08 January 2020

This is a most interesting roof


The image, from the Minnesota Historical Society (cropped for size), shows a man in Waconia, Minnesota in 1885, standing in front of his original log cabin (probably dating from the 1850s, with his newer home in the background).  The article discussed how early settlers survived the cold winter temperatures, but what interested me was how he had assembled his roof.

I'm quite familiar with Scandinavian sod roofs, but this is different - those large transverse logs are not features of sod roofs I've seen.  So I first looked at A Woodsrunner's Diary, my favorite "living history" blog, but couldn't find anything there.  My next stop was Google Images, where various combinations of key words finally yielded this (image cropped for style) -

"The roof employs a “weight pole” system consisting of split oaken clapboards held down by the weight of heavy poles laid upon them.  Nails, which were scarce and expensive in the late 18th century, were not employed in such a roof."
- which gave me a new search term, which led me to another living history site depicting weight poles being applied to a roof -


I found a closer view at a stock photo site which I can't afford to purchase for embedding, with the weight poles secured in place with large rocks.

Logs on the roof explained - but what's the deal with the saplings on the side of the house?  I'm guessing it all comes down to nails, which were a precious commodity for early settlers.  I have read that when pioneers or homesteaders upgraded from their intial hovels to better houses, they would burn the log shanty in order to extract the nails for reuse.

Mr. Peterson in the top photo covered his roof with shingles or shakes (or maybe slabs of tree bark?).  He didn't have the necessary nails to secure each of those, so he placed the logs transversely.  But then you need something to secure the logs.  In the stock image linked above, the logs are secured in place with what look like railroad spikes.  Probably Mr. Peterson didn't have those (or didn't have an underlying beam to drive the spikes into), so he used the saplings at the sides of the house.  But I'm not sure how the saplings are secured in place; they could be tied to the logs with ligatures (leather, root) through the chinks, but I can't see that in the photo.  Perhaps some reader can finish solving the puzzle.

Interesting.  You learn something every day.

13 comments:

  1. how about wooden pegs?

    I-)

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  2. Sorry, I can't help with the question but, as I'm sure you know, but others might not, "Scandinavians introduced the log cabin to America when they settled New Sweden in the area of the Delaware Bay in 1638. In the seventeenth and eighteenth century, German and Swiss settlers brought the concept of the “continental” log building, which was divided into three rooms and organized around a central hearth." https://philadelphiaencyclopedia.org/archive/log-cabins/ Many old illustrations of early Plymouth Plantation (and other early Massachusetts and Connecticut settlements) for many years erroneously showed their homes as log cabins.

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  3. Wow, my parents brought a music box home from Germany some 60 years ago, it was in the shape of a (rustic) house. It has small stones glued to the roof and now, lo these many years on I know why.

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  4. This type of construction was very common in early settlers homes and bush cabins in Australia.

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  5. Likewise it was a standard method of roofing in Japanese domestic buildings for many centuries.

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  6. My guess is that the small poles are pegged to the logs to keep them from rolling. They act like levers.

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  7. The saplings are to keep the weight poles in place. The saplings are likely pegged to the ends of the purlins (the end of which can be seen protruding from the gable end). The pegs were likely made of a rot-resistant hardwood like black locust.

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  8. It would seem to be problematic in climates that have much snowfall, since the logs would, I would think, hold the snow in place (or, for that matter, rain), allowing water or melted snow to have time to find any cracks.

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  9. if you look closely the saplings are all on the lower side of the logs on the roof. they may not be fixed to the roof logs at all and their purpose is only to stop the roof logs sliding off, not to tie the roof logs down. the saplings seem to line up with the timbers underneath the roof sheeting and are probably fixed there, whether by nail or notching or peg or tie. they must also be fixed somewhere else to stop them from moving. the fact that the gable ends of the house protrude would suggest the only likely place the saplings are fixed is at the bottom.

    as Aaron s has commented i wonder how the weight pole roofs worked with rain or snow melt, was tar or pitch in use at this time? maybe they layered enough roofing material so that most of the water ended up outside. does anyone here have any ideas?

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  10. Last Fall the Townsends youtube channel, a delightfully charming channel dedicated to 18th century living history and recipe recreation, built a log cabin from scratch. The playlist for the episodes is here, https://www.youtube.com/playlist?list=PL4e4wpjna1vxWSCj8rNp-c3dDzoHLTItx, but the second one is about the roof. They used bark sheets and a mix of just a few nails, a bunch of black locust thorns, and while they mention a plan to use weight logs, I don't think they ended up using them for whatever reason.

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    Replies
    1. Thank you, Russell. The video nicely illustrates the use of long strips of bark for roofing material. The use of thorns as tools was new to me. But I was most pleased to see the external vertical elements tied in place through the chinks between the logs; I think that must be what Mr. Peterson did on his cabin. And they did add weight logs at 11:05 of the third video (with braces at the very ends of the roof).

      Nicely done videos. Thanks again.

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    2. De nada. It's a really fun channel. I like the history of cooking, so a lot of the old recipes are fun, but what keeps me coming back is just how cheery, excited, and optimistic John the host is. Brightens up our days in these strange times, and thanks to his love of the spice, has now got my wife and I saying "I put nutmeg on my nutmeg!" whenever we grate nutmeg into something. His store is based out of Indiana somewhere.

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  11. Really old houses here in Finland had bark roofs and they were usually held in place with peat. Cabin type "quickly assembled" structures could also have cane (reed?) roofs that had logs on the roof to weigh them down.

    My guess that the saplings are permanently attached to the roof weights for quick (dis)assembly as you need to constantly afjust the roof. Or just move the entire house?

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