Insulation to meet code

[Heather V.]

Hi all,

My husband and I are going to go the yurt route! We want to build a house eventually but plan on living in the yurt for a few years before and during the project. We spoke with the local building inspector and his biggest concern was the insulation. Code says the walls have to be R21 and the ceiling has to be R49 (!). We are trying to figure out a way to add the insulation without taking away from the structure. We would like to put as much of it between the cover and liner as we can so it doesn't make our space smaller or cover the lattice(although we are prepared to cover it). If we use fiberglass and put it between the rafters it will make the ceiling almost a foot shorter! The trick is we have to have a material that has a stated R value. I saw the post about ethafoam and it sounded great because it hold its shape well but I couldn't find its R value. Any suggestions are greatly appreciated!

 

[Bob Rowlands]

49 roof and 21 wall, huh? Hmmm. Well I just did a quick search online and ethafoam R value is 2.5 per inch. You'll need 20" of ethafoam dome on the roof and a 9" ethafoam belt on the wall to satisfy the local building gurus. If you build that you might consider giving the Guiness book of records a call.

I suggest setting up a meeting with the local building dept. on your yurt project. Lay out the plan you like which features a reasonable insulation package for a typical modern American residential yurt built for cold climate. I'm sure a couple of the sponsors here offer such a package if you'd care to contact them for details. If the local building intelligentsia lol won't agree to that, forget the yurt idea and build a nice small home. Good luck.

 

[Heather V.]

Clearly ethafoam is out, but there are other materials with a higher R value per inch I'm still considering, I'm just hoping to hear of creative ways to get that insulation into a yurt. Any home in this area will have the same insulation requirements. Its designed to to keep the resident warm without leaving a huge carbon footprint, so I dont plant on contesting it even if I thought I could win.

 

[Jafo]

I am not sure about your plan on putting it between the cover and the liner. There is a lot weight on the liner before you even consider snow. This would compact many kinds of insulation and therefore lower its R value. Also, there is not a lot of room there, because the fabric needs to go over the top edge of the wall lattice.

 

[hierony]

Here's what looks like a good synopsis of insulation materials--if you want a thinner layer, look for materials that have a higher R-value/in. I'm tempted by mineral wool (3.5 R/in or so) though that'd still be 14" on your roof.

What kind of yurt are you looking at? A lot depends on that.

Depending on how your yurt is built, you might be able to find loopholes in the code--look carefully through the definitions (my favorite: 'building' is permanently attached to ground, 'structure' is not--no mention anywhere of a 'structure permit'; don't know if building dept would buy this though...).

Depending on your location, you could build a small building for electricity/water (120 sq ft or less usually doesn't require permitting), get a small beater mobile home (different codes apply); once that's done, setup a yurt inconspicuously and use the trailer for storage/guests while saving for/building your house?

 

[Bob Rowlands]

Let me tell you about regional. If the regional building dept. is involved in your project, be assured you will be paying them alot af money.

Up front fees are generally quite substantial, and you'll probably get some red tape building anything different.

They'll even charge you a 'trip fee' if they show up on site and the person they are there to meet doesn't show up, or the work isn't completed to the stage where they can inspect it.

Plus, you'd best have the permit in plain sight, or there will be a 'fine fee' for that as well. They aren't going to look for it. That's regional in action around here.

Residential subcontractors regularly show up for work and the owner isn't there, the builder isn't there, the super isn't there, and/or the job isn't ready. It's up to you to figure out the job yourself. If you charge a trip fee, they'll sat 'what's this' and laugh at you.

But regional can get away with the charge. Plus make you jump through hoops and delay your progress, because they's 'da man'. lol There's no competition dogging their heels.

 

[Asheville Yurt Company]

The standard foam used in spray on insulation is an isocyanate closed cell foam which has an R value of 6 per inch when aged a bit. It's the highest R value that I know about but isn't what you'd call eco-friendly exactly, except that we figure you save more in energy consumption than you cost the planet producing the stuff. There are some soy based foams that cut it down by 20% or so but they still use the isocyanate as the base insulation material and are much more expensive.

You could put 8in wedges between your rafters but the walls are another story. if you want to see your lattice you'll need a whole new shell or have one made custom (which we could do btw. ;-) )

You might also consider a hardshell yurt as your home if your current budget allows for it. They run the average stick built home prices per square foot.

Nate