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Reciprocal Roof and not-perfect-circle houses?

 
Sahara Sjovaettir
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I was wondering, can a reciprocal roof be used on a not-perfectly-round house? Our house is more.... rounded onion shape, with a single hard corner (to accommodate the bed). It's a uber-tinyhome, more of a studio cob room, lol! It's planned for being about 120 square feet (hence the need to fit a corner to the bed, which is raised).

So, is it possible to make some of the poles longer and some shorter, to fit the house? We can't round the walls out to fit the roof (or we go over the don't-need-a-permit-for-this size), and if we shrink the protruding walls to fit a smaller round roof and stick to 120sqft, well, the bed would have to be in the center and it would just be unlivable.


OR.... is it better to just keep the roof round, and build up the walls in some areas to fit it? I'm just concerned about getting the wall height right in the areas that need it before putting the roof up (or letting some of the poles 'hover' before adjusting the wall height).
 
Len Ovens
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Location: Vancouver Island
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Sahara Sjovaettir wrote:I was wondering, can a reciprocal roof be used on a not-perfectly-round house? Our house is more.... rounded onion shape, with a single hard corner (to accommodate the bed). It's a uber-tinyhome, more of a studio cob room, lol! It's planned for being about 120 square feet (hence the need to fit a corner to the bed, which is raised).

So, is it possible to make some of the poles longer and some shorter, to fit the house? We can't round the walls out to fit the roof (or we go over the don't-need-a-permit-for-this size), and if we shrink the protruding walls to fit a smaller round roof and stick to 120sqft, well, the bed would have to be in the center and it would just be unlivable.


OR.... is it better to just keep the roof round, and build up the walls in some areas to fit it? I'm just concerned about getting the wall height right in the areas that need it before putting the roof up (or letting some of the poles 'hover' before adjusting the wall height).


I don't think there is a reason it has to be a perfect circle, but I do think you want the curves of the roof to be "fair" for best water shedding. That is, if one pole for the roof is longer, then it needs to end on the outside end a little lower than the rest so that at the point where it would be the same length it is the same height as the rest. I do not know if it would be possible (or wise) to tilt the whole assembly in a reciprocal roof as one could with straight cone rafter style, to keep the walls all the same height. Because there is no support in the centre there would be more forces generated on one side than the other. Because it is so small however, this may or not matter. I would think that the poles are 8 to 10 feet and the frame could be built on the ground and lifted... at that point one could try tilting it to make the bottom even and see what happens. If the poles are not joined too tight any swaying or sagging in the wrong direction would show uneven forces. At least it could be test assembled on the ground easily before adding it to the building. Even try modeling it with willow sticks or some other locally available straight stick (your grocer will probably have cheap chop sticks). Use 1in = 1ft for easy conversion. Any drafting store (office supplies or collage book store maybe too) will have a Scale (looks like a ruler) with the inches divided into 12 instead of 8 or 16. I would suggest getting one anyway, they are great for doing scale drawings of room layouts and other like things. Normally they are triangular with 10 to 12 different scales.

(Gotta be careful asking such questions in forums with lots of experimenters, the general answer to everything will be "please try it and let us know how it goes" )
 
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