Roofing

Nothing But the Roof

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A Yestermorrow semester program built an apartment property for Jas. In a win-win arrangement, Yestermorrow students gained real-life skills in design and carpentry, while Jas got free labor. Unfortunately, the class ended this week and the students left the house incomplete. Jas hopes to at least get a cover on the roof before winter sets in.

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The 400-square-foot apartment one week before end of semester.

So I found a free afternoon to get started. As soon as the Yestermorrow class finished installing roof rafters, I joined Allen to begin sheathing the north side. The tasks were familiar: start in a bottom corner, use tongue-and-groove Advantech with the tongue pointed downhill, install sheets so they break in the middle of a rafter. We snapped a chalk line across the rafters to align the top edge of the first 48-inch-wide sheet, wanting a bottom overhang of 1.5 inches. Then we cut the first sheet of Advantech with a circular saw to trim the length for a ¾-inch outside overhang. Once the first one is in place, the rest follow smoothly.

Several characteristics of this project were unique. The rafters are 16 inches on center, which leaves too narrow a space to pass a 96-inch-long sheet out without endangering someone’s safety. Therefore we raised the Advantech from below, with Allen and I sliding each sheet up a pair of ladders before ascending ourselves. The other concern was the location of the rafters in space – alignment is always a concern when you inherit a project from somebody else. The sheathing must stay in one plane so the finished roof doesn’t look wavy, and it should bear on every rafter for structural reasons. I used a long skinny half-inch-thick piece of Advantech to shim out one rafter that sat a half-inch low, sliding and squeezing it between the lumber and the sheathing.

Allen and I lift the sheathing…
…and align it on the rafters.

Jas and Allen soon completed the north side of the roof with Advantech, and then I helped sheath the south side using salvaged T-1-11 siding from the shed removal. It’s a race against the clock to get the sheathing installed and covered with Ice & Water Shield before the weather gets too cold and snowy to work safely. (People do it, but I’m no fan of outdoor construction in the winter.)

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Jas installs a safety harness system to finish the south side with T-1-11 sheathing.

China Week: Architecture

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I just returned from Beijing. Over the next seven days, I will write seven articles about my experience. Enjoy!

The “business” portion of my trip to the Chinese capital lasted four days, leaving me a week to sightsee. I quickly became enamored with the lavish palace architecture, and I appreciated how the style is echoed citywide in even modest buildings. Bearing the standard for this architecture, at the geographic and cultural heart of Beijing, is the Forbidden City. It served as the Emperor’s home and court during the Ming and Qing Dynasties right up to the Boxer Rebellion at the turn of the 20th century.

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The Gate of Supreme Harmony, near the south entrance to the Forbidden City.

When you look upon any hall or pavilion in the Forbidden City, the first thing that strikes you is the roof. It imposes with two or three tiers stacked like a wedding cake. Each tier flares out at the eaves, where regular columns provide support and create a perimeter arcade. The roof rafters are smallish, square or round in cross section, and spaced closely in several layers. Many rafters are needed because the curved clay tiles which overlap to form the roof are quite heavy.

Halls are usually rectangular, pavilions six- or eight-sided, with a procession of beastlike bronze sculptures adorning the hips. The number of beasts in the procession is a code for the building’s importance. The Hall of Supreme Harmony, where the Emperor held wedding ceremonies and coronations, tops the list for the whole kingdom with eleven beasts.

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Five beasts = a building of moderate importance.

All exposed surfaces are painted with a palette of red, blue, green, and gold. Walking around the Forbidden City and temples from that era, I saw the 600-year-old buildings in various stages of restoration. Header beams are decorated repetitively with geometric patterns, intertwined dragons, and floral schemes. In contrast, the Summer Palace just north of the city was largely built in the 18th century. While the roofs there look the same, the paintings are much more intricate – thousands of unique frescos depict mountain landscapes and daily life.

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Paint detail in the Forbidden City.

Common architecture in Beijing imitates many elements of the palaces and temples. Loadbearing walls in the city’s hutong (alleys) are a simple double course of brick. Grey brick faces the street and red brick faces the interior courtyard, with an open space in between for insulation and airflow. Heavy timber beams support familiar square rafters, but they’re unadorned. Roofing tends to be a less colorful, less flared version of the same clay tile, though corrugated metal is common as well. Mortar is mixed by trowel in a pile on the ground. The city seems to dictate a schedule for restoration, and it’s not uncommon to find an entire block under construction. I wanted to wander endlessly, marveling at the juxtaposition of history and modern life in these neighborhoods.

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Typical hutong – tight space for a car. Walls are plain; roofs are ornate.

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Courtyard home under construction.

PERCH began two years ago with a focus on local business, and China is about as far as I can get from “local”. But when opportunity knocks, one must open the door. Check in tomorrow to learn about doing business in a foreign land.

Habitatting

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Habitat for Humanity is building a house in East Montpelier. Last fall I tried to contribute to this project as an engineer, but a team of Norwich University students designed the house and I wasn’t needed. Now that it’s under construction, I can lend a hand in a much more literal way.

It’s been more than a year since I last worked on rough framing, and it felt great to lug materials and climb around like a monkey. Even better, I got to test my competency. Head carpenter Chris put me in charge of a roofing crew: a team of five from the Montpelier USDA office who took an outing to join us. Also on site were longtime volunteer Lisa and project manager Bruce.

Polly and Lisa cut Advantech sheathing.
Ted, Mike, Ben, and I lift sheathing to the roof.

Our primary task for the day was to install as much tongue-and-groove sheathing as possible atop the scissor trusses that support three quarters of the roof. Chris and Bruce snapped a chalk line on the south side of the gable to get us started. For our first row we aligned each tongue (pointing uphill) with the chalk line. Subsequent rows we pounded into place with a sledgehammer and beater board. While Chris, Bruce, and Lisa puzzled out the geometry of the remaining rafters, the task of the roofing crew was relatively simple.

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Chris and Ben install a rafter in the southeast quadrant of the roof.

But no carpentry task is without pitfalls, and we encountered plenty. The scissor trusses are pretty squirrely on their own, free to sway until the sheathing provides shear strength. So we had to take care when we walked on them, and as we nailed down the sheathing we had to continually straighten the trusses so they’d line up perfectly. Usually we accomplished this task by marking the sheathing two feet on center, measuring periodically from the previous seam. Getting those seams right took some sledgehammer magic, too. When we hit one end in, the other end liked to seesaw out, unless we hit in just the right place or tack-nailed a corner to keep it from sliding.

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Snapping a chalk line to align the remaining sheathing panels.

The USDA team was a delight to work with. Ben actually built many houses while he was in school, and I appreciated his problem-solving intuition and acrobatics. Polly, Megan, Mike, and Ted learned fast, and what they lacked in experience they more than made up for in enthusiasm. Fears were overcome as everyone got up on the roof; the adage “many hands make light work” rang true. By day’s end we had over 90% of the roof sheathed – major progress toward getting the interior dry for the electricians who arrive next week.

(Did you know? The USDA provides rural housing mortgages and renovation loans with super low interest rates! Apply here and see if your income qualifies you.)

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Mike and Megan nail the last panel of the day into place.