Matthew Burke

Thank you everyone for your thoughtful suggestions. I'm going to try to wrap my brain around it all and get to action!

I used a circular metal center ring designed for yurts.

It has 8 spots to bolt in rafters (I am using 8' 2x4).

The span at the end is quite long - roughly 72" (6'). This is causing the plywood sheathing to dip in the middle as shown in the picture.

How much of an issue is this over time? I didn't want to use thicker plywood ($$$) or braces from the rafters but I am not sure how else to make this a bit more sound.

Thanks for any suggestions. Many learning opportunities here...

Thanks for the advice and will do

Thanks John! I'm hoping with some regrading and a proper roof overhang, there won't be much water getting in there.

Good Afternoon!

I started laying the foundation with gravel as rubble trench before placing urbanite. Due to the site location, I was not able to install drainage. With a lot of rain, the foundation (heavy clay soil) flooded/pooled and the gravel is now intermixed with clay mud. Is this "dirty" gravel still acceptable to use as the rubble trench?

I have since removed the gravel and put in posts which I was not originally planning to do. Upon completing the roof, I will tackle the foundation.

Thanks!

It will be close but I believe manageable. Thanks for presenting that as a possible hinderance

Thank you everyone for your replies!

I am located in the DMV area of Maryland - Zone 7a

The interior of the cob structure will be 6' dia.

The roaster dimensions are in the attached photo

I plan to be roasting about 1.5-2 hrs per session. Initially only once per week.

I am uncertain as to how much heat it puts off but I don't believe much but I'll only need it to be heated while I am actively using it. I'll have to inquire as to the head output - it would be nice to not need an external heat source.

The cob shed will be roughly 6' diameter and will hold a 1lb coffee roaster, vented through the wall. There will not be room for much else other than operation.

Heating options: Since this is such a small space and one that already has a propane-fed machine I am concerned about putting in a wood stove. Are there any options for a fire outside of the structure that heats through to the inside? Any other suggestions? Thanks!

@John - thank you for breaking down the math for me - much appreciated. I'll head out when it stops raining and measure or dig up some more

@Glenn - I suppose I'll put a few samples in a jar and really see about the soil itself, but based on looks and feel, is quite heavily clay based. Where you mention organic litter, I was chopping wood there. I have started to sift dirt with a 1/2 inch screen at the second location to get out some of the rocks, roots, and other organic matter. I picked up some play sand for a firepit and was hoping to mix it in with the soil along with straw.

I was also debating straw bale if the consistency or amount of clay soil was not correct.

I appreciate all of your responses and the help!

Good Afternoon!

I plan on making a circular COB with an eight foot diameter, stone footings, glass bottles, and at least 1 window, uncertain of the height (I am 6" and will want to stand up of course).

I know there are may be other factors involved to get an adequate answer, to which I can add more details to this post, but I am wondering if I will have enough clay soil? I am having a hard time looking at the volume that I have and picturing how much will go into the project. This will be my first venture into the cob - thanks for your support!