My RMH bench is my bed. The first year, I placed cotton bags full of buckwheat hulls tied together directly on the bricks of the bench. The next year I decided to experiment with hemp 'sand' and natural latex chunks instead. This time I went with a recommended frame, because the cotton bags had moved around too much on their own. Probably should have just built a frame for the bags, but figured I'd have a second bench soon and would use the opportunity to experiment with a new frame then.
The frame is just pallet wood slats with an inch gap between them. The slats run under the side support boards so each gap becomes a channel to radiate warmed air off to the side. An inch seems good spacing to allow flow while keeping the bedding from sinking in and blocking it up.
The cotton bags and buckwheat hulls are 100% organic, as are the hemp sand (hulls) and latex chunks, and all were purchased from
Open Your Eyes Bedding (Lynne is a fellow Permie here). The hemp and latex were put in a 3" topper case from
Amazon. Lynne said they normally recommend a 2" topper full of the hemp on the bottom and a 1" topper with the latex on top, but that they might mix fine in a single sleeve and had been meaning to experiment with it, so I decided to save the cost and go with a single. I have found that with the mix the latex floats on top and migrates away as I toss an turn in bed.
I'll experiment with fill levels also when I have time- there is an art to bedding like this. Despite the temptation to 'tweak' the arrangement and a bit of fussiness over how the materials sit, they are insanely comfortable. What had become chronic back pain for me like five years ago has all but disappeared since adopting these materials. It might be from general permies lifestyle changes, but when I sleep in a guestroom somewhere else the pain tends to return. I've heard mention of "grounding" in conjunction with these materials.
I should also mention that this bench is in a Yurt I use all winter. The hulls and latex have done an excellent job of tolerating the heat and passing it through to the top. Some nights when it has gotten to -30F outside and slightly below freezing for the inside air temp, the bench has remained very warm to the touch all night, and very comfortable on top with a sheet, wool blanket, and conventional quilt- the feather bed topper was too warm to ever use this year, except on returning from trips when the bench was not fully heated before bed time. Also also worth mentioning these materials have very rarely been found to trigger allergies and the rodents that have been exploring the yurt and avoiding traps have not shown interest in any of the materials, not even with the bags of excess material stored in the sheds where the little buggers hang out more. If you explore the OYEB website Lynne describes how she evaluated her materials in great detail, including experiments with flammability (hint: amazingly fire resistant, even with government certification tests).
Back to Tiffany's bench- if you are able to order from OYEB or find something similar, construction is modular. The materials can be used to make any size or thickness desired, particularly if you sew your own. I don't know how much hotter your bench might get than mine, but wood with air channels that will be kept open should not cause a problem. For extra peace of mind, the 'cookie rack' effect could be obtained from an old futon frame. In the university town I had been in, at the beginning and end of every school year the curbs were littered with old metal frames like this that no one wanted. I'm not sure the spacing between the metal slats would be sufficient to fully support this type of mattress material alone, but with pallet wood like I have laid across the metal frame I think that would assure flow and spacing to protect the wood from being stressed by any heat the bench could put out...