Putting Passive House to the Test! Pt. 2 - Designing the Passive Bunkhouse

Just as in regular home design, a recreational vehicle trailer needs to be designed to fit the needs of the occupants.  When designing one from scratch you also need to take into considerations the rules and regulations that will govern the safe use of that trailer.

As part of the design of the trailer I will be talking with the proper Washington State agencies that oversee trailer creation and licensing.  I have purchased the latest code book for recreational vehicles, and will be referring to that for the plumbing, electrical, and fire codes that will dictate how the design goes.  Beyond those considerations I will be looking at materials, weights, and structural integrity.  I will run the design past a structural engineer to see if there are additional measures needed from their perspective.  Eventually I get to the pretty part and look at fixtures and finishes, but those decisions are a bit down the priority list right now. 

I have done some preliminary research into the road rules for a recreational vehicle – it can’t be wider than 8.5 feet and taller than 14 feet.  There are length rules that I won’t need to worry about because I am not building something extremely long, but if you decide to, do look into that.  I know the WSDOT (Washington State Department of Transportation) will be one of my next stops to get all the steps they need me to take, but first I wanted to have a preliminary design to show them.  I figure it wasn’t necessary to start the discussion, but a drawing might trigger additional information and thoughts that might not be there if I just walked in with a “I’m building an RV – what do I need to do?” question. 

My design criteria was that the RV had to be smaller than the 52’ mobile home that currently is on the lot.  It is a very tight lot and I want to have room to park on the lot and not at the road.  I also didn’t want to have something unwieldy to tow.  Finally I wanted to see if I could design something that was in a fairly common travel trailer size bracket and if it could end up meeting the Passive House requirements.  I have not run any simulations yet so it will be an interesting experiment to see how it performs. 

While looking at different design possibilities I came across a very interesting website about a RV park model product called the WheelHaus http://www.wheelhaus.com/. (Which reminded me of the Rolling Huts that OSKA Architects designed http://www.olsonkundigarchitects.com/Projects/825/Rolling-Huts#) They both have a way to make a small place seem large and provide a lot of light.  Since pointing that large end window towards the lake would be ideal for a view as well as Southern exposure, I knew this was the design I wanted. 

About the same time I saw the WheelHaus park model I watched a documentary about designing an extremely tiny apartment.  One of the things they mentioned was that in order for a tiny apartment to not feel tiny the ceilings had to be at least 9’ tall.  When I heard that it made the WheelHaus idea click – that ceiling was not only really cool to look at, it would make staying in a small RV so much more enjoyable.  With that in mind and the knowledge that I could have an RV 14’ tall I came up with the following 200sf plan. 

Because I don’t have the exact dimensions of the flatbed trailer this will be built on, the ceiling heights are all rough estimates.  I will take the blog on a field trip next week to visit a trailer sales lot to see the different options I can use as the foundation for my new RV.  There will be pros and cons for the different styles, just as there are for regular home foundations.  Ultimately the deciding factor will be what can give me the most room, but still allow for holding tanks to be placed to code underneath.  Once I have decided on the trailer the design with material selections can begin and I can also talk to the state about their requirements.

But first one last thing to take care of – what to call an RV built to Passive House principles?  I thought I would tie the new trailer into the history of the lot it will be parked on.  One of the buildings that will be removed was referred to as “the bunkhouse”.  When the family would come to camp they would stay in the Mobile Home, but the boys got to camp out in the bunkhouse.  The idea of having an actual bunkhouse made me smile when I first heard it and I have decided that this project will be called the Passive Bunkhouse.

Up next – Road trip to check out trailer styles.