This is the story of Charles Yeager’s timber frame sauna workshops taught in the Upper Peninsula of Michigan.  The cordwood infill was completed during two, three-day workshops.  The timber frame was erected before the workshops. This is the right (south) side of the sauna. Notice the hollow window logs to the lower right and left of the window opening.

The sauna was built into a hill in the Upper Peninsula of Michigan. Hence the stair-step blocks which go uphill. The back of the sauna and the sides will be waterproofed and backfilled. Notice the sill plates on the horizontal and vertical block surfaces, Since this is a sauna, not a house, there is no sill seal installed. The cordwood is eight inches long as well as the bottle logs. The posts and beams as well as the window box are eight inches wide.  The captions that follow are courtesy of Charles Yeager.  Thank you, Chuck. 


This view shows the front and the left side of the sauna. The front of the sauna is three blocks high. It did not need to be this tall since there is a covered porch, but the blocks in front match the height of the blocks on the sides. Note the tiny logs under the window box. 

Timber Frame built by Third Coast Builders, Marquette, MI

Installing the “key” or “spline” on the beams to give the mortar something to grab ahold of. After the key installation roofing nails were pounded into the key at 4-6 inch intervals, also to give the mortar an additional anchor.

Installing the floating window box to the proper height and to make sure it is level and in line with the posts and beams. The supports are removed as the cordwood wall is put in place.

After the mortar cures for a day, it will be hard enough to support the window box. At this point, the window box supports are removed. The blue painters’ tape was put in place to keep the edges of the window box and posts and beams “mortar-free”.  Notice the two cordwood shelf pieces directly underneath the window box.

This is my sauna. I built it over three years between 2007 and 2010. During the summers of 2006 and 2007, I cut all the cordwood and air-dried it for two to three years. The first winter I  did the mortise and tenon work to create the timber frame. The next summer I cleared a place for the slab, poured the slab, erected the timber frame, installed the roof and inside walls. The next winter I made all of my bottle logs, windows and doors. Finally the third summer, I did all of the cordwood construction (77 batches of hand-mixed mortar), installed the doors, windows, wood stove and benches. All windows were recycled. The stack wall corners are for “show” as there are 8′ X 8″ posts at each corner. The walls are 12 inches thick.  This is the link to the article that shows dozens of pictures of this sauna masterpiece.

Charles has a simple method of making bottle logs that he plans to share with the public later this winter. 

Should you wish to learn how to build a cordwood cottage, cabin or home, please visit   While you are there, click on the pictures, read the brief articles, check out the latest workshops and newsletter and if you are interested click on the Online Bookstore to see all the cordwood literature available in print and ebook format.

If you have questions that aren’t answered on the website you can email me at  

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Readers have requested a brief bio, so here goes:

“Richard & Becky Flatau built their mortgage-free cordwood home in 1979 in Merrill, Wisconsin. Since then, they have written books, conducted workshops, facilitated the 2005,  2011 and 2015 Cordwood Conferences and provided consultation for cordwood builders.  Cordwood Construction: Best Practices DVD (2019),  Cordwood Construction Best Practices 2020 (print), Cordwood Conference Papers 2015 and Cordwood House Plans with 16 different floor plans, are the newest publications available from their online cordwood bookstore.”


To learn how to build your own Mortgage-Free cordwood home visit