they replace glass, they tint glass, they sell audio systems; and they also sell cell phones and service, they sell health supplements, they sell - well, you don't really know what-all they sell unless you go in and wander around while waiting for them to finish up with someone that dropped their cellphone and now expects someone else to remove the scratches! Oh, and a TV over in the corner is permanently tuned to a God station just in case you have a personal crack or two that needs seeing to.)

It's finally my turn but the woman can't read the VIN number the installer wrote down so she can't finish the paperwork. The installer, who may be able to interpret his own handwriting, seems to have gone off somewhere for a nap. I go out to the van to get the insurance papers once again.

Triumph!!

I walk out with paperwork and keys in hand and make it all the way back to the house without the pristine new windshield popping out as I surf and twist and rattle the back roads to get there!

The world seems just a little more normal now with the van parked out in front of the shop. . .







 

What if: Doors and Windows

Doors:

 

I could get away with a 24” door but experience has taught me to go wider if at all possible, so I’ve offset the door, which of course is in the rear wall of the camper shell, slightly to the left to allow for a 30” door while still staying clear of the fridge and portable toilet over on the right side.

 The door is right handed, which means when you pull it open, usually with your left hand, it swings to the left, (I know; confusing but nobody consulted me when "they" were defining left and right hand doors.) placing the opening to the curb side, which is either the side of the camper where the rest of the campsite will usually be located or the slightly safer curb side if not in a campsite.

Windows:

Good ventilation and lots of light are a must, not an option, in a small space. Therefore I’ve designed for maximum windows while still retaining enough wall space to fit in some interior bits.

I’m a big fan of vent or awning windows as opposed to sliders because the former can be kept open in all sorts of weather that the sliders can’t handle. (I pretty much leave the awning windows on the van open all the time unless I'm actually going down the road.) This led me to the Hehr 4800 series vent windows.

The two opening windows opposite each other in the sides of the shell are about 14” high and 36” long and the bottom portion will open outward.

In keeping with RVIA (Recreational Vehicle Industry Association) design standards which stipulate that most RV's need a second means of egress, there is a 20” high, 24” wide escape window installed forward of the curb-side window, over what will be the head end of the bed.

I have the top edge of this window in line with the top edge of the awning window. If I decide to go with the clipped-corner shell this keeps the top of the escape window below the - well, the clipped corner. If I go with the straight sided shell as drawn here I could raise the escape window so its bottom edge is even with the bottom of the awning window. This gets the window up and a way from the pillow, (More coming on that, pillow location, soon, promise!) which might be a good thing, but then if I need to use the escape function the ground is a bit farther away. . .

 I used to be able to download  the RVIA Standards for Recreational Vehicles for free but now it appears to cost nearly $50. Good thing I held onto my old copy. I'm not a fan of government or other 'experts' sticking thier noses into my business, but I'm not at all shy about understanding and addopting or bettering various codes and standards for my projects. For instance, I  wired our barn and living quarters to meet or exceed NEC 2004, (The National Electrical Code in effect when we built the place.) even though there is no requirement for permitting or inspections in our neck of the woods.

Anyway, as I was about to say before that sidebar interrupted me; it’s not clear to me if the Hehr full escape window has a screen and can be tipped out like an awning window for ventilation, but the one in my father-in-law’s travel trailer does.  That would be good because that window is in the perfect spot for nighttime ventilation.

 Also in keeping with RVIA design standards, which stipulate that there be no opening windows in the rear wall of a motor home or slide-in camper, (To prevent exhaust fumes sneaking in.) the rear door will not have an opening window but rather an 18”x18” fixed window for light and viewing. (So you can make sure it's not a pissed off bear knocking at the door!)

Roof Vent:

And to round off the ventilation there will be a vent in the roof. This will be the Fantastic Vent with motorized open/close, rain sensor for auto closing, three speed fan with the option of in or out flow, and a thermostat control to automatically start and stop the fan.

The vent will be located in the center of the roof because this gives the best overall coverage and places the vent over open floor instead of something more delicate, such as the bed, in case the auto-close function fails when it starts raining.

Air conditioning:

Somewhat related to ventilation is the question of an air conditioner. I had entertained doing away with this particular annoyance by removing the unit on my van and replacing it with a second vent, but in the past two years my attempts at avoiding camping in weather requiring said air conditioner have not been very successful. So bowing to the inevitable, I am making provision for an air conditioner in this camper as well.

Rather than go with the traditional RV rooftop unit which puts an extra 100 lbs. plus wind resistance and additional height on top of the highest point of the camper where it does the most harm, not to mention getting in the way of solar, (But then I just mentioned it didn't I. . .I’m opting for a through-the-wall unit.

These are very similar to the ubiquitous window air conditioner but are designed to operate from inside the wall rather than outside, requiring something like only a half inch projection beyond the wall. While not common, I’m seeing more and more of these used in RV’s; the retro trailers by Riverside being an example.

While this does eat up interior storage space, it also lets me get the weight of the unit down off the roof and reduce the windage to pretty much nothing. If set up properly, and I felt up to wrestling with the 80 pound beast, I could remove the unit when I know I won’t need it, such as winter and/or boon-dock camping, and close off the exterior opening left behind with an insulated panel similar to an exterior compartment door.

More detail on how and where the air conditioner actually fits in the upcoming post on the bed area.

But first. . .

What if: After size it's all about shape!

So once I established the boundaries the camper shell has to fit into, I needed to figure out its shape.

There's not much leeway with the lower portion of the shell, but once I'm above the  bed rails I have a little more 'freedom of expression' to play with.

Granted, staying within the practical and affordable does severely limit the options here, but there are options. Though I’ve already eliminated a curved transition between wall and roof on this project. I’ve built a few of those and, good looking as they are, they are a bi----, a hassle, to construct properly without expensive jigs and forms and even then are time consuming.

This is the structure of the curved roof of one of my previous rigs. That white roll sitting on top is the Filon skin ready to be installed, but it took a jig, a template and a lot of work to get the structure to this point. By the way, it seems impossible, but under the grey tarp in the background is a pallet with all the pieces of the 50'x30' steel building that houses my shop and our living quarters out in the country where we now reside.

Tarp off, ready for the move to the country. Notice the cribbing under the pallet. That's pretty much a solid block of steel sitting there so this thing is heavy!!

So anyway, basically I'm left with building the shell with straight sides all the way to the roof, or easing the transition between shell sides and roof by clipping the corners.

Straight sides result in the simplest construction but the greatest surface area for cross-winds to work on.  Clipping the corners off at 45 degrees, though more complicated to build than straight sides, would reduce the shell's direct exposure to crosswinds by slightly over 25%.

At least that was my initial thinking,
but then I went back and factored in the entire crosswind exposure, including the truck itself, and added back half the height of the 45 degree panels to account for the vectored force a crosswind would have on them. Now the overall improvement in crosswind exposure dropped to less than 10%. So clearly the crosswind advantage of the clipped corners isn’t quite as extensive as I first thought it would be.

I also thought clipped corners would have the effect of reducing the perceived bulk of the camper, but after drawing up and comparing the two versions something different than expected became apparent. When viewed from certain angles the straight sided version actually gives the impression of being shorter, squatter, maybe even tougher looking, (And what guy doesn't want tougher looking!) than the clipped corner version, especially when viewed from behind.

From that angle the shorter sidewalls of the clipped corner version actually give the impression of greater overall height for the entire shell compared to the taller sidewalls of the straight sided version.

I didn’t expect that.

I think it has something to do with the narrower roof of the clipped corner version making the door appear taller in combination with the increased visual bulk of the straight sided version giving the impression of a squatter overall look.

From the inside there would be little visual difference since the majority of the clipped corners are hidden inside the cabinetry.

Straight sides would result in more cubic feet of storage space in the upper cabinets, but maybe not as much as it appears since the top back corners of cupboards tend to be the least utilized space anyway.

Straight sides would result in four fewer shell panels and four fewer seams to deal with during construction. Clipped corners would mean slightly smaller and lighter individual shell panels to handle during construction.

It might look like clipped corners would result in a slightly lighter shell but by the time you add back in the structure for those four extra seams I don’t think that will be significant.

So basically it comes down to complication verses overall look, and I haven’t come down on either side yet, so I will continue to draw it up both ways. Though I have to admit that I'm a huge fan of the late boat designer Phil Bolger who often designed for function and simplicity, ignoring looks altogether; which sometimes resulted in boats that are so ugly they're adorable, not to mention beautiful gems of functionality, like the Martha Jane or his iconic Super Brick.

To clip

                                   

                                              or not to clip

I don't know yet.

(And I have got to get that Hamlet speech out of my head!!)