Once you figure out the math, the rest is just glue and sawdust.
“You want what?” You’re kidding!”
That’s what I thought when some very good clients asked me to build a railing for a second floor deck above a living space. I hesitated — I normally do interior finish work, not decks.
But when they said they were thinking of a Chinese Chippendale balustrade, they got my attention. In general terms I knew what Chinese Chippendale design was — I’d just never built anything with the geometric fretwork patterns that mark that style. It’s beautiful stuff.
Needless to say, as a finish carpenter I was very intrigued and very interested — I mean, how often do you get a request like that? I gave them a naïve “Yes,” not knowing the complexity of the planning that would be involved. In the end the time and effort were well worth the finished product. And the lessons I learned might help me actually make a profit next time I do a Chippy — if there is a next time.
What the heck is Chinese Chippendale anyway?
Fortunately through books and antique furniture, I had been exposed to the general notion of Chinese Chippendale design. Named after Thomas Chippendale (1718-1779), England’s most widely known furniture maker, the design motif comes from his interest in incorporating Chinese and other Asian designs into some of his furniture, which are now expensive antiques that are widely copied.
The repetitive geometric line patterns, usually within a rectangular framework, are varied and beautiful, but quite complex for a builder or artisan to execute. During the colonial period Americans adapted and used Chinese Chippendale designs for fence railings, porch balustrades, railings around widow walks on roof tops and also for interior staircases.
Chippendale elements were usually built for people of means, and they are evident in the preserved homes in colonial Williamsburg, and famously at Jefferson’s Monticello. That’s all well and good, but after building a version of these railings, I’m convinced that the design is retribution by the Chinese for the slavery and ill treatment that they suffered in building the American railroads — their form of righteous payback.
Choosing a design, and planning for the project
The owners started by giving me an enlarged photograph of their 1920’s brick colonial house taken in the 1940’s, when a railing existed on the deck. I could just make out the general pattern of posts and the railing design in the fuzzy picture (see photo, Right). The assignment was to create something close to the photograph, but with a more elaborate Chinese Chippendale balustrade pattern. We looked at fretwork patterns from books on historical homes and on line, and picked one that had a highly defined, repetitive diamond pattern (see photo, Left).
Planning for this seemly simple project was key, because the design, fabrication, fitting and installation all had to be considered both individually and in the scope of the entire project. The project was relatively small: a 25-ft. by 12-ft. three-sided railing. But there were many considerations. We’d chosen a Chippy design but we had to determine how it would work within the parameters of this railing and with the post placement. We also had to verify the building codes for railing height and for the space between balusters or in this case between the frets.
We also had to decide whether to custom make all the railing elements or incorporate stock items. Then there were the questions of what wood species to use, how to cut a billion pieces of wood accurately so that they could be assembled without error or mistakes, and what fastening system to use to put the railing together.
Up on the roof I had to figure out how to assemble the balustrade sections solidly, along with the not-insignificant matter of how the railing system would attach to the roof deck. Not only did the railing have to be solid, but the attachment method had to prevent leaks into the home library on the first floor below.
Beginning in the past
Because we were installing a railing on an existing deck or roof using an old photograph, we had to start at the end, with the roof itself. The roof was not really intended to be a deck. A door from a second floor room opened onto the roof, which was covered with an older EDPM membrane.
The original posts for the railing had been inset from the edge of the roof by about a foot on all three sides. We knew this because the roof soffit extended out a foot from the brick walls below, and the posts would have aligned with those walls. Plus there was a faint outline of white paint on the brick-wall side of the roof deck where the two end posts had stood. On the outside corners the old photo showed evidence of tri-posts, a corner post flanked by posts close by on both sides. There also appeared to be at least one center post on the long run.
With all this information in hand, I used the rough lengths of the sections, and positions of the posts to start the planning process of how to fit the Chippy design into the lengths that I needed. Oh yeah, I also had to figure how to fit those lengths into the Chinese Chippendale pattern that we’d chosen. The two aren’t the same and, in the end the Chippy design trumped the lengths because everything springs from the mathematics of the pattern.
The Zen of the diagonal
The Chinese Chippendale designs are all about math, but I found no books on how to do that math. Every measurement affects every other measurement, and once you have the correct measurements, everything falls into place and it’s constant. But I couldn’t find that magic measurement. After much painful thinking, I realized that all thinking is irrelevant; kind of like a fortune cookie or Zen and the art of Chinese Chippendale.
As I worked with the pattern it became clear that although everything in the Chippy design is interrelated, the key element is the diagonal. Once a diagonal is drawn, and the vertical height is established relative to that diagonal, then the length of the sections are determined for you. The diagonal and its opposing diagonal, zig zag in length within the height parameter creating a diamond configuration. As these diamonds form, the length is set automatically, along with multiples of the diamond.
Because this particular Chippy design is measured in multiples of diamonds flanked by half diamonds (diamonds cut vertically down the center) everything is resolved for you once you have the size of the diamond. With all things perfect — as they should be — then all the sections are equal in length. OMMM…
Plugging in the variables
Armed with the diagonal axiom, I could start laying out the particulars for the balustrade by working from some known points, the first of which was the building code. Massachusetts Residential Building code stated that the top of the railing had to be a minimum of 36 in. off the deck surface. Also there could be no more than 4 in. of space between the bottom rail and the deck surface. The code also stated that the open space between balusters should be no more than 4 in. (Because there are no vertical balusters in the Chinese Chippendale design, I interpreted the 4-in. rule to mean no more than 4 in. of space between any of the diagonal fretwork pieces.) Taking the code into account, I began my rough layout.
Even though we’d picked a chippy design, I still needed to work out some crucial details. The first item was the thickness of the frets — what would look best once the proportions of the Chippy sections were known. Together the clients and I decided that thick fretwork would look better than something thin and spindly. We wanted a thickness that came close to the 2-in. dimension of the brick façade. Because I was building this railing in wood, and knowing that I was going to be making the fretwork out of rough 8/4 boards, I set the width of the frets at approximately 1 5/8 in.
Stock parts wrap around the custom balustrade
Our next task was to work out the details for the top rail and bottom rails, along with the frame that typically encloses each Chippy section. Those dimensions subtracted from the overall height would give us the height of the diamond pattern.
As the design and layout evolved, the owners and I decided to use stock rails, subrail, bottom rails, post sleeves and post caps. I could buy and supply these parts less expensively than making them from scratch. We selected a railing pattern from Woodway, a company that makes cedar fence and railing systems.
We chose profiles that worked with the overall Chippy design and that mimicked details elsewhere on the house. Together we selected 6×6 post sleeves, their Estate profile handrail and bottom rail, a standard subrail and pyramid post cap. For final assembly I also used Woodway lag-eyes to fasten the bottom rails to the posts.
Lots of math and a half-size drawing
With all the measurements of the parts and the rough dimensions between the posts, I was ready to plot out the exact dimensions of the Chippy sections. I started with a finished height of 37 in. for the top of the handrail to ensure that no surprises during assembly or installation would effect the minimum 36-in. code height requirement. (Adding that extra wiggle room might have been the smartest thing I did and sure made the job easier! You’ll see what I mean in a minute.). From that number I subtracted the height of the handrail and subrail (2 1/4 in. measuring to the groove in the subrail! Fig. 1),
subtracted the height of the bottom rail (1 in. not including the lip! Fig. 2),
and subtracted 4 in. for the distance of the balustrade assembly above the deck. (When installing the railing sections, the 4-in. dimension meant that I could hold the section off the deck with a 4 in. block on edge). The total I needed to subtract was 7 1/4 in., leaving a balustrade height of 29 3/4 in. I rounded that number up to 30 in., just to make things easier, and to provide a little more wiggle room.
The clients and I had discussed options for the framing around the balustrade. One choice was to tuck the fretwork tails directly into the subrail on top and let them rest directly on the bottom rail. But we opted to picture-frame the fretwork on all sides first. The frame then tucked into the subrail 3/8 in. on top and the lower frame attached directly to the bottom rail. Because the bottom rail had a 3/8 in. lip, and I wanted the exposure on the frame to be equal on the inside of the deck, I added 3/8 in. to the width of the top and bottom frames, making them 2 in. high (Fig. 3).
That 2 in. meant I had to subtract another 4 in. from the 30-in. balustrade height. All these calculations were critical for determining the actual height of fretwork, which had to measure 26 in., not counting the picture frame around it. Because the frame had to fit inside the groove on the sub-rail, I made all the pieces 1 1/2-in. thick, including the fretwork.
Using an old-fashioned drawing board and T-square I made a half-scale working drawing of a full section of the chippy balustrade. From this drawing I determined the diagonal lengths as well as the lengths of all the other fretwork pieces (Fig. 4).
From the drawing I also figured the total lengths of the Chippy sections, i.e. one diamond plus two halves, and two diamonds plus two halves. These dimensions (52 in. and 80 5/8 in. respectively) gave me the working dimensions I needed to figure out and fill-in the spaces between the posts.
Laying out the roof posts and figuring the fillers
The length of the long side of the deck was 296 1/2 in. With 12-in. set-backs on both ends, the length from the outside of one corner post to the center of the run was 136 1/4 in. Because the Chippy fretwork is limited to specific sizes, and because the corner and long-run middle posts were in set positions, I established that the largest Chippy section that would fit was a two diamond, two half diamond section.
The length of the Chippy sections left spaces on either side, so we opted for filler sections made from vertical square-stock balusters. For the long run I needed fillers between the corner post and the front flanking posts, as well as on both ends of each Chippy section: four equally spaced filler sections for the Chippies and two for between the posts.
Choosing a durable wood
Because of the outdoor application, I considered three wood species for this project: Eastern white cedar (indigenous to the northeast), Western red cedar, and cypress (PVC was not an option). Each of these species has its characteristics and merits, and all share a common feature of moisture and rot resistance. A lot of people might have considered fir, but I’d seen too many instances of fir not holding up to harsh New England weather. My initial pick was Western red cedar, but faced with delays in delivery, I decided to go with cypress.
Cypress grows in the wet, swampy areas of southern and southeastern coastal regions of the U.S. It is dimensionally stable with close, straight grain. It has few knots and generally doesn’t check and crack. Cypress also has no sapwood, it doesn’t bleed, and it holds finishes well. Cypress produces a natural preservative in the wood called cypressine that makes it resistant to moisture rot, insects, fungus, etc.
Cypress has been used for centuries in this country, beginning in colonial times for clapboards and exterior trim on houses. I figure that if some of the original clapboards on George Washington’s grandfather’s house were still intact after 250 years, then it would be a pretty good choice for my Chippy railings. As it turned out, cypress was less expensive than Western red cedar for the rough stock 8/4 boards I used.
Choosing the proper assembly method and tools
I am a firm believer that if you stare at something long enough and if it doesn’t go away, sometimes you figure it out. With the Chippy baluster I did just that: I looked at my drawing for a long time and wondered, “How do I best assemble the sections, making sure everything is anchored well? Do I use nails, screws, biscuits…?”
I kept bumping up against the fact that part of the fretwork would go together easily, but then subsequent parts wouldn’t because there wasn’t room for a fastening tool (I only had about 4 in. of space between fretwork in many places).
I concluded that the best way to connect the fretwork was with a Festool Domino joiner. By mortising for the dominos, and using large-size dominos I could provide the strength and rigidity needed. The domino shape also aligns the pieces in the same plane and prevents the assembly from twisting. With the dominos I could connect and attach all the pieces to each other and not have to worry about tools fitting into tight places. Because of the application, I opted for Festool’s Sipo 10 x 50mm exterior dominos.
In the places where I needed screws, such as attaching the fretwork to the subrail, I used stainless steel square drives of various sizes and lengths. Stainless steel eliminates any possibility of bleeding and discoloration. And I joined all the pieces with Titebond III, an exterior-grade glue.
After more hours of staring and cogitating — and more beer — I realized that I really didn’t need to be precisely accurate on the lengths of the major diagonals, the Y-shaped frets and the half-diamond pieces on initial assembly. In fact making them slightly longer than needed (by 3/4 in. or so) meant that I could then trim the entire Chippy section to exact dimensions after it was assembled!
A million little pieces
To cut all the interior fretwork pieces exactly the same length, you have to use a repetitive cutting set-up with a flip stop and an accurately tuned miter saw. I had the good fortune of using a friend’s Omga miter saw and Accurate Technology Inc.’s ProScale digital stop set up. So after making a list of pieces that I needed (plus a few extras), I set the stop and cut away. Everything was dead nuts accurate. I cut all of the pieces on the exterior long, so I could trim them off later. Working with a 37 in. rail height allowed me plenty of wiggle room to make those trim cuts.
After I cut all the pieces, the next step was marking the half-lap joints where the major diagonal pieces intersected. Dry fitting was key to this step. Then I measured and marked locations for the dominos. Knowing these locations made it easy to cut template blocks and to transfer measurement marks to all the similar pieces for mortising. The beauty of the Chinese Chippendale pattern is that once you do have all the math figured out, all the measurements are the same — the lengths, the spacing between pieces, the angles, etc.
At this point I made the first mistake that I’m willing to admit. I cut all the mortises for the dominos for the first Chippy section for tight fit. That worked well for joints like the dangling Y’s. But it wasn’t good for the pieces in the center of the diamond, or for the 45° mitered ends of the major diagonals. With the tight fit it was impossible to assemble the Chippy. So after more staring and scratching, I decided that certain of the domino joints needed to be cut wider to allow for a little side-to-side movement during assembly. Fortunately, I caught this mistake during the dry fitting of the first Chippy.
Start spreadin’ the glue…
With all the pieces cut and mortised, it was time to glue and clamp — my hour of reckoning. I spread out all the pieces and dominos on a workbench along with clamps, glue, and I kept a cup of water to wipe excess glue at the ready.
The major challenge was assembling the double diamond portion at one time. I was literally gluing and clamping 23 joints: 3 lap joints, 4 miter joints, and 16 butt joints with dominos, and all within the set up time of the glue. Titebond III is gives a strong, weather-resistant bond, which is a good thing. But it has a shorter working time than ordinary wood glue, so I had to work fast.
As you might think the first section took longer than the others to do, but I managed to do them in about 15 minutes each. All of the “add-on” fretwork pieces like the Y’s were assembled and glued to the section after the full diamonds were done.
I clamped the mitered joints that joined the diagonals with Jim Chestnut’s Clam Clamps. Jim probably never anticipated his wonderful miter clamps would be used to assemble a Chinese Chippendale balustrade, but they were the balls for holding the diamonds in perfect position while the other pieces were joined with the bar clamps.
Keeping the dominos loose gave me the wiggle room to adjust and fine tune things as the fretwork went together. While the assembly was clamped in position, I shot two 1-in. 18 ga. pins into each side of the joint to hold the pieces in place while the glue dried completely (see photo, Left). The domino joints with the Titebond III glue were extremely strong. I literally picked up an entire Chippy section by the two Y’s and extended it horizontally with the full weight supported easily by just the two domino joints.
The final step was cutting the fretwork sections to perfect height and length. This is where that extra wiggle room really came in handly. Even with all my careful calculations, the railing wasn’t nearly the finished size I needed — talk about cumulative error! With all those pieces…well, never mind. You can probably imagine. Now I had the chance to trim the height so the railing would be almost exactly 36 in. from the deck.
With the Festool TS45 plunge saw and guide rails, I nipped about 3/8 in. off the diamond points, which — coincidentally — also provided a perfectly flat surface for attaching the outer frames! Cutting with the saw rail on the marks trimmed the Y’s as well. For the length I set a short Festool guide rail on the center of the half diamonds and cut the extra ends that had been left long.
All filler baluster pieces were cut to length and taken to the job site loose. Fretwork picture-frame pieces were left long and all the stock parts were left in factory lengths to be cut and fit at the job site.
All the pin holes were filled with exterior wood filler and sanded. And I did a final sanding to even out any joints not perfectly flush, although the domino tool left the joints nearly perfect. Any joints that were not flush were probably from me tipping the machine while plunging the mortise. (Wait; did I just admit another mistake?)
We decided to pre-finish the Chippy sections, along with the rest of the parts and pieces before delivery to the worksite. Fortunately I had access to a spray booth. I couldn’t imagine a painter, the owners, or even worse, myself, finishing everything after it was installed. Finishing beforehand worked out well; only a small amount of touch up was required.
All pieces received two coats of Cabot’s white primer and two coats Cabot’s exterior latex PRO VT Solid Color Stain. Although a coating this complete was probably not necessary for the cypress, it was necessary to help prevent bleed through of the Western red cedar tannins in the railing and post stock. With the spray-booth finish, the Chippy parts were perfectly covered and coated. We were building furniture after all, right?
Working with the roofer to place and anchor posts
Part of the work on this job was adding posts to the deck. As mentioned previously, we were able to see where a railing and posts had been in a previous era (see photo, Left). But because the roof was being covered with a new EPDM membrane, I made sure the roofer worked under my supervision so that I could properly prepare for the structural posts I opted to use.
Because the placement of the posts had to be within a fraction of an inch for proper fitting of the railing, I chose to use structural steel posts to simplify installation (Call me a prima donna, but I didn’t want to rip the old roof sheathing apart and kneel with my head in a hole trying to lag twisted pressure-treated or cedar posts to the porch rafters.).
The 4×4 structural posts I chose came from Fairway Vinyl Systems. Each post consists of a galvanized steel pipe welded to a square bottom flange plate. The plates had pre-drilled anchor holes through which the post is lagged to the surface. Two adjustable square, plastic sleeves on the top and bottom of each post, accept the 6×6 post sleeves and serve as shim points as well as nailing or screwing surfaces for the railing connections.
For this application, I found the structural posts allowed me to be more precise with placement, and they were very forgiving considering the existing conditions. The posts cost more than their pressure-treated counterparts, but not much more than cedar posts, and they were much easier to install.
Installing the balustrade
Next I used a Hilti PD40 laser distance measurer to make sure the two sections on the long roof run were equal. I measured each section at the top rail and bottom rail positions. The subrail and the top and bottom picture frame pieces were cut to this length.
Two of the vertical filler pieces were screwed to either side of the Chippy fretwork (the half diamond ends) to start the picture frame. The total length of the Chippy section was subtracted from the distance between the posts and divided by two for the dimensions of the filler pieces that I had to make up for each side of the fretwork sections. We put the fretwork and horizontal frame pieces on the roof top work bench.
|After centering the fretwork on the top and bottom frames,|
|we screwed the picture frames to the fretwork.|
We still had to install vertical balusters to fill the areas on either side of each section. The distance between balusters was calculated the same way I calculate balusters for a railing or stairway. For the Chinese Chippendale balustrade the picture frame pieces on either side of the fretwork act as balusters in the fill area. With the spacing established we screwed the filler balusters into the assembly in proper position.
Working from underneath we screwed the subrail into the top rail with short screws. That assembly was then screwed to the picture frame of the Chinese Chippendale section, again by driving screws from underneath the top picture frame. The bottom rail was screwed from below into the bottom of the bottom picture frame.
This last step was a little tricky because we had to make sure that the bottom rail profile was oriented correctly with the lip facing inward, and that the section was assembled and ready to be installed with all the Y’s facing the same direction. The Chippy railing section was finally assembled and ready to install in one piece.
|On the bottom we drove screws through the eyes in the lags to secure the bottom rail.|
Final touches included wrapping the bottom of the post sleeves with small base shoe, and installing the post caps. We also fit crush blocks under the railing below the diamonds in each section, one or two depending on the length of the section.
The last remaining chore was building and installing the filler sections between the corner posts and the flanking posts. We built these sections with vertical balusters to match the Chippy fillers. Assembly and installation was the same for these sections as well.
Crafting this Chinese Chippendale balustrade was an extremely satisfying, albeit challenging, project. But most of us carpenters like a challenge. The amount of time spent planning (plus staring and thinking) was disproportionately high compared to most jobs I do. The actual cutting, assembly and installation were the easy parts. But as with all work, careful planning makes short work.
The end result was a piece of art — almost like a piece of furniture. If you have occasion to build something similar, be patient. Drink beer — after work! (I recommend Wachusett Brewery’s Rye beer). And if you have friends like mine, be prepared to hear “Better you than me!” every day you’re working on the project.
. . .
Please don’t try anything you see in THISisCarpentry, or anywhere else for that matter, unless you’re completely certain that you can do it safely.
. . .
A small-town “middle-aged boy” from Minnesota, RJ Davisson started building and carpentry when he was just 4 or 5 years old. Back then he swung a full-size hammer, but had to choke up a little, and he wore white work boots — what’s up with that! He learned his strong work ethic from his parents, independence and self-reliance from his farmer-grandfather, and carpentry from his uncle, “Donk,” who was a master carpenter, cabinetmaker, finish carpenter of the old school. When barely 8 years old, RJ was in the woods with his uncle cutting trees, hauling them out, and transporting them to a local lumber mill where the logs were milled into planks. At the shop, the lumber was stacked and stickered, and a year later they’d be making custom kitchen cabinets — they were all custom in those days — planing the rough stock, jointing, cutting, shaping and assembling. By age 15, RJ had built three houses — from foundation hole and home-made concrete forms, to hand-cut rafters, hand-nailed strap- ping and toenailed studs — No nail guns, no… Well, you get the idea. It was particularly satisfying where one house had custom-milled paneling of different species in each room: cherry, black walnut, maple, butternut, ash, oak. Thank God they invented nail guns and SkilSaws.
RJ’s love of wood has helped him make a career doing what he likes — making beautiful things that draw on the wisdom of the past and that stand the test of time. He built his own house styled after a 1700s simple Deerfield house, complete with forged thumb latches, tin sconces, face-nailed wide pine floors, a “good morning” staircase, and — at the insistence of his wife — running water. RJ has built furniture, influenced and awed by the beauty, simplicity, and craftsmanship of the Shakers.
A love of sailing introduced RJ to wooden boats — he just doesn’t get the whole “plastic” boat thing — and he has restored several. A purist in most things — black (unflavored) coffee, beer, martinis without all the frou-frou — RJ’s boats were pure sailboats: No lights, no radar, and no motor… Beetle Cats and Wianno Seniors for those that know and care.
Married for 33 years — yes, to the same woman! — RJ has been told that he is alternately either 66 or 16; too damn serious or acting like an idiot with no in-between. Two daughters and three dogs later he is relatively sane. An only child himself, having such a “large” family was an adjustment, but one that he loves and wouldn’t have traded for the world. Now and again, though, a cabin in the remote wilds of Montana sounds good.
Generally finish carpenters are a bit obsessive-compulsive, but RJ wonders what that is all about. Isn’t it normal to have 83 (and counting) cookbooks? When he isn’t working with wood, RJ loves to cook — plain, simple, exotic and complicated, BBQ or gourmet — he has tried cooking just about every cuisine from every country. And then there’s his OCD thing with dogs — all pointers — a German Short-hair, a Hungarian Viszla, and an English.
RJ plays the piano not-so-well anymore. And back in high school he could actually play the bassoon, affectionately known as the “farting bedpost.” He won archery trophies growing up in Minnesota. The Army had him in his grasp for awhile and tried to recruit him as a Ranger. But he just wanted to go home.
RJ fixes cars and his tractor. He still feels guilty that he has not learned SketchUp. And he is very sick of plowing the snow from his 500-foot driveway this winter.
RJ is a licensed general contractor, and his company, Davisson + Associates in Sterling, MA, specializes in finish carpentry, remodeling, restoration, and renovation.