Restoration of the Roof System on a Corn Crib

Featured

Here at Green Mountain Timber Frames, we have spent the last couple of days working on repairing, sorting, and preparing the roof boards for a little corn crib for sale that dates to the 1800s. corn crib for sale_Vermont Timber Frames

This homemade corn crib was used by a local farm family for generations. We purchased it and took it apart carefully because the sills were completely gone and it was beginning to settle back into the earth.

A future blog will get more into what makes this corn crib really special and how it will be used, but working on the roof this week got me thinking that I would like to lay out in a blog our process of restoration as it involves roof systems and roof boards.

Old Barn Restoration: The Process

Our first step when we get the frame labeled, disassembled and home is to pull the many antique nails. And I mean many! When a frame comes to us, it has usually gone through several generations of roofing material. Often our barns were first roofed with cedar shingles. This roof will last for 30 to 40 years before it has to be replaced.

From Slate to Cedar Roofs

A barn built in the 1700s had at least two or three iterations of cedar before the next big event in New England roofing: the development of the slate industry. In between these generations of roofing materials, the nails were tapped down into the boards rather than being removed. That leaves it to us to get all that metal out. It is fascinating to see the generations of nails in a single board- from hand forged, to cut, to modern wire nails. We tap them from the inside first, careful not to mark the show surface with our hammerheads. Then we flip the board over and pull them out. We save the handmade nails, and throw the rest into our metal recycling bin. Removing nails to restore wooden beamsRemoving nails to restore wooden timbers

Washing the Timber Frame and Boards

Next, we wash the frame and the boards. It is amazing to watch two hundred years worth of grime fall away from the boards! It feels like painting in reverse – allowing the incredible patina to come through that only a century or two of light and air can create. It is a process that requires great care; if we wash with too little pressure, the patina does not come out, but if we use too much pressure or pause in mid-stroke, the water will raise the grain of the wood and cause an unsightly mark. IMG_3482

We can not put away the boards when they are wet because of the risk of mold. So we dry them in the sun like so much laundry on washing day. The end result of all this handling is worth it when we see the sun shining off these vintage boards. They will make a stunning ceiling when the barn is re-erected. Restored timbers drying in the sun

Reassembling the Rafter System

Next, we are ready to assemble the rafter system. We make any necessary repairs and replacements to the rafter system, and then we assemble one half of the roof at a time. In the next photo, you can see the five-sided ridge beam from a restoration we completed last summer. That particular roof had four braces that went from rafters to ridge beam.

5 sided ridge beam barn restoration

We check the peg holes to make sure that the new pegs will hold strong and true. If necessary, we re-drill a peg hole where a “new” rafter was installed or where we made a repair to a rafter tenon.

restored timber rafters | Green Mountain Timber Frames

Laying out the Timber Roof Boards

Now we lay out the roof boards. All the roof boards are labeled as we take the barn down, but we very often have to straighten some edges and switch out fatigued boards for others with similar color. Remember all those generations of roofing material? Very often there was a drip somewhere at the end of the lifespan of each layer of cedar, and thus very often we have to replace some of the boards.

There are blond “shadows” on the underside of the boards where contact with a rafter shielded them from light and air. We do our best to line these shadows back up on top of rafters. Complicating this process is the fact that half-round or hewn rafters are rarely straight, so the spacing of the shadows varies depending on the spot in the roof. Doing this work while flat on the ground at the shop allows us to be as careful as possible with color matching, board spacing, and shadow hiding. Luke Larson | Green Mountain Timber Frames

Restored roof boards

Checking the Roof Board Labels

As our final step in this part of the restoration process, we carefully go through the boards and check the labels. We have a system of marking the outside of the boards so that we can efficiently apply them when the rafter system is standing.

Timber Frame Label System

The end result is a timeless visual ceiling. Or, perhaps we should rather say time-full. Here is what it looks like on one of our completed frames that now stands as a barn home:

Restored Timber Frame Ceiling

Back to Roof Restoration!

Let’s get back to that roof restoration that we completed yesterday. Here are a few more photos from this week’s restoration of our little corn crib roof. With a footprint of 14×18, this barn is a miniature of some of the larger barns we work on, but it is not small or modest in craftsmanship.

The half-round rafters are beautifully tenoned into the five-sided ridge beam, and the rafter tails have an elegant “swoop” at the eve. When we put this frame back up on its new foundation, the roof system will be ready to support many future iterations of roofing materials.

Stay tuned to learn more about this restoration, and about the exciting future home for this frame.

Have questions about restored barns? Dream of living in a timber frame home?

Contact me!
Luke – 802.774.8972 | Luke@GreenMountainTimberFrames.com

Below – enjoy more pictures from the roofing project!

Tenons on the Pawlet Corn Crib rafters

Tenons on the Pawlet Corn Crib rafters

IMG_2620

Rafter tails with swoops on the Pawlet Corn Crib

Roofing Material: A Weighty Decision!

Reading this in your email? For easier reading – Click here.

I remember one time as a kid when a great-uncle told me about the historic New England turkey drives. As I listened open-mouthed, he told me that New England farmers of the 1800s used to join up in the fall to collectively bring all the turkeys they had raised down to Boston. It was before the days of the interstate and refrigerated trucks, and as he recounted, they would shepherd thousands of turkeys across the countryside over a number of days.

vermont-wild-turkeys

The turkeys would collectively roost on the ridges of country barns every night. “And that, my friend, is why so many Vermont barns have big sags in the ridge line – it was the weight of all those fat turkeys on their way to market!”

To this day I am not totally sure if he was pulling my leg completely about the “historic turkey drives,” but one thing is for sure: there are indeed many historic barns with saggy roofs. In our voyages around New England viewing barns, we very often find sway-backs. That is, buildings where the roof has sagged dramatically under the weight of slate.

The history of our slate industry

Green Mountain Timber Frames has its base of operation right on the edge of a slate valley and it is fascinating to think about the interplay of geography, geology and population movements as it relates to this industry. Slate first gained attention in our area around 1834. The first known barn to receive a slate roof in our area was in 1848. By the end of the 1800s, the slate industry in our valley was booming, bringing in groups of skilled quarry workers from Wales, Czechoslovakia, Poland and many other parts of the world where people had experience with slate.

Before this, our barns were roofed using hand-split cedar shakes.

handsplit-shingles-or-shakes_historic-roofing

Hand split shakes – image courtesy of http://www.nps.gov

Builders would cut cedar logs into 30 to 36 inch lengths and then split them into shingles using a tool called a froe. In some places where there were not readily available streams for early water powered sawmills, builders would forego roof boards completely. Instead, they would heavily brace the rafter system to make it ridged, and then would install strips of wood called purlins spaced up to 36 inches apart. They would then apply long hand-split cedar shakes directly to the purlins.

From cedar to slate

Cedar is a natural, light, and wonderful roofing. Like the planking on an old wooden boat, it would have large gaps when dry. As soon as the first rain drops soaked in however, the cedar would swell and shed the water beautifully!  However, cedar roofs last only a few decades. As the cedar started to fatigue on our earliest barns, farmers began to replace it with slate. What could be better than a local product that will last as roofing for 200 years? What farmer really has the time to replace cedar every few decades?

There was just one little problem…cedar shakes weigh about 400 pounds per 100 square feet. Slate, on the other hand, weighs as much as 1,000 pounds on that same roof surface! On a typical 30 x 40 barn, this means that the new roof weighed as much as 9 or 10 tons. For a barn designed for a lightweight roof, trouble came a-visiting, especially when the heavy Vermont snows also piled high on top of the slate.

before-and-after-barn-transformation

How does geography fit into this?

Here at GMTF, we have recently viewed a number of barns in northern Vermont. These structures were far from the slate quarries and were thus more likely to receive roof makeovers with multiple generations of cedar, followed by lightweight metal roofs (once that industry came into full swing.) We find that, unlike with slate, many more of these northern barns survived with roof-lines in tact.

How do we restore these barns?

There are several building techniques that we use to rehab a barn that was built for cedar rather than our modern heavier insulated roofs.

We find that the old barns with ridge beams faired much better over the past couple of centuries.

1790-barn-with-5-sided-ridge-beam

This 1790s frame received slate mid-life, yet look how straight the roofline remained because of the 5-sided ridge beam!

To further strengthen a ridge beam roof system, we sometimes add vertical posts going from heavy timbers to the ridge beam. This transfers the weight straight down and minimizes the outward thrusting forces that otherwise can push the eve walls out.

historic-timber-frame-barn_green-mountain-timber-frames

In this historic barn, there are posts going up to the ridge beam to further strengthen the structure.

 

As builders became aware of the weight issue, they often added a “queen system.” This is a structural system that picks up the weight of the rafters at mid-span and transfers this weight down to the heavy girt timbers and posts. On many of our oldest barns, we use vintage timbers to create this type of a system.

barn-featuring-queen-system-as-rafter-support_green-mountain-timber-frames

This  “queen system” helps to support the rafters.

queen-system-for-rafters-with-vertical-posts_green-mountain-timber-frames

Queen systems come in many shapes. This one uses vertical posts rather than angled.

Another method we use to beef up the rafter system is to add collar ties to the rafters. These horizontal timbers create a triangle within each pair of rafters, which is one of the strongest geometrical shapes in nature.

collar-ties-on-north-hero-vermont-barn

We installed these old-new collar ties to help stiffed the roof on this North Hero, VT frame.

How can we repair slate fatigue in place? 

On a recent project, we were asked to help prepare the structure of an 1860s house for a new roof. The builders had sized their rafters for a light roof and then installed slate. The sag was tremendous. We did not want to disturb the original plaster of the ceilings beneath the rafter system. Our solution, after the slate was removed, included first adding collar ties in the attic.

new-collar-ties-to-strengthen-rafter-system-in-old-vermont-barn

New collar ties stiffen these old, undersized rafters.

Next, we screwed 2 x 4 rippings over the top of the existing rafters and snapped straight chalk lines.

img_4006

We used a string with chalk on it to snap a straight line

Here is how it looked after we used this technique on all the rafters:

curved-shims-on-new-roof-system_green-mountain-timber-frames

Making all these curved shims made us consider going into the wooden boat building trade!

Next, we put new plywood over the whole roof and it was ready for roofing!

new-plywood-roofing-on-vermont-frame_green-mountain-timber-frames

Ready, set, and on goes a new roof!

Restored slate roof by Green Mountain Timber Frames

The finished project has a much flatter and straighter roof.

Conclusion

It is so interesting, as we travel around New England looking at barns, to imagine the various economic, geographical and sociological forces that all played a role in barn designs! We are grateful to have learned from the craftsman of the past who figured out how to properly build roof structures to withstand the various forces that material and weather throw at them.


Want to live in your very own historic barn?
Let us know!

802.774.8972 or Luke@GreenMountainTimberFrames.com

  • To learn more about the fascinating history of slate, check out the fantastic Slate Valley Museum in Granville, NY.

The Gazebo Gets a Cedar Roof

Last week, we finished putting the roof on the Timber Frame Gazebo. Despite the 95+ degree heat, to which we timber frame builders in Vermont are not accustomed, we sweated it through and completed the framing project in a few days. It really was fantastic heat for a couple of ole timers, so we started and ended early each day and headed to the pond or pool for an afternoon dip!

American Arts and Crafts Movement Red Cedar Roof Vermont TimberframeWe are satisfied with the results and I think even the Greene brothers would be pleased! In this picture, you can see how we laid the roof boards. Because cedar shakes need to breathe, we left 3/4 inch spaces between each of the boards.

Cedar Roof Slats on Timber Frame Vermont

                   Cedar Roof Slats

To complete the gazebo, a stone mason will be adding stone work around the edge of each masonry pillar anchoring the post and beam frame. In the photo below, you can see a mock-up to offer a sense of how the stone pillars will look when finished.

Timber Frame Vermont

         Mock Up of Stone Masonry

These turkeys seem to think it might be a fine place to roost!

Vermont Timberframe Turkeys

“We’ve found the perfect roost!”

While this isn’t a timber frame for sale, we have plenty of available frames in stock at Green Mountain Timber Frames. And we are always having fun with new and exciting projects – from reclaimed timber frames and custom barn homes to timber frame restoration and green barn homes here in Vermont and throughout New England.

We would love to hear from you – or show you around our shop during a visit to Middletown Springs, VT.