cm
Dillon, CO USA
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Joined: 08/01/2002
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Give a lot of planning to insulation. Thin walls don't give much space for insulation. While you could make the walls out of 1" steel tubing and it would be strong it would not have very good insulation.
Better insulation will keep the motorhome warmer in cold temperatures and cooler in the summer. Less need for the furnace or the A/C.
With a thicker wall you can have better insulation and just give up a few inches of interior room. But the motorhome will be more liveable with better insulation. Also be reasonable with the size of the windows. Large windows may seem nice but single pane glass only has a R-1 value.
What type of insulation?
Fiberglass batts have the lowest R-value and gets damaged if it gets wet.
Expanded polystyrene - bead board - is used by a lot of RV mfrs because it is cheaper. R-4 per inch. But I think there are better foam choices.
Extruded polystyrene. R-5 per inch and stronger. Dow Chemical's Styrofoam brand is blue. Owens Corning's Formular brand is pink. These are just marketing colors. It is the same characteristics. Available in different thicknesses and sizes. Use a commercial insulation distributor vs a lumber yard or home improvement center and you can even get "high load" versions.
Polyisocyanurate. Polyiso has a higher R-Value, R-6.5 per inch. But is not as strong and if the foil facing is damaged you should fix it with a foil tape. over time it will outgas more and loose some of its R-value.
Foil/air bubble insulation, like the Reflectix brand, has air space requirements that are often not used and therefore does not produce the claimed R-Values. Per the mfr specs you need to leave a 3/4" to 1" air space to get near the R-values claimed. To stack multiple layers you have leave the air space between each layer.
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tonyandkaren
pennsylvania
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Joined: 05/15/2005
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Cool project! Post updates as you build please.
Dakzuki is right about watching your weight. We had a motorhome built for us , same size and basically the same floor plan of our old one but with sturdier materials which was fine because we were going from a Dodge 3500 to a F 450. Anyway the upgraded materials added 2,000 pounds. We're still way underweight though because of the heavier truck chassis.
Look at the materials being used in motorhomes - not very much solid wood except for cabinet doors. Most of the interior walls are 1/8" plywood. Cabinets are just sides and floors. Keep all of this in mind as you build.
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Boujei
Where I am now
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I'll have to do some calculations for weight. I have seen a work in progress where the fellow used standard 2x4 construction vs 2x2. He also used the pink foam board from the big orange store and seems pretty happy with the results..needless to say, but she's built like a house! After seeing all the rot in this beast on tear down, going the metal tubing route has peaked my interest. Being in Idaho..well...let's just say I need to stay a bit warmer than the elk hunter in a nylon tent!.
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1995brave
San Antonio, TX
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boujei wrote:Better than average..just picked up a Millermatic 212 last summer and haven't gotten a chance to play with it too much. You don't think I'd accumulate too much weight going with the tubing?
No, it would weigh about the same if you did it out of wood, maybe a couple pounds more, but a lot safer. If you are really woried about weight you could try your luck with aluminum.
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Quick trip
Cerritos, Ca.
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Joined: 12/23/2005
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I would not use any kind of a camper stove as there is no way to exaust the fumes from the stove.
Good Luck on your project and send more pictures as you do the rebuild!
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snowdance
Yreka, Ca
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I saw one parked in our Walmart a few days ago. It was some what the same idea with a rear drop down door for the ATV/Motorcycles. He said he had ab out 6 feet in that area. Rest was normal Motothome stuff. Most intresting was the bed over the cab was about a foot taller than most and about 2-3 feet behind the cab it came back to a normal height. Talked to the fellow (from Canada) he said the high area over the bed made it far easier to get in-out and make the bed. I too, would love to make my own if I were just a bit younger.. Its a project I would enjoy.. Good luck..
Snowdance
We spent most of our money traveling... Just wasted the rest..
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pianotuna
Regina, SK, Canada
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Joined: 12/18/2004
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Hi Boujei,
The Champion inverter generator would be my choice as it can be paralleled if need be. Added to a good pure sine wave inverter and it would be a hard to beat combination.
Inverter generators do run at lower speeds and save fuel, plus they are pure sine wave. The non inverter generators are not kind to most loads except for resistance (light bulbs).
Regards, Don
Kustom Koach Class C 28'5" 256 watts Unisolar, 875 amp hours in two battery banks 12 volt batteries, 2500 MSW watt inverter.
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magik235
Central Wisconsin
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I have been toying with a similar idea so I will be following your build. I am debating using the space savings for a large propane tank and doing a propane conversion since propane is much cheaper.
1985 Sport Coach http://www.rv.net/forum/index.cfm/fuseac........d/tid/26101292/srt/pa/pging/1/page/1.cfm
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pianotuna
Regina, SK, Canada
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Hi magik235,
Off road propane is cheaper--but on road the tax man wants his bite. Miles per gallon will be considerably lower.
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Boujei
Where I am now
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well...first things are to square away the exhaust system and then run new lines for the fuel tank. (vent is weather cracked)I'll spray the frames to inhibit the rust from forming and then work on framing the chassis to accept the sub-floor.
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