Go for longevity
Your home's exterior siding does more than give your home an attractive, finished look. It's your first line of defense against the elements. Wood and vinyl are most commonly used, but you can probably find homes in your neighborhood sporting a host of other materials as well.
So how do you decide which kind of siding is best for you? The most important things to think about are: How many years will it last? How much maintenance will it require? Where did the raw materials come from and were they responsibly harvested or mined? Is the manufacturing process energy intensive or polluting? When the siding reaches the end of its life, can it be reused or recycled?
In short, choosing siding is a balancing act. You probably can't make a perfectly green choice. But if you give it some thought, you can be perfectly happy.
- Stand by your siding. Replacing siding for esthetic reasons may not be a good idea because of all the waste you'll be creating. Look for ways to spiff it up rather than replace it: a power washing or a new paint color may give your old siding new life. On the other hand, if your siding is rotting, warping, or letting in rain, repairing or replacing it is essential to protect your home's structure from deterioration.
When shopping, look for
- Durability. As with roofing, the greenest siding products are those that last the longest. (The exception to this rule is vinyl, a durable product that produces hazardous pollution during manufacturing and disposal). Choosing siding that is durable and suitable for your climate will help extend the life of your home, reduce your maintenance and repair costs, and keep old siding from filling up landfill.
- Vinyl siding creates highly toxic byproducts during manufacturing and incineration.
- Engineered wood siding (OSB, hardboard, and plywood) is less durable than solid wood.
- Here's how various sidings compare in terms of material and installation costs: 1) Low: vinyl, aluminum, and engineered wood 2) Medium: fiber-cement 3) Medium to high: solid wood 4) High: stucco and masonry. But those are just the front-end costs. Don't forget to factor in the product's toughness and its length of life. Engineered wood, for instance, looks like a bargain until you consider its high costs for maintenance, repair, and replacement.
- There are environmental and practical pros and cons to all of the above. Wood siding is fine if it is salvaged or FSC-certified, but it requires frequent painting or staining to keep it from rotting or warping. Stucco, fiber-cement, aluminum, and masonry siding are long lasting--and aluminum has the added benefit of being recyclable. But each of these materials takes at least a modest toll on the environment.
- Here's more detail about your siding options:
- Aluminum. Aluminum siding first appeared on homes in 1940s but lost favor when cheaper vinyl siding came on the market in the ‘50s. Aluminum siding holds up well to weather but can dent. It requires a lot of energy to produce but usually has high recycled content, and it's recyclable at the end of its life.
- Engineered wood. Hardboard, plywood, and oriented strand board (OSB) are made from wood chips (or in the case of plywood, wood veneers) bound with phenol formaldehyde. They're cheaper than solid-wood siding, but in general less durable because if the fibers get wet, they'll swell, which can lead to premature disintegration. Proper installation and regular repainting are a must. One environmental advantage to OSB and hardboard is that they use small, lower-grade trees than solid wood siding or plywood. At least one company makes a composite wood siding product using FSC-certified wood and recycled wood chips.
- Fiber-cement siding is a blend of portland cement, wood fibers, sand, and clay. It comes in boards and panels, often with texturing that makes it hard to distinguish from solid wood siding. A similar product sold in decades past contained asbestos; fiber-cement siding does not. It's fire and rot resistant, requires repainting or restaining less frequently than wood, and is about half the price of solid wood siding. On the minus side: portland cement is an energy-intensive material to manufacture, and while some fiber-cement products are made in the United States, they typically use imported wood fibers that aren't FSC certified. Sawing fiber-cement siding creates a lot of silica dust, which you don't want in your lungs. To cut down on the dust, use special shears designed to cut fiber-cement siding.
- Masonry. These days, most masonry siding is actually a veneer installed over the home's wood framing--not solid walls of brick or stone. Brick, natural stone, and manufactured stone (a cement-based product poured into molds and finished to look like real stone) are relatively environmentally benign. Durable and fire resistant, they require virtually no maintenance. They're made from abundant although nonrenewable resources. Firing brick does require considerable energy, as does portland cement. To lessen the impacts, look for salvaged or locally quarried stone or locally made brick.
- Stucco. Most stucco today is not the old-fashioned cement-based plaster. Also known as EIFS (Exterior Insulation and Finish System), synthetic stucco is applied over foam insulation boards on the outside of the house. The energy savings from this added insulation are one of the biggest benefits of synthetic stucco. An acrylic-based compound, synthetic stucco is somewhat flexible even after it dries so it's less likely to crack than traditional stucco. It can be prepared with colors mixed in so it never needs repainting. Proper installation is a must to make sure that any moisture that gets behind the stucco can drain away from the wall. (The synthetic stucco industry came under fire starting in the 1980s because of moisture damage related to installation problems.) EIFS is an expensive siding choice but not as pricey as traditional stucco. It may be hard to find laborers skilled in applying traditional stucco in your area. Both types of stucco provide good fire resistance.
- Vinyl siding first started appearing on homes in the 1950s and now seems ubiquitous. On the plus side, vinyl siding is inexpensive, durable (some products have 50-year warranties), requires no maintenance other than an occasional hosing off, comes in lots of colors and textures, and can sometimes be installed right over existing siding. So what's not to like? First off, it's energy intensive to manufacture, and in the process creates dioxin, a potent carcinogen. It also can produce dioxin at the end of its life, when it is incinerated or burns in a house fire.
- Wood. Solid wood siding comes in boards, panels, or shingles. Cedar, redwood, and cypress have long been prized for this purpose because of their innate resistance to moisture and insects. On the plus side, wood siding is made from a renewable resource, uses less energy to manufacture than more highly processed materials, and results in virtually no wood waste because various industries make use of all the scrap wood. What's more, old siding taken off of a house can sometimes be reused. The biggest drawbacks of wood siding are its high maintenance requirements (painting or staining every five to ten years) and the environmental impacts of harvesting the trees. Unfortunately, some siding products are still being manufactured from trees harvested from old-growth forests. That's because the old giants have the most durable, weather-resistant heartwood. To protect these precious forests, your best bet is to choose Forest Stewardship Council (FSC)-certified siding. It's not easy to find, but is offered by a growing number of suppliers. Another option that's green (although neither cheap nor easy to find) is reclaimed wood siding, which is typically milled from lumber salvaged from old buildings and other structures.
...to your health
Durable, properly installed siding keeps rainwater out of your walls, making it less likely that unhealthy mold will grow inside walls.
...to the Earth
Durable siding reduces demand for harvesting and extracting raw materials and reduces waste.
- Tempting fate. Wood siding is a poor choice for fire-prone areas.
- Ignoring details. If the layers underneath the siding, including sheathing and the "drainage plane" (often made of building paper), have not been properly installed, mold and rot can plague your house. Proper flashing around windows, doors, pipes, and all other wall penetrations is essential for the same reason. Some homes also have "rain screens," an air space between the siding and the building paper that provides additional drainage.
- Ignoring lead. Lead was a common additive in paints until the late 1970s, so millions of homes have wood siding painted with lead-based paint. A toxic metal, lead can be released when you power wash, sand, or cut into wood siding and trim.
- If you're tearing siding off your house, look for ways to keep it out of landfills. Sometimes wood siding that has been carefully removed can be reused, either on your home or someone else's. Fiber-cement siding, aluminum, stone, and brick may also be reusable.
- If you're using a contractor, here are some additional tips:
- If you need to repair or replace old siding, hire a contractor who specializes in the particular type of new siding you have chosen. If you are putting on new siding as part of a larger home improvement project such as building an addition, you'll likely have your general contractor handle the installation.
- When you have narrowed down your list of preferred siding contractors, get customer references for homes re-sided with the same material that will be used on your home. Make sure the references include some projects that are several years old, and visit the homes to see how well the material and workmanship held up.
- Sometimes new siding can be installed over old siding if it is in good condition, with no rotting, moisture damage, or warping. If the old siding needs to be removed, can it be salvaged or recycled? Make sure the contractors' estimates include removing and disposing of old siding. The estimates should also include doing any needed repair work to fix problems under the siding (like rot), to install a weather-resistant barrier like building paper under the siding, and to install flashing around doors, windows, and other openings in the walls.
- For general advice on what questions to ask contractors and other tradespeople, see our "What to Ask Your Contractor" article.