Arches and Beams

There are several ways to keep the outdoors out of buildings. Flat roofs (which are not really 100% flat in most cases), thick layers of brush and small branches to make a dense layer, mats of woven stuff under turf, wooden beams with sod on top (and cloth or newspaper to slow the leaks and divert falling critters), stone, metal over wood and stone . . .

Heavy wood beams on top of heavy structure, covered in thin pieces of wood. That’s what you do when wood is available and needs to last a long time. I’d guess that the core of this Polish shed went back to the late 1800s. The reforestation of the 1800s had made wood more available than it was between 1600-1820.

When wood is in short supply, you build with imported wood, then cover it with plaster and thatch. The thatch weighs less than a tile or slate or wooden roof of the same quality, allows better air flow but retains heat, and lasts for 30-40 years when done properly. A good thatch roof in northern Germany (Schleswig-Holstein in this case) is up to 24″ thick. In the case above, the materials are reeds brought in from the Low Countries and England, since the local reeds are not numerous enough, or grow in protected areas and can’t be harvested in the needed quantities. A wooden frame supports the thatch. Fire isn’t as much of a hazard as you’d think, at least in that part of Germany, because it tends to be wet.

However, since fire was one of the greatest hazards of urban areas in the Middle Ages, those places that could required slate or tile roofs. In the north, in the German lands, Low Countries, and Poland, brick replaced the non-existent stone and very expensive imported wood.

Slate, lead, and copper over wood and brick, with some stone. This is Lübeck, the center of the Hansa trade network, and very wealthy. Fire-resistant roofs replaced thatch at a relatively early date. Brick also took the place of both wood and stone. The large holes in the “spine” of the building on the left are to allow the wind through. The stepped roof lines serve a similar purpose – North Sea winds are fierce when they get going, and there’s not many hills or other things to break the flow of air over the land. Ground floors often served as floodways. You didn’t store or build anything on the ground floor that you weren’t willing to either sacrifice or have get wet. The water came at you from both directions up in this part of Europe.

I mentioned timbers?

Mind your head when you get up, or when you stand quickly near the washroom. This is from an old hotel in Olomutz, Moravia, Czechia. Wonderful place, but not for the tall or forgetful. It had a tile roof, probably synthetic tile because of the weight and because of hail. I was on the top floor because, well, I’m small, can carry my luggage up medieval staircases, and don’t mind hiking up steep and narrow medieval staircases. (The porter meant well, but I was in a hurry and other people needed his help a lot more than I did.)

When you have more wood than you need, so to speak, you can do this:

This is down almost on the Polish/Slovak border, in the mountains. Wooden roof because fire is not a danger, wooden building because wood was cheap in terms of labor and supply both. Cheap being relative, however. Parts of Eastern Europe, like western Europe, had occasional shortages of the desired types of wood, even if wood in general was plentiful to “not scarce”. I couldn’t get into this church because a service was in progress. The interior is plastered and painted.

When we think of wood and timber shortages, most of us think about England and Britain in general, because that was one reason given for sending people to the Americas – find wood. Also, the traditional history of the Industrial Revolution centers on a lack of wood for fuel, so coal came into use, which along with the pump led to the use of steam and mechanizing factories and . . . As always, the story is more complicated, but good building timbers tended to be relatively scarce going back to, oh, the Roman Era. When you build things like:

Another, older church is below. It goes back to the 1100s, although I suspect the roof joists are not that old. It was the the first church in England built to honor St. Olaf, and is in York. It was a parish church, and is still active. The oldest surviving beams below date to the 1400s.

If you can’t afford any of those, or your trees are all too short?

Thatch and turf on turf. It works.

12 thoughts on “Arches and Beams

  1. It is amazing how well all of these people through the ages considered their environment and took best advantage of material that was available in the local area. When I lived in England I used to walk past a house that was having its thatch roof replaced just to watch the progress over the course of a few months in summer; fascinating. Thanks

  2. One has to use what one has (or can make) for building materials. And the inventiveness and creativity are simply amazing considering many of these places were built in the 1400-1600s!

  3. I hope you show your students some of these things. Young people today rarely appreciate the world our forebears built for us, and the difficulties they faced in doing it. They were real people, and faced real challenges everywhere. It is by their success that we are here. I suspect few of us are capable of sufficient gratitude.

    • Oak, live oak, hornbeam (ironwood) once iron tools became a little more common. Chestnut for some construction applications, but “timber chestnuts” are treated differently than “food chestnuts” in terms of shaping and coppicing. Willow and others were used for the wattle in wattle-and-daub construction. Linden or lime wood was used for decorative purposes, as were walnut, maple, birch, cherry, and the like. Oak was the ideal for building. Soft woods such as pine didn’t see as much use if oak could be found.

  4. The terms for ground and first floor become more evident, when the ground floor can get covered in ground left from Lake or River X depositing a load of mud/silt. First “regular or mostly permanent we hope” floor is elevated nicely, probably based on historic flood marks.

    • There are very few cellars on the North Sea or Baltic coasts. Partly because of the types of soil, more because of the likelihood of them turning into in-ground pools when the river/sea came to visit, or if it rained a lot (high water table). The wares houses had a ground floor for deliveries and showing goods, the first floor for living and an office, the floors above that for storage and where the apprentices and journeymen slept.

  5. It’s good to see that the parishioners at the church honoring St. Olaf resisted painting or plastering those beautiful rafters (also easier to inspect)..

  6. I just finished reading a book from 1975,by Jean Gimpel on The Medieval Machine. He discusses finding wood in the 1100’s that is suitable for building because many of the tall trees had been harvested. He discusses solutions that medievals came up with for covering large spaces when the trees were ‘only’ 20 feet tall. He also discusses Abbot Suger finding taller trees for his new work on the Cathedral of Saint Denis. Fascinating.

    • That rings an old bell, but one I recall was The Medieval Engineers (?). Supplemental reading for a class. IIRC [maybe, it was *hrrm* years ago] from the class or the paperback, Oxford College took a novel approach in its construction. They harvested large oaks for beams and pilings, then planted seedlings and saplings in a tended and dedicated grove. In another 900-1000 years, the replacements would be grown to size.

  7. Possibly The Cathedral Builders? I haven’t read that one.
    But would it really take 900 years? And do oaks really last that long? I don’t know.
    I do know that there are seriously different kinds and that white oak lasts 200 years at least in whatever it is used in.

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