mERVn the Ski & Climb E450 ERV

whitenab

New member
About us:
We love climbing, skiing and being in the mountains. We want to have a place to stay other than the back of a pickup and eventually take some extended time off of work to ski & climb before our knees hurt and fingers ache. I’m an engineer & my girlfriend works at one of the big apparel companies in PDX.

The Goal:
Have snowy roads & light off road ability coupled with the amenities to stretch from a weekend trip to full time skiing & climbing without completely breaking the bank.

The Considerations:
Truck & Camper: Maybe the easiest option. However, buying a nice truck + a leak free Northernlite/Bigfoot camper that we were going to gut and remodel would not have been substantially cheaper from what we would have bought + a walk through for us was worth a fair bit of money.
Sprinter Van: Not 4wd without huge price tag, questionable dealer service network, narrow. Driving quality is nice, and we have driven my parents quite a bit & liked it.
AWD Transit: Living space is tall but skinny. AWD w/ options was still quite $$$ but would be our choice if buying a new van. Driving is pretty nice & we like the ford dealer network options better than Mercedes.
Shuttle Bus: More flimsy in our opinion, good footprint, generally no built in front passenger seats. Less than ideal access to storage from outside. 4x4 conversion possible, v10, 7.3 ,6.0, 5.4 pretty much all the ford engine options which is cool.
Box Truck: Usually work trucks, hard to find with the right mixture of rear doors, roof, pass through & on a ford chassis. I like them (GF doesn’t) but for the size we were looking at most of them sit above the wheels & have a really high center of gravity it appears.
Various 4x4 RV Rigs: Almost all of them are $$$ and most of them are converted already and we wanted to do that ourselves to our taste.
Ambulance: Nice box quality, but usually ran hard, too much exterior storage & we both dislike the ambulance style built ins. Quite a few 4x4 options though for pretty good prices.
ERV's: Ambulance box build quality, very little external storage (good), not ran that hard. Built on Ford e450 chassis, all the older ones I’ve seen are on the 7.3. Unfortunately DRW and rwd, but nothing too crazy to convert to 4x4. Cab amenities are simple and sparse but seemingly robust.

After lurking, looking, thinking, and planning for almost 2 years my gf and I finally pulled the trigger on a base vehicle.

The Choice:
2001 E450 7.3l v8 Turbodiesel ~110k Miles
Previously a Redcross ERV
DRW
Wheeled Coach Box

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We drove it home ~600 miles last weekend. A little bit of shake sometimes when braking we are going to get checked out - otherwise the thing drives great!

To Do:
There’s a long list of small & large things. Here’s a sample: get everything out, put insulation & flooring in. 4x4 Conversion. Fill old holes in the bottom of the box. Add a side door & vent. Map out the electrical & move electrical box a bit. Replace rear door hinges. Decide on fuel source for the box. Then uh, you know, finish the rest...easy.

But actually our goal is to have an insulated an heated rig with a bed by January or so so we can stay in it up at Meadows during the weekends this winter.

Progress:
A couple of weeknight evenings of work and we've got it mostly gutted. It's actually amazing how solid everything was. Very impressed with the build quality of these things. Mom & dad came up to lend us some tools and a hand with some of the big parts we had to remove.

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General Musings:
Was hoping the side door would have a more open space in the side to fit into. Too many ribs and cross members on the box. We are going to have to do some serious cutting & frame building with aluminum & probably will end up paying someone to do it.

At first I was worried about the built in electrical system but I think I'm in favor of it now - it's well laid out, labeled and has great wire organization. I am not an EE, but I think we'll be able to figure out switching in LED's for over heads, adding a fridge & heater line, into the existing infrastructure. It's definitely less complicated than a standard ambulance which is a plus in my book.

Thankfully, the neighbors on either side of us actually seem pretty stoked on it. Also hopefully some of the loudest parts are over (sawing off some bolts & screws) so we can work later in the evening because Work->Truck Work->Work Out is hard.

Questions we are thinking about.
We are thinking about leaving the diamond plate and building on top of it. Should we reconsider that?
Anyone know someone in PDX that we could do the side door aluminum work through?
Does anyone want any slightly damaged ambo style built ins?
Paint options? We want to paint it. Tempted to raptor liner it, but we're also not a huge fan of having texture on everything.
 

whitenab

New member
A little bit more progress. Lights, ceiling panels & old insulation all out. Just a couple panels left & the box around the electrical & ac/heat.

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Weekend Goals: Finish the gut. Clean inside & out. Assess what is under the diamond plate floor and consider possible removal.
Stretch Goal: Put the floor in.

(Literal) Floor plan:
1570810726578.png

Current plan is to just fix the floor to the diamond plate since it's plenty strong & it's connected to the aluminum frame underneath.

1570810792046.png

We are considering adding a sound barrier such as Quiet Walk on top of the plywood. Our current plan is to go with 1" insulation, and looking at 1/4" or 1/2" plywood sub floor then laminate flooring. So we are looking at ~1.5inch loss of overall height.

Wall Insulation Thoughts:
mERVn is flat & right angled so it's setup for easy XPS insulation everywhere. It's cheaper, less stuff in the air from it during insulation and use and has a slightly higher R-Value than what we were considering originally for batt insulation. That said, are there significant insulating advantages to having a batt style insulation fill those spaces just a bit more than the XPS we would cut? A lot of people do spray foam insulation but we are going to pass on that. No interest in doing it ourselves & we dislike having things fixed in the walls that you can't remove.

A nice plus for XPS is that it has a fairly steep increase in R-value as temperature drops compared to others as seen in this graph which is good for the winters & cold fall & spring days.

1570812793855.png

The wall cavities are 2 inches deep and to prevent thermal bridging sucking all of our heat out we will be going with atleast 1/2 an inch, but maybe a full inch of XPS over the the outermost aluminum on the walls & ceiling. I'm not sure how much we should use to stop thermal bridging and how severe of a problem it is. More research is needed.
 

whitenab

New member
10 Days of Progress:
Floor is in.
Wheel Wells Boxed
Most of box is insulated.
Some wall paneling up.
Electronics are slowly being sorted

Walls:
2inch insulation in each cavity:
1571697932351.png

Covered in an additional 1 inch XPS in order to mitigate the large amount of thermal bridging that would occur with the large aluminum plates exposed. This also helped fill the space between the wall and the inside of the diamond plate trim that the 2x4 furring strips are notched around.

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Any places where it was really time consuming or inconvenient to put XPS we re-used the batt insulation from the tear down.

Walls in and driving.

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Challenges Ahead:
Door & fan installation. Both will require cutting supports and since the outer shell is attached via adhesive not riveted or something else we will need a frame to hold the skin to. Soon our progress will hinge on those things.
Window framing.
Installing our electrical system that will run side by side the boxes stock electrical.
Bed-frame/cabinets etc
 

DzlToy

Explorer
You guys were moving at a good clip. I was going to suggest removing the diamond plate floor, as it is a large heat sink and probably quite heavy, but I see that is no longer an option.

It is difficult to calculate heat lost through a "wall system" such as this, but you can estimate it if you want to do some calculations. This will help you design your HVAC system and figure out heat up/cool down times. A solid XPS wall, sheathed in fiberglass, for example, is much easier to account for.

The R-value graphic is quite interesting, especially with Polyisocyanurate coming in below XPS. Some data I have seen says the exact opposite.

Have you chosen a path for the 4WD system?
 

whitenab

New member
I've been slacking on the updates - framed the windows in last night & almost finished getting insulation in. The big hurdle of door selection & cutting is still in front of us. Considering a shorter door ~58" if we can find it. A change in what was designed above is that we decided not to go with the framed in floor and instead it is semi-floating on the diamond plate with the gaps around it filled with expanding foam. Agreed about wanting to remove the diamond plate however, we left it in and we are going to live with it.

What data have you seen about polyiso? I've not seen anything contrary. Another disadvantage at least for the floor is that the commonly available polyiso boards have lower compression strength so you would need better framing & rely less on the strength of the XPS.

Currently trying to figure out best practice for the roof so that we get the most R-value without losing major height. Looking at different options to stop thermal bridging via the cross bars. Considering some 2" wide foam tape that will add a bit of something between the metal and the air.

4wd - we are planning on going with a guy out of Bend "Vanmafia 4x4". I'm not quite versed in all the details but it will be very similar to this truck here: https://expeditionportal.com/forum/threads/2002-ford-mobile-concept-4x4-adventure-van-sold.207966/
 

DzlToy

Explorer
Sorry, I should have clarified that the graphic you included shows that Polyiso is out-performed by XPS at some temperatures, but not all. Maybe it's not too late for you to take advantage of this.

According to the National Roofing Contractor's Association Long-Term Thermal Resistance Report, Polyiso has an R-value of 7.2 immediately after manufacturing, settling to R-6.6 within 180 days. The graphic seems to indicate something around 5.2 at 75F. A value of R-6.6 would place it above Dow's Thermax.

PIMA 101 calls for preconditioning foam samples at 75 F for 180 days before testing. Using RIC/TIMA 281-1 or PIMA 101 pre-conditioning, R-values of about 6.6 per inch thickness were reported.

I don't want to muck up your thread so let me know if you don't want this in here and I will take it out.

Edit: heat is transferred in three ways; convection, conduction and radiation. In order to have a well "insulated" space, you should address all three of them.

Convection is air movement, i.e. forced air furnace in a home. (molecule to molecule transfer of heat inside a wall or space)

Conduction is the handle of a cast iron skillet getting hot even though it is not touching the flame.

Radiation is a heat source, i.e. sunlight, warming a surface, i.e. metal ambulance box, with infrared light. Reflective materials can reduce this, but are not actually "insulation". They are just reflecting heat like one of those car windshield things on your dash.
 

whitenab

New member
No you're all good this is worth talking about! I think a key design parameter for each rig is understanding the desired climate to be comfortable in. For us the goal is to find temperatures between 72F and -20F depending on the season.

There's no doubt that Polyiso has the higher-value at higher temps but insulation at 75F is just not something I think is actually a valuable number to judge at. If my primary concern is cold temperatures <32F then, XPS and Polyiso shake out either the same or XPS is better based on the behavior shown in the above graph, especially near 0F. That's assuming that the trend shown in the above graph holds true.

And yes, those three transfer methods need to be dealt with together. For our usage case it makes little sense to deal with radiation with anything more than finding a shady place to park. I would argue that for most people this is sufficient as well. Convection is dealt with by our rigid foam insulation that fills the walls with 2inch xps & covers that surface + exposed metal from the box in an additional 1inch (which helps stop thermal bridging from the aluminum studs etc) . Partnered with A propex heater I believe we sit okay on the convection front. This leaves the ceiling that has 2in of XPS between ribs coming to ~R10-12 for our desired usage temps and the dilemma of how to deal with the thermal bridging of the roof supports without compromising much headroom.
 

DzlToy

Explorer
Fair point. Most people do not go camping in 0F or even 32F, so you are wise to build for those conditions if you are going to be cold weather camping.

Heat loss, or gain, through a wall system, is not difficult to calculate if you are willing to do some math. Since we do not have exact figures, I am going to make some presumptions. Feel free to correct me if any are way off base or out by orders of magnitude.

Box dimensions of roughly 12 feet by 6 feet by 7 feet. Inside this box is about 500 cubic feet of air. One BTU is the amount of energy required to raise the temperature of 55 cubic feet of air, by 1*F. This is in a perfect world, not a snow storm. So, to get a baseline, you need approximately 10 BTU to raise 500 FT3, by 1*F, or 700 BTU to raise the temperature of that air from 0F to 70F. We both know a 700 BTU (~2400W) furnace will not accomplish this.

So, we need to approximate heat loss through the walls. If you estimate the surface area of the box using the dimensions above, you have approximately 400 square feet of "box". This does not account for windows, weather stripping, cab pass through, etc. I cannot do FEA on my phone. :D.

A 1.5" thick XPS sheet loses 0.123 BTU per hour per square foot per degree Fahrenheit temperature delta. With 400 square feet of "box" and a 70F temperature difference (0F outside to 70F inside), you will need at least a 3500 BTU (12kW) heater just to keep up. This does not include air coming in through seals, hatches, doors or windows. Plastic RV windows can have R-values in the 1-2 range and the same is true for roof hatches and sky lights.

Warm clothes are cheaper than diesel/propane, humans put off about 100W per hour and you will get some heat from cooking and appliances.

Hope that helps.
 
Hi whitenab, you guys are making great progress! We have a similar unit but E-350 and SRW. We removed the large serving window, narrowed the opening using aluminum sheet, doublers, marine sealant/adhesive, and blind rivets, and cut the door-width opening down to the floor. Installed a new RV door we got cheap at an RV surplus store. We are loving it so far, and my wife and I were able to complete the job start to finish in about 7 hours with a less-than-stellar tool selection. Let me know if you want any pics - don't want to muddy up your build thread.
 
Also, regarding the fan installation, we found the 2" square tube roof beams to be 14" on center, leaving 12" between the beams. With our Maxxfan requiring a 14"x14" cutout, we just cut 1" locally from each of the adjacent 2" square tubes. Since we didn't entirely bisect any roof beams, and found the resulting structure to still be quite sturdy, we did not do any reinforcing or framing around the fan cutout.
 

19Spec3

Member
I just bought an ERV -- 2002 E450 with 108k miles (Unit 2140). I'd LOVE to see some photos of your side-door install.
 
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whitenab

New member
Wow I am apparently awful at updating on here, really thought I would be better. Great to see some others with ERVs out there! We have not yet put in the side door but are making that the late summer/early fall job before winter comes back around.

MountainsAreCalling please post some photos it would be great to see no worries with muddying this "build thread" that I failed miserably at! :)

OCRent I'd love to see your rig as well!

I'll post some updates of where we are at/where we've gone in a bit.
 

whitenab

New member
8 Months In Brief
We started out in a sprint to get the truck ski season viable. We did not want to feel like we are in an ambulance or anything like that so we worked on the inside first and got it up to where we were going to be warm and comfortable.

A little over 7 Months ago right as we were getting tired of working on it and wanted to start skiing.
1594328818637.png

5 Months ago on our 2 week ski road-trip...The inside:
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The outside at Pebble Creek.
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Bonus Picture...One of the cool features of the ERV is the possibility for enormous under-bed storage. Full width doors and the box is ~7feet wide inside. Skis fit sideways even if you are a TGR dad or just someone who thinks they still need 200cm skis.
1594328595982.png

We've added some more stuff since then and changed some things but it's basically this.

Highlights:
- Starting it up. Our coldest night it started on it's second crank.
- Warmth...Low temp somewhere near -5F for a night or two in Montana. When we kept the heater cycling it was perfectly fine.
- Snow performance was much better than expected. Including 3-5in loose snow going up a hill. Definitely a bit of rear float but powered right through. We have winter tires. The only place I ever felt icy condition at all effect driving was in Ski Resort parking lots. We have not added 4x4.
- Bed height. It feels really good to sit and hangout on our bed and it still has so much storage underneath. If that wasn't your priority, raising the bed another foot or more and getting a thinner mattress, the storage would be absolutely insane.
- The rear step. It's really nice and we have a piece of fabric over part of it that makes it comfortable to stand on in your socks.
- Propane access from in the inside

Low-lights:
- It is quite loud in the cab. Need to do some more digging into how to reduce engine & road noise.
- Some fairly expensive maintenance work done on the engine and brakes. Pretty stoked on most of the truck. Pretty unhappy with the diesel mechanic that we paid to look it over before we bought it.
- Ran it out of gas one day - found out the gas gauge is off by a bit more than an 1/8th of a tank. (maybe this is a highlight? It puttered out as we rolled into the gas diesel pump)
- A door handle and storage box handles broke. Fixed the rear door latch but not the storage box yet.
- Last weekend we turned around from skiing Diamond Peak because we felt the road was too narrow and rutted for us to feel comfortable. Had we had a 4x4 and/or a lift I think it might have been a different story.

I'll try to be better and add a bit more info on the things we've built/done that I think are worth opinions on like the propane locker, winter tires, our propex heater, lights, and anything else I can think of.
 
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eporter

Adventurer
Great build, I just looked up this thread wondering if there was an update.

Have you heard of quadvan here in Portland? They do tons of 4x4 conversions on brand new E series vans. As a result they have lots of brand new takeoff front ends for sale cheap. So for not much money you get brand new brakes bearings beams etc. Apparently there is a local Les Schwab shop that the owner has been sending rigs to for the conversion. The E series didn’t really change much in the front end from late 90s to present. So with the front end swapped over and some slightly bigger springs, and then new leafs, you can get a decent lift going and improve braking and handling performance.

I spent a bunch of money getting my old ambulance’s front and rebuilt. When I had a Chinook project, my plan was to swap things over with the quad van parts.

That’s great you got out on a ski trip. That was my dream goal with the Chinook.
 

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