OBSERVATIONS
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IN THIS ISSUE
TO REPLACE OR NOT TO REPLACE... The home-improvement industry, abetted by energy-conservation codes that were not written with old buildings in mind, encourages homeowners to replace their "old, outmoded" windows with new, "energy-saving" units. I recently got a call from a homeowner who was struggling with this issue, and wanted some advice. The first thing I said was that for a new building, energy-saving windows would be the way to go, even if the code didn't require them. But when it comes to replacing hundred or two-hundred year-old windows, the issue is not so simple. To begin with, existing windows are part of the building's historical fabric--integral parts of the structure and its history. They are important character-defining elements. How windows look matters. Discarding them erodes the building's historical character, esthetics, and integrity. Single-glazed, divided-light windows look different from double-glazed muntin-gridded sash. Even if you dislike the appearance, and the very idea, of "imitation divided light" sash, historically appropriate-looking energy-efficient divided-light sash cannot be successfully manufactured. Double glazing is several times as thick as and more than twice heavy as single, and requires stronger (bigger) muntins to carry its weight. Wider muntins are also required to hide the seal that runs around the edges of each piece of double glazing. A double-glazed divided-light sash is thick and clumsy-appearing, and looks nothing like an historic window. The closest one can come to an historic appearance is to use applied grillework--which can be appropriately scaled to the muntins used in single-glazed sash--on large lights of insulating glass. Cost is a factor, too: High-quality energy-efficient windows are expensive: $300 to $500 per window plus removal of the old and installation of the new, for a total of $500 to $700 per window. To get the annual energy saving necessary to pay back the raw cost in ten years, therefore (never mind interest on the loan that paid for them), each window must produce an annual energy cost saving of $50 to $70. That just isn't possible. But surely, replacing your old windows with energy-efficient untis will solve your window problem once and for all, won't it? Well, actually, no, it won't.
In contrast, old windows are made by setting individual lights of glass in a grid of suporting muntins. When a pane breaks, the window is easily repaired by removing the glass and replacing it with a new piece. The sash itself can be repaired, even when it has been neglected: So long as it does not yield to pressure at any joint where two muntins cross, it is almost certainly structurally sound, and therefore can be appropriately repaired.
But old windows will never achieve the thermal performance of energy-efficient units, will they? No, they are not likely to do that, although significant upgrades are possible at reasonable cost with weatherstripping and storm sash, inside and out. But suppose it were possible--could you then reasonably expect to upgrade the thermal performance of the whole house to the point where such windows were necessary and appropriate? Windows are an important piece of a building's thermal envelope, but they are only a piece. To focus on windows to the exclusion of an old building's other thermal issues such as shallow wall cavities in which to place insulation (or no wall cavities at all, in the case of plank-framed houses), porous exterior walls through which drafts enter, and an inadequately controlled and antiquated heating system that does a poor job of delivering heat where and when it is needed, is to lose sight of the forest for the trees. For a research-based take on the economics of replacing old windows, see Creating windows of Energy-Saving Opportunity, by Andrew Shapiro and Brad James, in the September/October 1997 issue of Home Energy magazine. Back to the top WHERE HAVE ALL THE GOOD ADDITIONS GONE? You're getting ready to add to your house, and you want to look at some good house extensions to get some ideas. So you get in your car and head off into likely territory, and see... what?
The odds are high that unless you are a very sophisticated observer, all you will see is a depressing lot of mediocre additions (or worse). So you return home puzzled and discouraged. There must be some good house extensions out there somewhere; why can't you find them? Often, the answer lies in the nature of a good house extension. The best ones call no attention to themselves, and are not easy to spot. They appear to grow naturally out of the parent structure, as though they had been intended ever since the house was initially built. Massing, texture, roof slopes, window sizes, and a host of other attributes are closely related to the structure to which they have been added, making them inconspicuous. No wonder they're hard to notice! That does not mean that extensions must be indistinguishable from the original building to be successful. Subtle differences are a useful way of distinguishing between what was there before and what was added (and when dealing with a museum restoration, those differences become an essential way to distinguish between what is old and what is restoration). It does mean that a faddish addition that calls attention to itself is not likely to be as successful as a one that seeks to extend and reinforce the building as a whole. So, good house extensions are out there. You just have to look carefully to see them... and that's one reason why they're good.
Back to the top Lately I've been doing an increasing number of summary building assessments, involving from four hours or less to a day and a half on site, usually followed by written reports. Some have been CAP assessments,* about which long-time readers have heard before. Others have been similar, but not funded by Heritage Preservation. Some have been strictly architectural-historical, while others have addressed overall building conservation and maintenance issues. In addition to museum organizaions, I have conducted a gratifying number for churches and for private homeowners. These brief studies shed light on buildings' histories and evolutions, identify important issues needing attention, and provide outlines of the work needed to address them. They are exceedingly flexible and able to respond to building-owners' specific needs. If you have building that you want, or need, to know better, a summary assessment may help you get that knowledge, at a reasonable fee. *) The Conservation Assessment Program, supported by grants, allows small museums to obtain professional assessments of their buildings and collections. Funded by the Institute for Museum and Library Services, it is administered by Heritage Preservation, in Washington DC. It is described in more detail in Observations 11. An assessment report (edited to preserve confidentiality) can be found at Observations 21. Back to the top BARN CONVERSIONS--A CURMUDGEON'S VIEW... An appealing old-building fantasy is to convert a barn, with its soaring interior spaces and wonderful patina of aged wood, into a residence. Indeed, over the years, many barns have been successfully converted. Making a building that was originally intended to house livestock, fodder, farm equipment, and "by-products" into an up-to-date house, though, can be more tricky than it looks. There are obvious design issues, such as sensitively adding windows and exterior doors, and providing bed-rooms, baths, and other private spaces on the interior without losing the sense of space that makes the barn so attractive in the first place. Beyond that, though, there are problems intrinsic to the physical fabric of barns: First is the nasty little matter of foundations: Old barns, like most agricultural buildings, tend not to have very formal foundations. Unless the main floor is raised above grade or the barn has been built into the side of a slope, old barn foundations tend to consist of a few big stones placed beneath the structural posts, about a foot and a half to two feet below grade--well above the frost line in New England. Consequently, as the ground moves during the seasonal freeze-and-thaw cycle, the foundations (and the barn that rests on them) also rise and fall. This movement may not be significant in a building that has minimal interior finish, but it will wreak havoc on plaster walls, plumbing and heating lines, door swings, and other accouterments of finished space. Installing more formal and deeper foundations is straightforward, but it is much more expensive to build a foundation under an existing building than to construct one first and then erect the building atop it. Some years ago we put a basement beneath a summer house that had originally been built on posts... for a cost of about ten times what it would have been had the house not been in the way. And then there is the matter of interior finish: One of the most appealing aspects of barns is their evocative, cathedral-like interiors, rich with the brown color of old wood. Those beautiful exterior walls, though, tend to let in a lot of wind, and as for insulation, an inch or two of board (and shingles or clapboards) doesn't do much to keep heat in. Even leaving aside today's stiff energy codes, something has to be done to tighten up the exterior envelope and make it more thermally efficient. Where can that insulation and draft-barriering be put? If it is installed on the interior, those wonderful wooden surfaces will disappear behind new insulation and finish. Of course, one can always fake an old interior finish, and even (perish the thought!) remove the exterior sheathing, replace it with plywood, and re-install it inside the insulation. Alternatively, one might insulate over the outside of the building and add new exterior roof and wall finish. That makes it likely that early exterior finish and trim will be lost, or at best will have to be pieced out with new work, since the exterior of the building will now be larger in all directions than before. This is not to say that you shouldn't consider converting a barn to a residence. Just be aware that if you do, it won't be easy. Back to the top
Copyright 1991-2008 Allen C. Hill |
