DL, wasn't /isn't this building being designed with 'the wheel'? Why worry about math?

Seriously... I'm wondering.

Or are you copying a design with 6' posts and need something that will work?

It is designed with geometry, but not with the daisy wheel. The front elevation was drawn using Ad Triagulum, which is best suited for such and of which the wheel is a form. The floor plan however was drawn using Ad Quadratum, because that works best for floor plans.

All the measurements corresponding to 24", 32", 36", and 48" are yielded by the geometry, I am just trying to decide which one will work the best. So I present the measurement because it is easier for us to understand and because we are trained to think in those terms.

When devising these measurements, I used my dividers and stepped them off to see how well they would work. Then with the ones that did work I measured them with a ruler to find their measure in inches.

Geometry will mostly yield measurements that come out to nice even feet or inches, but now and then there are those oddball irrational numbers...

http://www.youtube.com/watch?v=rql-qKr6T58&feature=related

Just found this, a video of a Fachwerkhaus being put together

Today I began construction of a Tjæremile

A Tjæremile is a Tar making pit (the word is the traditional Norwegian Term)

This style of pit is built into the side of a hill, with a framed pit and a small building projecting out of the hillside. This is just one way to build the pit. Sometimes they are pits dug in the ground by a steep hillside with a pipe run out through the side of the hill to collect the tar. Sometimes they are built half in the side of a natural hill with a complete artificial hill built on the other side. As said, this style has a hut structure built on the downhill side. The structure will be completely covered with a thick layer of dirt, and will provide a platform to walk around an inspect the pit from all sides, which is absolutely vital during firing.

The pit itself will be coated with a thick clay to ensure it is both smooth and airtight. The bottom of the traditional kilns in Norway are covered with birch bark in such a way as to let the tar all run down into a pipe located at the bottom. The wood is stacked in a special way in the kiln as well to encourage the tar to run down to the pipe.

The stacked wood is covered with a layer of sticks, leaves, grass, straw, or whatever and then covered with dirt, sod, or peat to seal it off from the air. A ring is left uncovered at the bottom which is used to light it and control the air intake while firing.

here are some pictures of what I have. I have the wooden support structure nearly completed (worked on it by myself for about 5 hours this afternoon) and it's about ready to be covered over with dirt and the pit coated with a good thick heavy clay. The pipe coming out of the bottom will be a strip of hickory bark taken from a tree I cut this summer, that I could take large sections of bark from. They rolled up into nice round tubes.


making the support frame. all of the wood is cut from within a few hundred feet of where the pit is built. The wood is about all sitting on rocks to prolong the life of the kiln, even though it is only intended to be a temporary structure.


making the pit support structure. It consists of leaning uprights with small willow sticks woven between them. It is REALLY hard to weave a good sound structure that is small and round. But I figured out a good reliable method after a while that worked well, and made a very rigid framework.


top view of the completed pit frame.


front view of support structure with pit frame.


putting a roof/floor on the frame. This is made of several layers of wood. Good, sound, fresh cut wood on the bottom with a few layers of old dead stuff on top. This will be covered with leaves and sticks and then with dirt that will be seeded with grass to form a sod top. It's not meant to be waterproof so much as provide a good framework for an artificial 'ground'
The uprights for the pit will be trimmed off later.


side view of the (nearly) completed framework.

Hi DLB,

I have posted a thread on the Green Woodworker website forum in the UK to try and establish the use of a pit dug into a hillside slope in my woodland. This can be seen at :-

Woodland hillside pit

Your post above has now got me thinking that this pit might well not be anything to do with sawing lumber as previously assumed. Instead, this could well be a small production set up for making pine tar. I have found no evidence of a pipe in the lower part of the pit but since this is currently filled with broken beer bottles and cans this might well be a possibility.

You can check out the full post at the Bodgers website to check out the story so far :-

http://www.bodgers.org.uk/bb/phpBB2/viewtopic.php?f=15&t=1483

Regards

Ken Hume

I saw pictures of the Gardener's Shelter at Cressing Temple in the video at the end of the bodgers link, a geometrical designed building. A nice thread to follow.

Ken, have you dug into the pits to see what if anything resides in the pits? Sawdust, char, pottery remains. I have found what appears to be charred remains of timber logs and pottery in the two pits at my place. The charred poles may just be a stage of deterioration in my case, but pottery for sure. I am calling my pits some kind of storage facility, a root cellar.

Tim

If it is a tar pit or charcoal pit, there should be a a noticeable layer of charcoal somewhere at the bottom. From what I understand, that is how they identify the old pit locations in Scandinavia is by digging under them to find charcoal.

The coal should be more than just some scattered bits and charred ends, it should be a complete layer. When you clean out the kiln after a firing, it is impossible to remove all of the fines and dust, so it gets left behind.

Hi,

here is a little film of how we did it a while back in Sweden. And then some more descriptive pictures of the process here.
though, you know, tar was mostly produced for ship and boat building with maybe some other minor uses on the side like healing hoofs. The timmerman I spoke with in Sweden told me the only thing he knew of it being used for otherwise was sometimes coating the mud sill. I put it on our barn knowing that it is not particularly durable and will require frequent maintenance which I don't mind 'cause I like working with it. I also use it to cover m' shoes

Greetings

Don

Tar was definitely used to cover buildings in Scandinavia during the middle ages, as is attested by the Stave Churches. they are all coated with pine tar, and most are apparently recoated every 10 years or so. Tar was definitely used for boats, and that was its primary use by the 1800's or so. I suspect there may have come a time when people didn't want their houses to smell like pine tar any more, and so its use as a buildings preservative may have likewise died out. There are also buildings from Germany and Central Europe that are likewise sealed off with tar, in fact sealing timbers with tar may be the origin of the tradition in many Germanic regions of painting exposed timbers dark brown (there are a few areas that paint them dark red instead)

Don, the process shown there is a more modern variation. Things I have come across written by Norwegians, Swedes, and Finns who still do this in the pit claim that the pit method yields a higher quality tar than is yielded by indirect pyrolysis (which is what you are doing there) That said, that's still good work, and I'm not entirely convinced (although I do not have enough info to come to an informed decision) that there is any significant difference. From what I have seen, they claim the chemicals present exist in a different ratios depending on whether the wood was burned directly or indirectly. Pine tar burned in a direct burn pit apparently contains higher levels of turpentine, for example.

It is also best to hunt down wood with natural preservative properties to use in the kiln. In the old method, pine trees would be scarred extensively because this causes them to produce a special preservative sap. Nowadays in Norway (since that method is illegal now) they use the roots of pine trees, because they contain more preservatives and more sap, and they are leftovers from logging operations.

Here in Indiana, I would choose wood like walnut, black cherry, locust, mulberry, Osage orange, white oak, and others that are high in tannins or other natural preservatives. The goal is to create a tar with as much chemical preservative as possible, and so the choice of wood is important.

Pine and other softwood tar is high in turpentine, the higher the turpentine the better it is.

Hardwoods tar is instead high in wood alcohol and tannic acid, which are both highly preservative agents. Like turpentine in softwoods, the more wood alcohol you can get the better. Tannin content is related to the wood species, while alcohol content is related somewhat to species but mostly to the process.

It is important to remember that distilled wood alcohol is a deadly poison. However, dissolved in tar it is essentially denatured, to the extent that hardwood tar, like pine tar, is safe to eat (it is the flavoring component of liquid smoke products) and is safe to apply to your skin (hardwood tar is supposed to be an effective remedy for psoriasis, which due to the fact that nobody makes it in large quantities it is replaced in this function with coal tar produced as a byproduct of coke manufacturing)

I would like to get my hands on a large quantity of rather sappy pine (which I'm just not going to get locally) to make some pine tar to compare with hardwood tar.