Timber Framing: The Old with the New

The structural core of the new SESE headquarters is a timber framed skeleton.  Timber framing is the traditional method for building in wood, only being replaced by modern stick framing in the early 1800’s when the development of industry made the cheap production of standard size wooden lumber and pounds of cheap nails possible.  Timber framing, in a relatively well forested area such as our own, makes the use of local wood, even wood from our own land, possible.  We decided to incorporate timber framing into our new office for a few reasons.

  1. We want this building, SESE’s new home, to gel with SESE’s emphasis on regional heritage and empowering people to provide for themselves and their local communities.  Timber framing in this case allows us to use local wood milled by local millers to build something showcasing a bit of regional building heritage.
  2. The large posts and beams inherent in timber framing allow for large open spans between horizontal posts which works particularly well for straw bale walls.  This is because the posts can be embedded within the straw bales with a minimum of notching of those bales (we only have to notch every 12 to 16 feet rather than every 16 inches as we would with a stick frame).
  3. Exposed timber framing is not only a functional part of the building’s structure but is also quite beautiful and visually impressive.  And what, after all, is life without beauty?
  4. It looks like a lot of fun to build!
The timber frame in progress…

So we dived on in!  Based on a number of recommendations we got in touch with George Allman of Timbersmiths, Inc., a second generation timber framer who lives and works about 30 miles away from us.  He was and still is a great help as he is both an experienced timber framer and a professional engineer.  So, he was able to take our architect’s drawings, confirm their structural soundness, size all our timbers, and provide us with all the diagrams and plans we need to construct the thing in addition to advising us on tools and strategy, loaning and renting us specialty tools, and teaching us all the necessary skills.

So what’s involved?  Well, there are a range of timber framing styles (most countries have their own traditions) and a range of techniques ranging from round timber framing to square and from all traditional hand tools to the inclusion of modern power tools like sliding vs non sliding compound miter saw.  As this is our first timber frame structure we chose a fairly simple style and are using common woodworking power tools (like power planers and circular saws) instead of sweating it out with axes and hand saws.  The modern world has a lot of very useful things to offer us, after all.

First, we ordered our full complement of oaken posts and beams from local sawyer Mike Wheeler and had them delivered to George’s shop where we showed up in force to run them through his giant thickness planer, reducing them all to a uniform thickness and smoothing out the rough saw marks.

Running an 8″x8″ timber through the thickness planer. Look at that plume of shavings!

Once that was done, we loaded the planed timbers onto a flatbed truck and had them delivered to our farm where we set up some heavy duty saw horses and got to work cutting the mortises and tenons needed to join them.

Some of the bigger and more complicated posts required quite a bit of work chiseling out the joinery on their many facets.  Tip: Avoid non-right angles when building a timber frame structure.

The author carving a mortise on the biggest most complicated post in the building.

To increase the drama (and hide the heavy wear likely to happen in the building) we decided to ebonize all the oaken timbers.  Ebonizing is a natural finishing process we learned from a local furniture maker.  Oak, it turns out, is full of tannins which will darken to near blackness when exposed to iron oxide (better known as rust).  Being a working farm we have no shortage of rusty iron and steel laying around which we collected in a bucket and submerged in white vinegar.  Painting this on to the timbers turns them from a golden tan to deep blueish black in minutes.  Very dramatic indeed!

An ebonzed timber next to an unfinished timber in our work yard.

After this we put a final coat of boiled linseed oil on the timbers and lift them into place with the boom truck we are renting from George.  Traditionally the building would be built on the ground in sections called frame rows (basically cross sections of the frame) and then tilted up into place and connected to each other.  It requires a lot of people, a lot of rope, and a pretty good idea of what you’re doing.  As cool as it would be to have a big barn raising, considering the realities of the situation I am incredibly happy to have a crane on hand.  Individual timbers in this building can weigh close to 1000 lbs.

Sliding a girt into place with the help of our borrowed crane.

Once the timbers are placed we drive a peg or two through the joint, tying the tenon into the mortise and securing the frame in place.  Voila!

Foundations: Researching our Options

When I first joined the team designing our new office, there was so much to do that I had no idea where to start. Being a literal sort of person, I decided to start from the ground up: the foundation.

Through this process, I learned some basics about concrete in general. Between mining the raw materials, transporting them, and kilning them, concrete has relatively high embodied energy. For each ton of concrete produced, approximately one ton of CO2 is released. Global demand for concrete is also colossal: 1.6 billion tons annually, with demand rising steadily as more and more countries incorporate concrete into industrial and residential construction.

Click here to read more about what I learned and what we decided to do.

Garden Planning for Seed Saving

by Debbie Piesen

Garden planning can be a complicated business. But for most home gardens, your main concerns are fitting everything in the most space efficient way, rotation, and planning for succession planting. These factors are covered by Southern Exposure’s Garden Planner, a very useful tool for the small scale home grower.

When we start to scale up to a larger garden or farm, however, there are more factors to consider. Is the texture or fertility of your field(s) better suited to particular crops? For example, you might want to plant un-irrigated crops like field corn in a low lying field, where the soil stays moister naturally, or make sure heavy nitrogen feeders follow a successful legume cover crop. You may need to think about truck access for heavier crops like watermelons, and try to match your cultivation techniques to your weed pressure (for example, no-till methods don’t work as well in areas of where you have a lot of aggressive weed seeds in the soil, or perennial weeds).

All these considerations and more need to go into planning our seed growing fields at Living Energy Farm. When growing crops for seed, we also need to plan for isolation distance, to prevent crossing different varieties of the same species; and population size, to ensure enough diversity to maintain genetic vigor. These two issues are related. Generally, some plants are self-pollinated, and will happily pollinate their own flowers, and some are outcrossing, meaning they will hold out for pollen from another plant before setting fruit. Certain self pollinating plants like tomatoes and beans only need an isolation distance of about 50 feet for home scale seed saving. Because these plants mostly pollinate themselves, ten individual plants should be enough to maintain genetic vigor, although you may want to start with more if you plan to do any selection. These are good crops for the beginner seed saver. (To make things more complicated, there are some crops, like okra, that will readily outcross if given the chance but can also pollinate themselves. There plants need an isolation distance of a half mile, but don’t need a huge population size to save seed.)

Plants that outcross by wind or by insect pollinators include corn, members of the cucurbit family (squash, melons, cucumbers, gourds), beets, celery, and members of the brassica family (cabbage, broccoli, kale, kohlrabi, turnips, radishes). Generally, these crops need a population of around 80 individuals to maintain vigorous seed. (Exceptions abound: corn needs about 200 individuals, and cucurbits are not particularly susceptible to inbreeding depression, and can get away with 10-20 individuals). These plants require a minimum isolation of a half mile to ensure pure seed. This kind of isolation distance can be tricky to maintain. Be sure to talk to your neighbors. If you have a neighbor who grows a garden with outcrossing crops, you may want to offer them some of your seed so they will grow the same varieties as you.

If you must have two varieties of the same species closer than a half mile, here are some tricks of the seed saving trade that can cut down on minimum isolation distance. If you plant in blocks instead of rows, and only harvest seed from the middle of the block, this can help maintain pure seed. This method is especially effective with corn. Physical barriers such as rows of trees or buildings will reduce crossing to some extent. The use of barrier crops is effective with insect pollinated crops like squash. A barrier crop is a plant, like buckwheat, placed between your seed crops and timed to flower at the same time as your seed crop to distract the insects that might be flying between your fields.

We have also experimented with time isolation. This means to stagger planting times so that your varieties bloom at different times and cannot pollinate each other. This can be tricky, though. Most plants grow much faster when it is warm, so late planted crops can often "catch up" with early plantings as the weather warms up. A gap in planting time of three weeks can end up with a gap in flowering time of one week or less. But this technique is worth a try, especially for home scale seed saving where a minimal amount of crossing might be acceptable.

Planning a garden for seed saving sounds complicated, but the rewards are abundant. Start with an easier crop like peas or tomatoes and work your way up. Use resources such as Organic Seed Alliance Seed Saving Guide and the Saving Our Seeds organic seed production manuals.

Good luck and happy spring!

Saving the Past for the Future