The right detail for the right price

Robert Steuteville

How to get authentic-looking traditional details is one problem that new urbanists have been trying to solve, with mixed success, for two decades. Building affordable housing is another. These two goals are sometimes in conflict, but they needn’t be, according to Donald Powers of Donald Powers Architects in Providence, Rhode Island.
The problem is the sizable gap between getting traditional details right and what production builders are prepared to deliver. From the middle of the 20th Century onward, affordable housing has been strongly associated with production building — which in turn has been associated with sloppy pseudo-traditional design.
“To me, the whole issue is intellectually stimulating,” Powers says. “How do you infuse the production world with a level of design that it has not had until recently, with the new urbanists?”
There are strategies, he says, and one is “to raise the level of craft on the part of the builders and subcontractors. Another is to lower the level of craft that is required. I don’t think that the two are in opposition. You can approach it at both ends.” New urbanists have done better at the first strategy than the second, Powers notes. “We have excelled at identifying the great details to the extent that we are scaring a lot of production builders,” he says.
Powers’s firm provides 3-dimensional construction drawings “that tell the builder what we want, in a way that is intuitive,” he explains. “At the same time we are trying to simplify the details as much as we can. I don’t think that’s a new impulse at all. It is consistent with the historical approach. It was as true in 1900 as it is today.” Like most new urbanists, he spends a good deal of time walking old neighborhoods with an eye for detail, “and I find very little that is perfect. Much of it is about 80 percent there to get the approximation of the correct detail.”
The skillful approximation leads to what Powers and other new urbanists, like John Anderson of New Urban Builders, call “the street version of the correct detail — the one that works for a house that finishes out at $100/square foot, as opposed to $170/square foot.”
The answer is not always solved by getting off-the-shelf manufactured components, like columns, he says. Often these have too much detail. “Then you raise the bar for the rest of the building to a level that the craft or budget can’t support. You have these fussy columns that are out of sync with the rest of the house. It’s better to do a simple house well than a more formal house poorly.”

Understanding production building
The production builder system is set up so that one subcontractor follows on another, Powers explains. “For the design to be easy to complete, it has to insist on relatively little interaction between the subcontractors,” he says. “Any time you set up details that demand careful coordination or change the standard sequence of the trades you create a problem.”
The results are bad details, poor proportions, and a general flatness of appearance that recurs time and time again in production-built TNDs. Money is often spent unnecessarily, while the problems remain — clustered around porch columns, windows, eaves and cornices, other trim, and building volume. Powers’s research has revealed simple, relatively inexpensive strategies in all of these areas to get a good-looking house that may not be the cheapest possible construction “but is less expensive than you would expect,” he says.

Porch Columns
It’s possible to walk through a TND and see every single porch column misaligned with the beam. While individual homebuyers may not notice this particular mistake, it detracts from the authenticity of the neighborhood and ultimately the pedestrian experience. The misalignment is caused by lack of communication between the framers and the trim workers. One way to avoid the problem is with a square column, Powers says (see images below).

The square column is the most foolproof way to get production builders to correctly line up posts and beams on a porch (at left). Chamfers (middle) simulate the narrowing of the column toward the top. With square columns, the support post is lined up at the corner. That is not the case with round columns (see comparison at right), which are a little more difficult for subcontractors, Powers notes.

Windows
The important principles here involve proportion and shadow, Powers says. “The unifying nature of modern construction is the flatness. What we are always trying to do is increase the apparent depth of things.” A builder can buy windows with built-in depth and shadow lines, but these are quite expensive. Many production builders use vinyl windows that have no depth to their appearance. They are often installed with no trim, as well.
Powers’s solution is to use vinyl replacement windows set within a site-built and flashed window frame. This allows them to be placed farther back in the depth of the wall creating a stronger shadow. (see images below). The flashing and frame add cost, Powers says, but are still less expensive than buying upgraded windows.
Another great way to add dignity to the house with minimal extra cost is to purchase taller windows and place them close to the floor (on the first floor, especially), he says. “We get the tallest windows we can order off the shelf — usually 6 feet or 6.5 feet tall, and set the heads at 8 feet above the floor, if we have room,” he explains. “That results in great proportion that people always notice.” These taller windows add about $100/window.

Vinyl windows save a lot of money but have a flat profile. The illustrations at left show how to use a replacement window to set the window back from the facade to give it a third dimension, shadow lines, and substantially improve appearance.

Eave returns
Where eaves turn the corner of the gable is a detail that is routinely mangled in new houses. The most common “solution” is the notorious pork chop return (see images, below left). Even when builders try to create an actual return,

Eave return errors: roof pitch too steep and no symmetry with corner board (at left), and the clunky pork chop return (at right.)

it is often done wrong in two ways — the roof pitch is too steep and it is not symmetrical with the corner board of the house (see photo at top left). A correct eave return should not add any additional cost to the house, Powers says. There are two rules to follow: 1) The small area of roof over the return should not be visible from the ground, which means the pitch should be 1:12, the minimal level that can shed water. 2) The return should be symmetrical in every way with the corner board. The simplest way to handle this detail is the boxed eave (see image series, below).

The two series of images (above and at right) shows two simple, fast, inexpensive ways for production builders to create an attractive eave return. The upper series creates a wider overhang and does not require a small roof over the return. Note that the return is symmetrical with the corner board in both cases.

Raising the eaves
The truss supporting the roof is typically placed right on top of the second floor plate, which puts the eaves just above the second-floor windows. This gives the sense that the roof is pulled down too low, giving the house bad proportions, Powers says. The solution is to order a truss with a much taller heel or plate that raises it up. “It doesn’t add work, it just changes the dimension of what the builder is going to order,” Powers says. “This has a huge effect. The eaves line up another foot above the top of the windows, which gives you room to build a proper level of trim all around. It’s the difference between a proud hat and a dunce cap that is pulled down around your ears.”

The raking cornice following the roofline has a different profile than the eave cornice — the connection between the two, below, is often poorly handled by production builders. The least expensive yet good-looking solution is to run the eave cornice directly across, as shown at right.

Reducing trim steps
Powers concentrates on reducing the number of steps required for builders to complete each piece of trim in a way that creates the reasonable approximation of the classical detail. One problem area is where the raking cornice and eave cornice collide. Because the raking cornice (below the roof on the gable end) has a different profile from the eave cornice, it is difficult to resolve this point. Powers recommends simply running the eave cornice across (see image at left). That’s not classically correct, but it looks good and it requires the builder to make one cut.

Volume
“If you look at traditional houses, they are always driven by an absolute efficiency of form,” Power says. “This also results in satisfying proportions compared to what you see today.” Everything in the house should be laid out, if possible, on a two-foot grid, which allows 4-by-8-foot sheets of plywood to be used efficiently (see image at top of page). “Planning the entire house based on this module minimizes the number of cuts and waste,” he says.
“The architect’s job should be to make it easier — not harder — for the builder,” he concludes. “We see our job as brokering the deal between the standard production detail and ideal historical detail. Both sides get what they want and everybody wins.”