Look beyond the never-to-be-settled debate over siding’s merits/sins. It’s an affordable, energy-conscious update. It can even look good.
By Mark Feirer of This Old House magazine
The Benefits of Vinyl Siding
There are few subjects in the whole arena of residential construction products that draw battle lines as sharply as vinyl siding.
Proponents harp on the fact that it never needs painting, while its detractors insist that houses should never be covered with anything but real wood.
As a building material, vinyl siding is relatively new — it was introduced in the late 1950s as a substitute for aluminum siding. But its reputation was tarnished in the early days when it cracked, faded, buckled, and sagged.
Ongoing changes in the product’s chemistry and installation techniques have improved its performance and furthered its acceptance by builders and homeowners.
In fact, vinyl has captured 32 percent of the U.S. siding market for new homes, with no end in sight to its growing popularity. The reason, in part, is because it’s often (but not always) cheaper than red cedar or redwood and takes less time to install.
A mid-grade vinyl costs about $1.60 per square foot to install, not including the necessary trim pieces, while the installed price of mid-grade cedar clapboard, exclusive of trim and paint, is about 2.5 times higher. (Some premium vinyls cost about the same as the best grade of cedar, but the installed cost is still lower because it goes up faster and doesn’t need painting.)
For many people, price isn’t the issue at all; the real seduction of plastic siding is reduced maintenance. That’s exactly why a wood guy like This Old House general contractor Tom Silva put vinyl on his house 20 years ago.
“I don’t have time for painting,” he explains. “I’d rather spend weekends on my boat.” Of course, with the right maintenance, wood will last indefinitely. Vinyl can’t match that claim because no one knows for sure how long it will last.
Installer Joe Fagone slides a cut-to-fit, 4-foot-long panel of embossed-shingle siding around a window.
All Plastic Siding is Not the Same
Vinyl is a polymer formed during a chemical do-si-do between ethylene gas and chlorine, which produces a fine white powder called vinyl resin. When it’s melted and mixed with different additives, the resulting compound can be as rigid as pipe, as supple as a shower curtain, or durable enough to survive the heavy foot traffic on a kitchen floor.
New, so-called virgin vinyl siding has a greater complement of the key additives that impart flexibility and resistance to UV degradation. Some manufacturers will tout their product as 100 percent virgin (along with a mention of its supposed superiority), but most siding is made with a core of remelted vinyl top-coated with virgin material.
Typically, vinyl siding is extruded through a die, but to produce the deepest patterns and crispest edges, panels must be molded from polypropylene, a more expensive plastic. Molded panels are typically no more than 4 feet long, while vinyl extrusions can be virtually any length.
Rap on a vinyl-sided wall with your knuckles, and it will flex and sound hollow. That’s because, in most cases, only a relatively small area of a vinyl panel is actually resting against the sheathing.
A thin panel, or one without support, is more likely to sag over time. The thinnest siding that meets code is .035 inch thick. Premium siding can be .044 to .048 inch, and a few manufacturers sell .055-inch siding. The thicker sidings tend to be stiffer, and therefore more resistant to sagging, but stiffness depends on other characteristics as well.
Panels with a folded-over, doubled nailing hem and a relatively deep profile tend to be stiffer than others, as do those with narrow “clapboards”: The more bends the better. Although claims are made that thicker siding is also more impact resistant than thin siding, test results suggest that it has more to do with its chemical makeup, which, unfortunately, is not available to consumers who want to compare products.
Thinner, less-stiff sidings can also be sucked off a house when high winds blow. Reading the manufacturer’s warranty should give you a good indication of the product’s ability to handle heavy weather. Some even comply with the 146-miles-per-hour wind code in hurricane-prone Miami, Florida.
One siding, Wolverine Millennium, comes with a “won’t-blow-off” warranty, and its literature states that it will withstand 180-mph winds, when nailed properly.
A panel of polypropylene siding slips into a grooved “corner board” of the same material. Panels expand and contract with temperature changes and shouldn’t be installed tight to trim pieces.
While wood siding is fastened tightly to the house, vinyl siding literally hangs from nails driven through horizontal slots at the top of a panel’s nailing hem. The reason for the loose nailing has to do with the vinyl’s (and polypropylene’s) need to expand or contract as the temperature changes: A 12-foot length of plastic siding can expand as much as 5/8 inch with seasonal temperature swings. If nailed tight to a wall, it can buckle on hot days.
“The worst thing you can do is nail vinyl tight,” says Tom Silva. To ensure that the panel is free to move, the nailheads shouldn’t contact the hem, but should be left about 1/32 inch proud. Conversely, if nailed too loosely the panels will rattle noisily whenever the wind blows.
Vinyl’s tendency to move means that panels can’t be butted tight to trim, either. Quality-conscious installers leave about 1/4 inch of clearance (3/8 inch in temperatures below 40°F) at the end of panel courses; at corners and door and window openings a trim piece called J-channel covers and conceals the resulting gap. Other proprietary trim pieces, made by manufacturers to fit their own brand of siding, include soffits, rake boards, and crown moldings. All help to improve the appearance of an installation, giving it a more custom look.
In addition to J-channels, one characteristic that distinguishes vinyl from other siding is its overlaps. While lengths of wood (or cement) siding meet in an unobtrusive butt, vinyl panels must be overlapped by about 1 inch wherever they meet, resulting in telltale vertical lines. The thicker the vinyl, the more obvious the overlap. Compounding the problem, most vinyl siding panels are molded to represent double or even triple widths of clapboards. This slashes installation time dramatically, but it also makes panel overlaps even more visible. A good installer will orient overlaps away from dominant views, for example, by running the siding from a back corner to a front corner. On the front of the house, panels should be installed so seams are least visible to someone approaching the front door.
Contrary to what many people expect, vinyl is actually less likely than wood to trap moisture, Tom says. “There are tiny weep holes in the butts of the panels. And because it’s hung loosely, air can move behind it.” Just make sure your siding contractor first installs flashing and either housewrap or builder’s felt, just as he would under wood siding.
Every quality vinyl siding job starts with the contractor. Dont hesitate to ask potential installers for their certifications — most of the large manufacturers certify installers in proper installation techniques — and for the names of satisfied customers. Also check complaint lists established with local and state business associations, as well as with state contractor licensing boards.
Siding is nailed loosely through horizontal slots in the hem at the top of each panel. Tightly nailed plastic siding can buckle on very hot days. The L-shaped clip under the nailing slot hooks into a channel in the butt of the panel above.
Not Entirely Maintenance Free
To keep vinyl siding looking its best, it should be washed periodically to remove the mold, mildew, dirt, and chalky oxidation that collects on the surface. Tom uses a soft-bristle brush and a bucket with a 30/70 mix of vinegar and water. (If that doesn’t do the job, the Vinyl Siding Institute suggests mixing 1/3 cup laundry detergent, 2/3 cup powdered household cleaner, 1 quart liquid laundry bleach, and 1 gallon water.) He just brushes it on, working from the bottom up, and gently hoses it off. Tom discourages homeowners from using a power washer on their siding; the high-pressure equipment is likely to drive water behind the panels.
Repairing a damaged panel is simple. With a zip tool and a flick of the wrist, Tom simply unhooks it from the ones above and below, then pulls out the nails. A new panel can then be snapped in place, nailed, and re-hooked. The biggest problem is matching the replacement to the surrounding pieces, which will undoubtedly have faded. “What I’ll do,” Tom says, “is replace the damaged piece with some siding from a less conspicuous part of the house.” Then he replaces that piece with the new, unfaded length.
All vinyl siding will fade somewhat. After 10 to 15 years, the change can be significant. When that happens, or if you simply want to change its color, vinyl can be painted, as self-defeating as it may seem. (Check with the manufacturer first; many companies void the warranty if siding is painted.) Wash the siding first, and use latex paint, which will flex with the vinyl’s movement. But don’t count on changing a pale-yellow house to hunter green; dark colors absorb more heat than lighter ones and can cause panels to expand too much and buckle. (For that very reason, vinyl’s color palette is limited to lighter shades.)
Tom is well aware of the fact that plastic siding draws strong opinions from his clients. “It’s pretty hard to convince someone who wants vinyl to use wood siding instead, and vice versa,” he says. “Some people like it and some don’t, just as some people like Fords and some prefer Chevys.” Whether vinyl siding is good or not depends a lot on the quality of the product and the installation job. “Would I put it on my house again, if maintenance issues weren’t a factor? Probably not,” Tom says. “I really prefer wood.” But he really, really doesn’t like to paint.
Plastic siding is quick to install. The seven-man crew from Hansen Home Designs trimmed and sided this 3,200 square-foot house in less than two days. Photo taken April 4, 2002.
Re-siding with Vinyl
Much of what appeals to us about older historic houses, apart from their architectural style, is the graceful moldings, well-proportioned trim, subtle shadow lines, even the slight irregularities in the spacing of the siding — testaments to the skills of this country’s housewrights. But in countless slipshod re-siding jobs, where vinyl is slapped up over the existing shingles or clapboards, these details have been obliterated, making the facades of handsome gingerbread houses as plain as sheet cakes. “I’ve seen a lot of cases where they’ve sawed off moldings, window trim, cornices, even knocked them off with hammers,” says Tom. “It looks worse than terrible. And it takes away what makes old houses special.”
For those contemplating having a house re-sided, Tom recommends finding a contractor who specializes in old-house work, not just in vinyl siding, and insisting that all the architectural details remain in place. “Run J-channel around them and butt the siding into it,” he says. “Of course, it takes more time and money to do it this way.” A proper paint job may make more sense, if that’s the case. Sometimes, re-siding jobs are sold as a way to “tighten up” the house and reduce energy bills. The installers simply nail up a layer of foil-faced foam before the vinyl goes up. Tom doesn’t think much of this practice. “The foam panels are only 3/8 inch thick; they don’t add much R-value,” he says. “You’d be better off packing the walls with blow-in cellulose.” The final word: If you have any doubts about its effects, don’t put vinyl siding on your old house.