Arch House: A Different Way to Build

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Without the generous help of family and friends, this owner-builder project would not have been possible.

People who have survived the building of their own homes often compare the experience to bearing and raising a child. There is the conception: A dream takes seed, planning begins. Next comes gestation: visible growth, a leap off the paper and into the soil. At birth, perhaps analogous to being “dried in,” the house takes on a life of its own, autonomous but far from complete. Later, often much later for the owner-builder, there’s the finished product–nurtured to capable, comfortable maturity.

But why such an odd-looking child–a house that looks like a mailbox, a loaf of bread, a pioneer wagon?

The notion for a barrel-vault structure (the accepted architectural handle for the “arch house” shape) came not from hoops and loops or my previous work with geodesic domes but from a rather unlikely source: Back in 1981, I noticed a classified ad offering (for an unheard-of low price) thousands of old 2 × 12s salvaged from dismantled bleachers. The catch was that they were only 6′ long–too short for conventional roofs, floors or walls. At first I toyed with the possibility of laminating the short boards into straight beams. But if I was going to the trouble to laminate, why not make curved beams?

I didn’t end up buying the old bleachers, but I did acquire a curiosity about arched structures built of segmented materials. During the six years of planning that followed, it became clear that plywood held many advantages over dimensional lumber. It was easier to handle, cut and fasten; it was extremely uniform and predictable; and it was readily available. With that settled, I knew how I wanted to build the trusses, and I knew intuitively such trusses would be wondrously strong. But I also knew that building inspectors and banks gave little credence to intuition. Doodling and research continued.

Then came a pivotal phone call. An old high-school chum called to tell me that a close mutual friend, age 32, had died unexpectedly. Deeply shaken, my wife, Nanny, and I sat down that very evening and decided it was time to do the things we really wanted to do–now. One of those things was building our dream home.

Draining our savings account, we were able to swing the down payment on a two-acre wooded parcel on a dead-end road in Lake Elmo, Minnesota, just east of the Twin Cities. A real bonus was the developer’s offer of a discount if we’d take the property with the dilapidated 90-year-old farmhouse that had stood vacant for years. To him it was a liability–an eyesore to be torn down and hauled away to make the lot salable. To us it was an asset–a place to camp while we built our home.

Planning the Arch House

We spent March of 1985 administering CPR to the old farmhouse. Electrical service was restored, and a new pressure tank brought the well back to life. Major quirks, like the kitchen floor that listed several inches and a toilet that imitated a bidet when the washing machine hit the rinse cycle, were simply endured. Frozen pipes in the winter, a leaky roof in the spring, walls sprouting mushrooms in the summer were the calendar pages by which we judged the seasons.

Longtime friend and architect Sheldon Wolfe agreed to wade through the structural and design elements of our new home. Drawing together information on plywood strength, nailing schedules, adhesive properties, live loads, dead loads, snow loads, wind loads and arches in general, Sheldon and his trusty computer painstakingly engineered the trusses.

Nanny and I designed the living space itself, taking into account the site, our lifestyle, our budget, materials availability and time limitations. Unlike previous houses, we wanted this one to accommodate us rather than vice versa. We both work, and with three active children, cleaning is not a priority; so we wanted storage space and closets throughout to streamline this task. Likewise, we wanted the laundry room on the same level as the bedrooms to avoid unnecessary trips up and down the stairs. Nanny was a smoker (until a few months ago), so we planned a small office complete with exhaust fan. Our children, Tessa Lou (four), Zachary (seven) and Maggie (ten), love reading and art projects. They requested both a quiet reading nook and an activity area. We also needed a convenient space for storing recyclable newspapers, cans and bottles. Finally, with Sheldon’s help, in the winter of 1987 we transformed our needs and wants and graph-paper doodles into a six-page blueprint.

After much scouting around, we found a local bank willing to finance the project. Included was an option that would allow us up to three years to finish and to search for a permanent mortgage–a cushion we sought as we had no firm idea how long our venture might take.

Thus armed with a $70,000 construction loan, a building permit, blueprints and unbounded enthusiasm, we began.

Beginning Construction

We broke ground in August 1987, with the hope of getting the house weathertight before the arrival of the chilling Minnesota winter. That would allow me, as a carpenter, to spend more time on the project through the slower winter months. Like clockwork, the day we began excavating, Nanny landed in the hospital with a mystery ailment–surely Mother Nature’s way of preparing us for the trials and tribulations ahead.

After excavation, the next major project was to construct the flat-roofed garage, which would sub as a workshop. We would cut the truss components inside, and on top we’d put them together (see sidebar).

While truss building lumbered (or should I say, plywooded?) on, we completed the remaining sections of the permanent wood foundation, the first-floor exterior walls and the second-floor cap upon which some of the arches would rest.

The arch is a nearly indestructible form, providing the legs (more technically, imposts ) are solidly fixed. The cathedral builders of old used massive flying buttresses to resist outward forces. We too used flying buttresses, but disguised in the form of the garage on one side and the small arched extension on the other. In addition, we put triple 2 × 12 top plates on certain walls, effectively making a horizontal header, and installed crossties in the open, vaulted areas to resist the outward thrust. In other areas, the plywood floor served as a gigantic anchor.

The moment of truth arrived one brisk fall day. All 31 of the 500-pound trusses lay staged and ready to make the move from horizontal to vertical. We had even rough-framed the gable-end window pattern to avoid unnecessary high-wire carpentry. Up to that point, all the work had been done by brawn, but when it came to raising those 32′-wide, 19′-tall behemoths, reason prompted a call to the local crane company. Every 2′ we stood a truss, braced it at the top and secured both legs with angle brackets. Eight hours and a few close calls later, the results of seven years of planning stood for all the world (or at least a few curious neighbors) to see. The house was at its purest that day. Perfect symmetry, one truss after another reaching for the sky, then returning to earth–a space-age skeleton waiting for skin.

The 1/2″ CDX plywood sheathing easily conformed to the gentle curve of the 32′-wide arches. Starting at the bottom and working up, we glued and 16d-nailed each sheet. At the horizontal joints between sheets, we drywall-screwed scrap plywood blocks between trusses to prevent bulges. Continuous soffit vents at the overhanging base of the trusses, and a site-built continuous vent at the “ridge,” assure a cold roof and a path for moisture to escape the insulation cavity. To work on the variably sloped roof, we used scaffolding consisting of a medley of ladders, siding brackets and roof jacks, along with safety ropes and vigilance.

Next we set and sheathed the 12′-diameter arches over the sunroom, and the 16′-diameter trusses with integral 4′ knee walls over the entry-office. It was pushing the outer limits of 1/2″ plywood to conform to the 16′-trusses, so we used two layers of 3/4″ plywood to sheathe the smaller arches. In each of three bedrooms we had to cut a truss and build a structural dormer-window seat to allow room for the required egress window.

Shingling provided its challenges. Junctures where curve intersected curve were particularly time-consuming. But a leaky shelter is no shelter at all, and the extra time was well spent. We used Dri-Deck (a sticky substance in roll form that adheres to the plywood and seals around nail holes) under the shingles near the less steeply pitched top and in other crucial areas.

The project was not without its chills and thrills. One day I thought I heard a loud conversation coming from the roof. When I realized that carpenter-friend Pete Boyd was working alone and had no one to converse with, I investigated. I found him clinging to a dormer with his “convertible” ladder lying converted on the ground below. Another time, a roof bracket collapsed as I was installing a metal chimney, and I took a toboggan ride (sans toboggan) down the curved roof. My first reaction upon landing wasn’t to check for bloody gashes or broken bones but rather to surreptitiously glance about to see if anyone had witnessed this embarrassing Keystone Kops maneuver. There’s nothing like a good close call to get you on your toes. 

Building a home, when viewed as a whole, appears an overwhelming endeavor. But when this “whole” is taken as a series of smaller tasks, the objective seems more easily attained. For us, getting closed in–shingling done, windows and doors installed, no longer at the mercy of the elements–was one such intermediate goal. Like tired parents with a newborn, upon reaching this milestone we paused with a feeling of satisfaction–for all of about 15 minutes–before embarking on the next leg of the journey.

From Frame to Home: Concrete, Drywall and Glass

When I heard that Peter Hasselquist (a longtime friend and an excellent concrete finisher, living in Kansas) was coming north with his family for Thanksgiving, I knew that would be the time to pour the 1,800-square-foot floor. Working with Peter and many other good friends, we wound up with a slab flat enough to be deemed “roller-skatable” by my oldest child.

Interior framing reinforced my belief that building one’s own home is at once a curse and a blessing. The free-spanning arches required no intermediate support walls, so the interior space contained limitless possibilities. So did our imaginations. Right away we began straying from the blueprint–adding a foot here, moving a room there–but we finally nailed down a livable floor plan.

We insulated the 2 × 8 exterior walls with 8″ fiberglass batts, and the trusses with two staggered layers of 6 1/4″ × 23″ batts. Wing-shaped foam spacers maintain a 2″ air space between insulation and roof sheathing. We installed and sealed the 6-mil polyethylene air/vapor barrier only after all the mechanicals were complete.

The plumbing I left to the pros, and after admiring their Rube Goldberg sculptures, knew this had been the right decision. After a moonlighting tinner installed the main furnace plenums and got me headed in the right direction, I finished the ductwork and chimneys. Electrical was roughed in with guidance from a selection of how-to books and the advice and help offered by another friend-tradesman.

Living 30 feet from the construction site was terrific. If I wanted to snatch an hour or two of work, the commute and setup time were not a consideration. By the same token, the house was always there, beckoning–a stern stepmother with an endless list of chores. I divided my days between working on “paying” projects and working on our home. Sixteen-hour days became my norm; many were longer. We jokingly began calling the house Christine (after the anthropomorphic car in Stephen King’s novel), as it took on a life of its own and began consuming all our time, energy and money. In retrospect, it may well have been Nanny who tackled the most difficult part of the project, for while I was mostly battling inanimate building materials, she was single-parenting three children while working a full-time job to boot.

A local company supplied the double-pane glass for the large fan-shaped window pattern. Rather than using curved glass set in steam-bent frames, we opted for less expensive, straight-edged glass and attained the circular look by band-sawing the stops from solid cedar.

“Getting ready for drywall” is another of those rungs one reaches for on the ladder of home building. The vaulted ceiling portion of the great room is finished in tongue-and-groove native Minnesota ash. Yet we still hung over 300 sheets of the heavy white stuff: By using a sponge to wet the back side of the drywall and then leaning into it, we were able to make the sheets conform to the curved trusses. With some tutoring from two professional tapers, I had planned to attempt the lion’s share of the taping myself. But when I compared how fluidly and swiftly they worked to how choppily and glacially I moved, I left the job to them and moved on to where my time was better spent.

We threw a painting party and, with the help of a dozen friends, coated the interior over one long weekend. Outside, all of the siding got back-priming and was treated with three coats of Sikkens wood finish before installation.

Trim work is the carpenter’s signature at the end of a long letter. It’s the reward for all the heavy lifting and careful planning that has gone before. Three other carpenters and I began this phase in the spring of 1988. The interior is, to say the least, eclectic. Sixty-year-old raised-panel oak doors with crown moldings salvaged five years previously grace the second floor. A mix of oak, ash and fir millwork is scattered about. More architectural antiques–leaded glass windows, maple railings, French doors from an old church, and stained glass–stand, reborn, throughout the interior. Friend and carpenter John Gruber spent two weeks meticulously finishing the double-deck stairway and railings in cedar.

I completed the tile work and cabinetry in late spring. We had known from the start we had neither funds nor time to finish the entire house before moving in. The family room, master-bedroom loft and office were unfinished. Ninety percent of our light fixtures remained as 49¢ porcelain sockets. Our lawn consisted of clay and rocks. But our attitude throughout the project has been, That which gets done gets done right; the rest will get done in time–also right.

Carpet was laid in early June, and we moved (or should I say, walked) our possessions over shortly thereafter.

It took less than three hours for a dozer to knock down the old farmhouse. Ninety years of mildew, dreams and lost sewing needles were neatly compacted into six dumpsters and hauled away.

Recently, at a party, I ran into the old high-school chum whose message about the untimely death of our mutual friend had gotten Nanny and me moving on our dream. He pulled me aside and, in an apologetic voice, explained it was a different person of the same name and age who’d passed away. Our friend was very much alive and well. I laughed until I cried. But better to do the right thing for the wrong reason than do nothing at all. Building our own home–like being parents–hasn’t been without trials, but our efforts have produced a home in which we hope to spend the rest of our lives. And along the way we’ve learned not only how far plywood and drywall can curve before snapping, but also how far the human spirit can bend before breaking. This last element is surely the most resilient of all–and will surely form the true cornerstone of any owner-built home.

Building Arc Trusses

Because today’s construction materials and methods are based on angles, building something curved requires a bit of improvising. We began designing the trusses from a set of “givens.” We knew we wanted to span 32′ to accommodate the desired room layout. We knew we wanted the trusses spaced every 2′ so we could use conventional building materials. We also had calculated that by nesting three 14″-wide arc segments, we could make optimal use of each sheet of plywood, thus minimizing waste. The unknown elements of the equation were these: How many layers of plywood were required; what thickness should this plywood be; what species and grade should this plywood be; and, finally, how should everything be fastened together? After thorough research, architect Sheldon Wolfe determined that we should use three layers of 3/4″ Douglas fir plywood. Construction adhesive coupled with pneumatically driven staples and nails would serve as fasteners.

At first, a router seemed the logical tool for cutting the curved components, but the expensive 3/4″ bits wore out quickly and left a pile of sawdust in their wake. A friend recommended that I try a standard 7 1/4″ circular saw. Lo and behold, it effortlessly cut the gradual 16′ radius. There were 31 trusses to build for the main structure, each consisting of 24 smaller arcs (“miniarcs” for clarity). With 744 individual miniarcs, each needing to be quite uniform, I knew constructing accurate jigs would be time well spent.

Since each truss has a built-in 3′ knee wall (to provide adequate headroom at the third floor), and since the laminations required staggered seams for strength, we needed five different shapes: full arches, straight vertical legs and combinations of those two elements. To make the jigs, we first swung arcs the exact size of the miniarcs on 1/2″ plywood. Then we carefully jigsawed them to shape. At the center of these patterns, we fastened guides for the edges of the bases of the circular saws to slide against. To accommodate the curve, I belt-sanded the tables of two Makita circular saws to the right radius–one convex and one concave. So the saw table rested on the full-sized, 1/2″ plywood template and was guided by the smaller inner ridge.

To cut a miniarc we temporarily drywall-screwed the template to a single sheet of plywood, cut the outer radius with the concave-modified saw, and then switched to the convex-modified saw to cut the inside radius. After removing this template, we clamped on another template to make the properly angled end cuts.

I estimated about 70% waste from each sheet, mostly in the shape of gigantic fingernail clippings. Eventually, we cut the scrap into 2″ × 6″ blocks and used them as homemade H clips to prevent bulging roof sheathing joints and as spacers between pieces of siding during back-priming and coating.

The trusses themselves were assembled on a simple pattern laid out on the garage roof. The first layer of miniarcs was laid down. Then the second layer, with staggered seams, was glued and fastened to the first with 1 1/4″ roofing staples. The third layer, again laid out with staggered seams, followed a similar procedure, but 2″ ring-shank nails were used to clinch the three layers together. We dragged the completed trusses over to the house and staged them in piles of five to await erection. Once all the miniarcs were cut, a crew of three–in rhythm to B.B. King tapes–could build a truss per hour.

Assembling the two smaller sets of trusses followed a similar procedure, but their tighter radii mandated the use of the router and an entirely different set of jigs.

All the trusses together consumed 280 sheets of 3/4″ plywood, 160 quarts of construction adhesive, 25,000 pneumatic fasteners and the time of myself and two other carpenters for a full four weeks. After a few days of cutting and assembling components, the novelty and excitement of truss construction settled into a repetitious labor of love.

My undying gratitude goes out to Tim Ofstead and Pete Boyd for their relentless attack on that mountain of plywood.

Editor’s Note: Owner-builder Gregg Carlsen is working with MOTHER on a set of arch house plans, available under the name “Archome.”