Putting Passive House to the Test! Pt. 5 - Sizing the Passive Bunkhouse

This has been an interesting week.  I attended a WUFI training session in Seattle and I was able to show the Passive BunkHouse project to two WUFI experts and get their opinion on some materials and monitoring aspects.  Their input was invaluable.

I already have the basic design.  I also have some better ideas for the materials that I want to use.  The input I got from Andre DesJarlais, the WUFI instructor and Group Leader of the Building Envelopes Group at Oak Ridge National Labs was that I was looking at a very wet location and should avoid wood as much as possible.  Barring that, I should monitor both sides of any wood I put into the project to see how it will hold up. 

I asked him if he thought there would be a need for mechanical dehumidification and he thought there might be if I don’t use air conditioning.  I will have to run my design through WUFI to see how it does in that regard as well as the PHPP for the energy design and THERM for help with any thermal bridges.

Andre also said my idea of using different constructions for each wall of one of the outbuildings wouldn’t yield the right kind of results due to the size and location.  He recommended that I choose one wall type and if there is another type I would like to test, to make that a small 4x4 area so that the bulk of the testing could be compared to the other outbuilding that would be made all from one system.  I like that idea and since I want the information that comes out of this project to be very useful I will go with that.

Achilles Karagiozis, WUFI Instructor and Global Head of Building Science at Owens Corning was also interested in the project.  Owens Corning has taken a keen interest in Passive House construction in the US and is working with Passive House Institute US to strongly promote its use here.  I will be sending him additional information on the project.  Both Andre and Achilles will also be good resources to point me towards the type of testing equipment that I should be looking at.  Their interest was quite encouraging and I am excited for the project all over again.

This week I also stopped into Freeway Trailer sales in Milton again to see if I could get some definite dimensions on a trailer in the range I was looking for.  Unfortunately I was putting the cart before the horse.  They need my design of what it will carry in order to determine how the trailer will be built.  So, back to the drawing board.  Collin at Freeway Trailer sales was able to give me some rough rules of thumb for the design weight and that will be further fine tuned as we get to the final design.  For now I am working at a very rough idea that 40% of the weight of the trailer will fall from the center of the axels towards the back and the other 60% will fall forward of the center of the axels.

So now I will be drawing up the plans to a closer scale and figuring out the weights of the materials.  I will be choosing the materials for the first design to be sent through WUFI and the PHPP and next week you will get to see how that design played out in the software and hear what needs to be changed and how I will address those changes.  For now I will stick with the original size of 28 ft long, 8.5 feet wide, but will adapt the design to take into consideration the wheel wells so that I can build closer to the ground and gain more height inside.

Next up – the first test results.  How close do I get the first time around?