There are two components to the roof on a yurt. You have a roof ring and rafters. Like all yurts, there are many ways to build one, and most of them work fairly well. You can go for a large diameter ring or a smaller diameter one. The diameter of the yurt and the length of the rafters both factor in to the ring size. Another thing to consider is that the larger the ring diameter, the more rafters you will end up with.
When choosing your design, roof pitch is very important. The steeper the roof is, the faster the water will run off of it, giving it less time to soak through. All canvas will leak if it stays wet enough for long enough, so you don’t want your roof to be too flat.
When I set up a yurt, I usually shoot for at least a 3 foot rise on a 16 foot diameter. Anything flatter, and you are asking for leaks.
You can make the ring small, about 30 inches across, or larger, I made mine 42 inches. There’s no right or wrong answer here. Roof pitch and rafter length factor in as well. I try to keep the overall rafter length to 8 feet or less, since 8 foot lumber is easy to come by.
One of the biggest mistakes that I have seen in yurt design is not setting the rafters deep enough into the ring. If the rafters are too shallow, they can fall out, especially in a storm, causing the whole roof to collapse. I have even heard of the ring spiraling around and falling in.
To figure out the roof ring size we will need, I will go with 8 foot rafters for the 16 foot yurt. Subtract 4 inches to allow for inserting one end in the ring, and the other end hooking on the walls.
96 – 4 = 92 inches
We will go for a 3 foot rise (36″) or higher in the ring from the top of the walls.
First we need to calculate the difference between the diameter of the yurt and the ring.
Let’s start with a 36″ diameter ring and see how much of a rise we will end up with.
The diameter is: 16 x 12 = 192″
192 – 36 = 156
156 / 2 = 78
= 48.78 inches rise
This is a nice steep roof that shouldn’t leak too easily.