|Ragnar's Eco-Cabin Weeb Site|
|Let's Build an Eco-Cabin|
Well the first thing we learned is that The Original Eco-Cabin Book is not perfect. There are many important things you will need to know that are not covered in the book.
The model was a great idea, it was built to scale and so we could take measurements off it. there are some pictures of the model in the Picture Gallery. If you don't build a wood scale model you should atleast build one of the paper models from the original book.
The single greatest problem with the book was that it was written in a very different place and very different times. Written in the late 60s early 70s based on the experiences building on Vancouver Island, a lot has changed in woods in those 30 years and in Ontario the weather is different. The original cabins were built of shiplap lumber in a forest rich zone it was cheap then, now it's not. 2x4s aren't 2" x 4" any more. There are many newer and stronger materials to build with, and that is well illustrated by spacific isues around the tools and Materials you'll need.
Tools are very important and you are far better off to get good ones, rather like shoes.
For the Cabin ReBuild Mom and I went out to the Home Despot (not misspell it I did say despot) where we did get a bretty good dealon this whole set of Ryobi cordless tools. They all use the same battery packs so we can charge them when we go home and they all work together. We're going to do a lot less by hand this time. These will help a lot though.
It might nice to do the sheathing with lumber but you just can't anymore there aren't any trees left for that, but it's alright to use plywood or chipboard we did and I think it worked out better.
For the new cabin I've changed the foundation a lot, I was thinking about the Icosahedron and how strong the triagles are and I figure that the triangle wall frames can and want to hold and transfer the weight of the roof down to the ground. So we have sunk foundation posts as deep as we could and positioned them so there is a post under each of the five corners. This time the cabin is goinf to be as solid as I can make it, now the last ime the floor was holding a lot of the wall and susequently roof weight, but this time there are four posts sunk in the middle of the five corner posts and teh floor is just giong to sit on them. This way the load of the roof will be transfered stright down to the ground and the floor won't have any other loads on it, cool eh?:o)
The insulation went in quick and easy too. We did however have to build the tougne and grouve plywood layer twice, once under the floor frameand again on top, this mad for some fun and humourous times nailing up and crawling under the floor, but we got it done.
The new floor will be built pretty much the same way, we'll still use the two "skid" beams underneth but since most of the load of the cabin will be on the corners they're really only ther to ensure that the floor is stable enough to keep the tiles from buckling. I toyed with the idea or builfit the floor in a radial way or even in five triangles with only one post in the center of the outer five but that would have been far too over enginered for this little thing, remember the pentagon floor is 14 feet at the widest outside measurement. I would do the floor this way if I were building a much bigger one, and I'm thinking about drawing up some planes for three story variation on this one that would be almost three times the size, it would cost a lot though. I also considered building the floor slung between the five posts and hanging from the walls, the Icosahedron can let us do that easly and it would be nice to have a nicly spung floor, but not with ceramic tiles on the floor.
Because of the angles involved with the hubs the bord nailed into the floor should be cut at the same 65° angle as the hubs, were they meet the floor. How ever it should be noted that eventhough these hubs work fairly well on the floor the hubs at the top of the walls are very dificuld to keep from twisting and deforming the traingle which is what the whole point of how this structure works.
It was my intention to eliminate the hubs in this new cabin, by building the framing of real triagles. By miter cutting the right compound angles on the ends of all the struts they could go together to form true triangles and will form-up perfectly. There will need to be strust on the bottom of the walls at floor level so we'll need more 9' 2x4s, not a big problem concidering how much stronger and easier it will be. I do think that some kind of device will be needed to hold the five struts together, but at least structurally it will be more stable, because they will be triangular. The old cabin with the hubs made a situation were what should have been triangles were hexagones and as the hubs twisted the triagle deformed. So were there were suposed to have angles of only 60° they were from 57° to 64°. The incredably iritating effect of this was that none of the walls was the same, we couldn't make the same cuts on all the peices of sheetboards we used for sheathing. Without the hubs, as long as the struts are the same length we will be sure of having true equalateral triagles and all the angles will be 60°. Now we can just cut everything the same, I like that,:o)
When you get to putting the roof struts in the top of the wall hubs use the pole cut exactly 137 3/4 inches long. you should mark perpendicular lines every foot on what will be the underside of the roof struts. Use these lines when positioning the struts in the slot in the hubs. Adjust them so all the hubs are at the same position on all the struts, then they will be evenly spaced. Now this can be more easilly done by cutting all all your hubs as the top roof hub and
One thing that you should concider in building this kind of structure is that it has no right angles, I decided to fix that by putting a 72° rip cut board on both sides of the struts, see Walls for more on this very helpful sollution.
For the framing of the new cabin we'll be using a basicaly hubless design, we'll build an icahedron for it's strength and then for the roof and eaves we'll lay another board on top of the roof struts extending out beyond the wall to form the eaves. This will also give use a much thicker roof making it a lot easier to insulate the roof, which I'll expand apon in the Roof section.
The new roof is going to be compleatly different from the original. It'll be properly insulated and vented so there will be air flow between the insulation and the sheathing with the shingles nailed in. This air flow prolongs the life of the shingles.
To deal with the compound angles for framing the studs and such in the walls, I developed this funky thing to give the hole wall more right angles. We had to rip cut some 2x4s the whole length at a 72° making a wedge that we then nailed to the sides if the struts thus eliminating one or the angles that we would have needed to deal with. Also it made all the walls like a traiangular hole with strait sides so the top of all the plumb stud could be cut at 30° and the ends of all level boards cut to 60°. It may help you to look at the 2nd Build Session Gallery
I found that insulating was easy, though I'm sure it helped that we basically framed all the walls with 2x4s on 16" centers so we just baught all the right supplies for standared
We desided to have a lot of windows for the light and the view so a lot changed from the original book version of the cabin.
In the new cabin we're going to have bretty much the same window arangements.
I had wanted to build a drawbridge like door built with steps on the inside so when in the lowered position it would be the stairs up into the cabin. I think this would be the only way to have a flush mounting door to the wall, but the door would take a great deal of abuse being the stairs and if it was to drop or fall it could be damaged.
The door for the new cabin will be mostly the same as the first. One difference will be to build the lower part of the door frame in the wall as much as we can or even extend teh floor out a foot I'm thinking too of building some kind of remoovable storm door that will mount flush with the wall when we're not there.
We desided, As I think everyone should do, to keep as much of the floor as open as posible. So the only things on the floor are the stove and the benches/beds. I designed benches built on to the walls oposite the door, they are plywood supported by ply-wood legs to form boxes under to put rubermade totes in. The benches fold out into the room to form 3foot wide platforms for beds, and the fome matresses are cut lengthwise to also make cusions on the benches. The fold out sections are supported in the out positions by removable legs.
One thing you'll need to think about if you do build fols-out benches ist the the corners of this building are not normal. We built the benches to meet in the corner oposit the door, this gave us a a big triangular hole for storage in the corner but it needed to be covered so the dog or cat wouldn't fall in it when sleeping on the beds. However you can't build square fold outs, especialy in that corner because the angle at which they meet, so you need to cut that end of the fold out at 54°, or slightly less, so they will lie flate when open. but this works well with the mattress because the wall has a 60° angel so the bench back cusion should be cut at that angel to fit the wall and the fold out, cool, no?
In the new cabin the benches are going to be built lower and deeper. they were 16" with a 17" fold out, this time they will be 2 feet deep designed to acomadate the 24"x12" rubbermaide containers, and with an 18"ish fold out. So the benches will use more floor than the first one but the greater convienence will be better because the you'll be able to rest on a 2' wide bed and the benches with the matress cusions on will be a lot more comfortable, as well as having more storage space onder them too.
Jøtul F 100 Nordic QT is a great little wood burning stove, this was what we had in the old cabin and we'll get anoter one for the new cabin.
The original stove pipe went out the back of the stove and right out the corner wall of the cabin to a chimeny that was all outside the cabin. We did this because it was easy and this way the stove pipe wouldn't be in the way inside. However in the winter the cabin was slow to heat-up because the stove was exsausted right out the wall. Also it would get cold soon after the fire burnt out. We found that we rarely used the top of the stove and we could still see the stove pipe chimney through the window anyway.
The new cabin, the stove pipe will come out the top of the stove and and then move along to the peak of the roof were I'll be building the chimney. This will ceek the heat in the cabin longer and I think the cabin will look better with out the shinny chimney beside the door.
© Ragnar Torfason|
2006 May 8